Diagnosis by integrating model-based reasoning with knowledge-based reasoning

NASA Technical Reports Server (NTRS)

Bylander, Tom

1988-01-01

Our research investigates how observations can be categorized by integrating a qualitative physical model with experiential knowledge. Our domain is diagnosis of pathologic gait in humans, in which the observations are the gait motions, muscle activity during gait, and physical exam data, and the diagnostic hypotheses are the potential muscle weaknesses, muscle mistimings, and joint restrictions. Patients with underlying neurological disorders typically have several malfunctions. Among the problems that need to be faced are: the ambiguity of the observations, the ambiguity of the qualitative physical model, correspondence of the observations and hypotheses to the qualitative physical model, the inherent uncertainty of experiential knowledge, and the combinatorics involved in forming composite hypotheses. Our system divides the work so that the knowledge-based reasoning suggests which hypotheses appear more likely than others, the qualitative physical model is used to determine which hypotheses explain which observations, and another process combines these functionalities to construct a composite hypothesis based on explanatory power and plausibility. We speculate that the reasoning architecture of our system is generally applicable to complex domains in which a less-than-perfect physical model and less-than-perfect experiential knowledge need to be combined to perform diagnosis.

Qualitative methods in quantum theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Migdal, A.B.

The author feels that the solution of most problems in theoretical physics begins with the application of qualitative methods - dimensional estimates and estimates made from simple models, the investigation of limiting cases, the use of the analytic properties of physical quantities, etc. This book proceeds in this spirit, rather than in a formal, mathematical way with no traces of the sweat involved in the original work left to show. The chapters are entitled Dimensional and model approximations, Various types of perturbation theory, The quasi-classical approximation, Analytic properties of physical quantities, Methods in the many-body problem, and Qualitative methods inmore » quantum field theory. Each chapter begins with a detailed introduction, in which the physical meaning of the results obtained in that chapter is explained in a simple way. 61 figures. (RWR)« less

Examining the Relationship between Role Models and Leadership Growth during the Transition to Adulthood

ERIC Educational Resources Information Center

Bowers, Jill R.; Rosch, David M.; Collier, Daniel A.

2016-01-01

Leadership and developmental scholars have highlighted the need to enhance youth leadership skills. Yet, research that explains youths' perceptions of how and when role models influences their leadership growth processes is limited. To address these gaps and begin to develop an understanding of youths' perspectives, we employed a qualitative,…

Qualitative research and the epidemiological imagination: a vital relationship.

PubMed

Popay, J

2003-01-01

This paper takes as its starting point the assumption that the 'Epidemiological Imagination' has a central role to play in the future development of policies and practice to improve population health and reduce health inequalities within and between states but suggests that by neglecting the contribution that qualitative research can make epidemiology is failing to deliver this potential. The paper briefly considers what qualitative research is, touching on epistemological questions--what type of "knowledge" is generated--and questions of methods--what approaches to data collection, analysis and interpretation are involved). Following this the paper presents two different models of the relationship between qualitative and quantitative research. The enhancement model (which assumes that qualitative research findings add something extra to the findings of quantitative research) suggests three related "roles" for qualitative research: generating hypothesis to be tested by quantitative research, helping to construct more sophisticated measures of social phenomena and explaining unexpected research from quantitative research. In contrast, the Epistemological Model suggests that qualitative research is equal but different from quantitative research making a unique contribution through: researching parts other research approaches can't reach, increasing understanding by adding conceptual and theoretical depth to knowledge, shifting the balance of power between researchers and researched and challenging traditional epidemiological ways of "knowing" the social world. The paper illustrates these different types of contributions with examples of qualitative research and finally discusses ways in which the "trustworthiness" of qualitative research can be assessed.

Modeling the X-Ray Timing Properties of Cygnus X-1 Caused by Waves Propagating in a Transition Disk

NASA Astrophysics Data System (ADS)

Misra, R.

2000-02-01

We show that waves propagating in a transition disk can explain the short-term temporal behavior of Cygnus X-1. In the transition-disk model, the spectrum is produced by saturated Comptonization within the inner region of the accretion disk where the temperature varies rapidly with radius. Recently, the spectrum from such a disk has been shown to fit the average broadband spectrum of this source better than that predicted by the soft-photon Comptonization model. Here we consider a simple model in which waves are propagating cylindrically symmetrically in the transition disk with a uniform propagation speed (cp). We show that this model can qualitatively explain (1) the variation of the power spectral density with energy, (2) the hard lags as a function of frequency, and (3) the hard lags as a function of energy for various frequencies. Thus, the transition-disk model can explain the average spectrum and the short-term temporal behavior of Cyg X-1.

Theoretical calculations of oxygen relaxation in YBa2Cu3O6+x ceramics

NASA Astrophysics Data System (ADS)

Mi, Y.; Schaller, R.; Sathish, S.; Benoit, W.

1991-12-01

A two-dimensional theoretical model of stress-induced point-defect relaxation in a layered structure is presented, with a detailed discussion of the special case of YBa2Cu3O6+x. The experimental results of oxygen relaxation in YBa2Cu3O6+x can be explained qualitatively by this model.

The Ether Wind and the Global Positioning System.

ERIC Educational Resources Information Center

Muller, Rainer

2000-01-01

Explains how students can perform a refutation of the ether theory using information from the Global Positioning System (GPS). Discusses the functioning of the GPS, qualitatively describes how position determination would be affected by an ether wind, and illustrates the pertinent ideas with a simple quantitative model. (WRM)

Junior high school students' cognitive process in solving the developed algebraic problems based on information processing taxonomy model

NASA Astrophysics Data System (ADS)

Purwoko, Saad, Noor Shah; Tajudin, Nor'ain Mohd

2017-05-01

This study aims to: i) develop problem solving questions of Linear Equations System of Two Variables (LESTV) based on levels of IPT Model, ii) explain the level of students' skill of information processing in solving LESTV problems; iii) explain students' skill in information processing in solving LESTV problems; and iv) explain students' cognitive process in solving LESTV problems. This study involves three phases: i) development of LESTV problem questions based on Tessmer Model; ii) quantitative survey method on analyzing students' skill level of information processing; and iii) qualitative case study method on analyzing students' cognitive process. The population of the study was 545 eighth grade students represented by a sample of 170 students of five Junior High Schools in Hilir Barat Zone, Palembang (Indonesia) that were chosen using cluster sampling. Fifteen students among them were drawn as a sample for the interview session with saturated information obtained. The data were collected using the LESTV problem solving test and the interview protocol. The quantitative data were analyzed using descriptive statistics, while the qualitative data were analyzed using the content analysis. The finding of this study indicated that students' cognitive process was just at the step of indentifying external source and doing algorithm in short-term memory fluently. Only 15.29% students could retrieve type A information and 5.88% students could retrieve type B information from long-term memory. The implication was the development problems of LESTV had validated IPT Model in modelling students' assessment by different level of hierarchy.

Qualitative Differences between Naive and Scientific Theories of Evolution

ERIC Educational Resources Information Center

Shtulman, Andrew

2006-01-01

Philosophers of biology have long argued that Darwin's theory of evolution was qualitatively different from all earlier theories of evolution. Whereas Darwin's predecessors and contemporaries explained adaptation as the transformation of a species' ''essence,'' Darwin explained adaptation as the selective propagation of randomly occurring…

Qualitative versus quantitative methods in psychiatric research.

PubMed

Razafsha, Mahdi; Behforuzi, Hura; Azari, Hassan; Zhang, Zhiqun; Wang, Kevin K; Kobeissy, Firas H; Gold, Mark S

2012-01-01

Qualitative studies are gaining their credibility after a period of being misinterpreted as "not being quantitative." Qualitative method is a broad umbrella term for research methodologies that describe and explain individuals' experiences, behaviors, interactions, and social contexts. In-depth interview, focus groups, and participant observation are among the qualitative methods of inquiry commonly used in psychiatry. Researchers measure the frequency of occurring events using quantitative methods; however, qualitative methods provide a broader understanding and a more thorough reasoning behind the event. Hence, it is considered to be of special importance in psychiatry. Besides hypothesis generation in earlier phases of the research, qualitative methods can be employed in questionnaire design, diagnostic criteria establishment, feasibility studies, as well as studies of attitude and beliefs. Animal models are another area that qualitative methods can be employed, especially when naturalistic observation of animal behavior is important. However, since qualitative results can be researcher's own view, they need to be statistically confirmed, quantitative methods. The tendency to combine both qualitative and quantitative methods as complementary methods has emerged over recent years. By applying both methods of research, scientists can take advantage of interpretative characteristics of qualitative methods as well as experimental dimensions of quantitative methods.

Thinking about internal states, a qualitative investigation into metacognitions in women with eating disorders

PubMed Central

2013-01-01

Background There is a need for qualitative research to help develop case conceptualisations to guide the development of Metacognitive Therapy interventions for Eating Disorders. Method A qualitative study informed by grounded theory methodology was conducted involving open-ended interviews with 27 women aged 18–55 years, who were seeking or receiving treatment for a diagnosed ED. Results The categories identified in this study appeared to be consistent with a metacognitive model including constructs of a Cognitive Attentional Syndrome and metacognitive beliefs. These categories appear to be transdiagnostic, and the interaction between the categories is proposed to explain the maintenance of EDs. Conclusions The transdiagnostic model proposed may be useful to guide the development of future metacognitive therapy interventions for EDs with the hope that this will lead to improved outcomes for individuals with EDs. PMID:24999403

Magnetospheric accretion models for T Tauri stars. 1: Balmer line profiles without rotation

NASA Technical Reports Server (NTRS)

Hartmann, Lee; Hewett, Robert; Calvet, Nuria

1994-01-01

We argue that the strong emission lines of T Tauri stars are generally produced in infalling envelopes. Simple models of infall constrained to a dipolar magnetic field geometry explain many peculiarities of observed line profiles that are difficult, if not impossible, to reproduce with wind models. Radiative transfer effects explain why certain lines can appear quite symmetric while other lines simultaneously exhibit inverse P Cygni profiles, without recourse to complicated velocity fields. The success of the infall models in accounting for qualitative features of observed line profiles supports the proposal that stellar magnetospheres disrupt disk accretion in T Tauri stars, that true boundary layers are not usually present in T Tauri stars, and that the observed 'blue veiling' emission arises from the base of the magnetospheric accretion column.

Theories of dynamical phenomena in sunspots

NASA Technical Reports Server (NTRS)

Thomas, J. H.

1981-01-01

Attempts that have been made to understand and explain observed dynamical phenomena in sunspots within the framework of magnetohydrodynamic theory are surveyed. The qualitative aspects of the theory and physical arguments are emphasized, with mathematical details generally avoided. The dynamical phenomena in sunspots are divided into two categories: aperiodic (quasi-steady) and oscillatory. For each phenomenon discussed, the salient observational features that any theory should explain are summarized. The two contending theoretical models that can account for the fine structure of the Evershed motion, namely the convective roll model and the siphon flow model, are described. With regard to oscillatory phenomena, attention is given to overstability and oscillatory convection, umbral oscillations and flashes. penumbral waves, five-minute oscillations in sunspots, and the wave cooling of sunspots.

Shock Sensitivity of energetic materials

NASA Technical Reports Server (NTRS)

Kim, K.

1980-01-01

Viscoplastic deformation is examined as the principal source of hot energy. Some shock sensitivity data on a proposed model is explained. A hollow sphere model is used to approximate complex porous matrix of energetic materials. Two pieces of shock sensitivity data are qualitatively compared with results of the proposed model. The first is the p2 tau law. The second is the desensitization of energetic materials by a ramp wave applied stress. An approach to improve the model based on experimental observations is outlined.

Systems analysis of the vestibulo-ocular system. [mathematical model of vestibularly driven head and eye movements

NASA Technical Reports Server (NTRS)

Schmid, R. M.

1973-01-01

The vestibulo-ocular system is examined from the standpoint of system theory. The evolution of a mathematical model of the vestibulo-ocular system in an attempt to match more and more experimental data is followed step by step. The final model explains many characteristics of the eye movement in vestibularly induced nystagmus. The analysis of the dynamic behavior of the model at the different stages of its development is illustrated in time domain, mainly in a qualitative way.

Students Explaining Science--Assessment of Science Communication Competence

ERIC Educational Resources Information Center

Kulgemeyer, Christoph; Schecker, Horst

2013-01-01

Science communication competence (SCC) is an important educational goal in the school science curricula of several countries. However, there is a lack of research about the structure and the assessment of SCC. This paper specifies the theoretical framework of SCC by a competence model. We developed a qualitative assessment method for SCC that is…

An Applied Introduction to Qualitative Research Methods in Academic Advising

ERIC Educational Resources Information Center

Hurt, Robert L.; McLaughlin, Eric J.

2012-01-01

Academic advising research aids faculty members and advisors in detecting, explaining, and addressing macro-level trends beyond their local campus. It also helps legitimize the professional nature of academic advising, moving it beyond mere prescriptive models that focus on rules and course selection. Due to the erroneous belief that skills in…

High harmonic generation at the tunneling ionization of atoms by intense laser radiation near the classical cut-off

NASA Astrophysics Data System (ADS)

Gets, A. V.; Krainov, V. P.

2018-01-01

The yield of spontaneous photons at the tunneling ionization of atoms by intense low-frequency laser radiation near the classical cut-off is estimated analytically by using the three-step model. The Bell-shaped dependence in the universal photon spectrum is explained qualitatively.

Modeling and Measuring the Structure of Professional Vision in Preservice Teachers

ERIC Educational Resources Information Center

Seidel, Tina; Stürmer, Kathleen

2014-01-01

Professional vision has been identified as an important element of teacher expertise that can be developed in teacher education. It describes the use of knowledge to notice and interpret significant features of classroom situations. Three aspects of professional vision have been described by qualitative research: describe, explain, and predict…

Engaging Students in Analyzing and Interpreting Data to Construct Mathematical Models: An Analysis of Students' Reasoning in a Method of Initial Rates Task

ERIC Educational Resources Information Center

Becker, Nicole M.; Rupp, Charlie A.; Brandriet, Alexandra

2017-01-01

Models related to the topic of chemical kinetics are critical for predicting and explaining chemical reactivity. Here we present a qualitative study of 15 general chemistry students' reasoning about a method of initial rates task. We asked students to discuss their understanding of the terms rate law and initial rate, and then analyze rate and…

Qualitative Research in Adult, Career, and Career-Technical Education. Practitioner File.

ERIC Educational Resources Information Center

Imel, Susan; Kerka, Sandra; Wonacott, Michael E.

Directed at practitioners in adult and career education, this document defines qualitative research, compares qualitative research to quantitative research, describes the "war" between proponents of each kind of research, describes how to assess qualitative research, and explains how to choose and use qualitative techniques. Pitfalls of…

Refinement of the magnetic composite model of type 304 stainless steel by considering misoriented ferromagnetic martensite particles

NASA Astrophysics Data System (ADS)

Kinoshita, Katsuyuki

2017-05-01

We improved a magnetic composite model that combines the Jiles-Atherton model and Eshelby's equivalent inclusion method to consider misoriented martensite particles. The magnetic permeability of type 304 stainless steel were analyzed by using both experimental data on the orientation distribution of type 304 stainless steel specimens and the improved model. We found that the model is able to qualitatively explain the variation of permeability with the orientation angle and orientation distribution, an effect that depends on the direction of the excitation magnetic field.

Investigating students’ mental models about the nature of light in different contexts

NASA Astrophysics Data System (ADS)

Özcan, Özgür

2015-11-01

In this study, we investigated pre-service physics teachers’ mental models of light in different contexts, such as blackbody radiation, the photoelectric effect and the Compton effect. The data collected through the paper-and-pencil questionnaire (PPQ) were analyzed both quantitatively and qualitatively. Sampling of this study consists of a total of 110 physics education students who were taking a modern physics course at two different state universities in Turkey. As a result, three mental models, which were called the beam ray model (BrM), hybrid model (HM) and particle model (PM), were being used by the students while explaining these phenomena. The most model fluctuation was seen in HM and BrM. In addition, some students were in a mixed-model state where they use multiple mental models in explaining a phenomenon and used these models inconsistently. On the other hand, most of the students who used the particle model can be said to be in a pure model state.

The Impact of Welfare State Regimes on Barriers to Participation in Adult Education: A Bounded Agency Model

ERIC Educational Resources Information Center

Rubenson, Kjell; Desjardins, Richard

2009-01-01

Quantitative and qualitative findings on barriers to participation in adult education are reviewed and some of the defining parameters that may explain observed national differences are considered. A theoretical perspective based on bounded agency is put forth to take account of the interaction between structurally and individually based barriers…

Anomalies in Economics Enrollment: 1991-1992 to 1995-1996

ERIC Educational Resources Information Center

Lombardi, Waldo; Ramrattan, Lall B.; Szenberg, Michael

2004-01-01

This paper presents data and empirical models to explain the causes of the decline in the enrollment of economics majors during the 1991-1992 to 1995-1996 academic years. It first discusses the theoretical bases for a qualitative analysis of this type. It then discusses a sample survey methodology used to obtain cross-sectional information from…

Scaffolding Learning for Practitioner-Scholars: The Philosophy and Design of a Qualitative Research Methods Course

ERIC Educational Resources Information Center

Slayton, Julie; Samkian, Artineh

2017-01-01

We present our approach to a qualitative research methods course to prepare practitioner-scholars for their dissertation and independent research. We explain how an instructor's guide provides consistency and rigor, and in-class activities to scaffold learning, and helps faculty connect the content to students' out-of-school lives. We explain how…

Ferromagnetic ordering in Mn-doped quantum wells GaAs-AlGaAs resulting from the virtual Anderson transition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agrinskaya, N. V.; Berezovets, V. A.; Bouravlev, A.

We present our results obtained for Mn-doped GaAs quantum wells where the evidences of the ferromagnetic transition at relatively high temperatures were found at unusually small Mn concentrations. The observed values of hopping resistance at small temperatures evidenced that the samples are deep in the insulating regime. Thus the corresponding estimates of the overlapping integrals can hardly explain the large values of Curie temperatures T{sub c} ≃ 100 K. We develop a theoretical model qualitatively explaining the experimental results basing on the concept of virtual Anderson transition.

Isoscalar-isovector mass splittings in excited mesons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geiger, P.

1994-06-01

Mass splittings between the isovector and isoscalar members of meson nonets arise in part from hadronic loop diagrams which violate the Okubo-Zweig-Iizuka rule. Using a model for these loop processes which works qualitatively well in the established nonets, I tabulate predictions for the splittings and associated isoscalar mixing angles in the remaining nonets below about 2 GeV, and explain some of their systematic features. The model predicts significant deviations from ideal mixing in the excited vector nonets.

Generation of net sediment transport by velocity skewness in oscillatory sheet flow

NASA Astrophysics Data System (ADS)

Chen, Xin; Li, Yong; Chen, Genfa; Wang, Fujun; Tang, Xuelin

2018-01-01

This study utilizes a qualitative approach and a two-phase numerical model to investigate net sediment transport caused by velocity skewness beneath oscillatory sheet flow and current. The qualitative approach is derived based on the pseudo-laminar approximation of boundary layer velocity and exponential approximation of concentration. The two-phase model can obtain well the instantaneous erosion depth, sediment flux, boundary layer thickness, and sediment transport rate. It can especially illustrate the difference between positive and negative flow stages caused by velocity skewness, which is considerably important in determining the net boundary layer flow and sediment transport direction. The two-phase model also explains the effect of sediment diameter and phase-lag to sediment transport by comparing the instantaneous-type formulas to better illustrate velocity skewness effect. In previous studies about sheet flow transport in pure velocity-skewed flows, net sediment transport is only attributed to the phase-lag effect. In the present study with the qualitative approach and two-phase model, phase-lag effect is shown important but not sufficient for the net sediment transport beneath pure velocity-skewed flow and current, while the asymmetric wave boundary layer development between positive and negative flow stages also contributes to the sediment transport.

Continuous Measurements and Quantitative Constraints: Challenge Problems for Discrete Modeling Techniques

NASA Technical Reports Server (NTRS)

Goodrich, Charles H.; Kurien, James; Clancy, Daniel (Technical Monitor)

2001-01-01

We present some diagnosis and control problems that are difficult to solve with discrete or purely qualitative techniques. We analyze the nature of the problems, classify them and explain why they are frequently encountered in systems with closed loop control. This paper illustrates the problem with several examples drawn from industrial and aerospace applications and presents detailed information on one important application: In-Situ Resource Utilization (ISRU) on Mars. The model for an ISRU plant is analyzed showing where qualitative techniques are inadequate to identify certain failure modes and to maintain control of the system in degraded environments. We show why the solution to the problem will result in significantly more robust and reliable control systems. Finally, we illustrate requirements for a solution to the problem by means of examples.

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

PubMed Central

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

2016-01-01

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

The abnormal electrical and optical properties in Na and Ni codoped BiFeO{sub 3} nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Xunling; Liu, Weifang, E-mail: wfliu@tju.edu.cn, E-mail: shouyu.wang@yahoo.com; Zhang, Hong

2015-05-07

Bi{sub 0.97}Na{sub 0.03}Fe{sub 1−x}Ni{sub x}O{sub 3} (x = 0, 0.005, 0.01, 0.015) nanoparticles are prepared via a sol-gel method. Weak ferromagnetism and exchange bias phenomenon without field cooling are observed in the samples. The oxygen vacancy concentration and leakage current density are increased with increasing the Ni content. However, with the increase of Ni content, the band gap of Bi{sub 0.97}Na{sub 0.03}Fe{sub 1−x}Ni{sub x}O{sub 3} nanoparticles first decreases and then increases. To explain the abnormal phenomenon, the interplay of oxygen vacancy donor and hole acceptor is analyzed and a phenomenological qualitative model based on the electronic energy band is proposed. Additionally, themore » threshold switching behavior appears in Bi{sub 0.97}Na{sub 0.03}Fe{sub 1−x}Ni{sub x}O{sub 3} samples with x = 0.01, 0.015 and the effect is qualitatively explained by introducing a conducting channel model based on the high-density mobile charges.« less

The Early Spectra of Eta Carinae 1892 to 1941 and the Onset of its High Excitation Emission Spectrum

NASA Astrophysics Data System (ADS)

Humphreys, Roberta M.; Davidson, Kris; Koppelman, Michael

2008-04-01

The observed behavior of η Car from 1860 to 1940 has not been considered in most recent accounts, nor has it been explained in any quantitative model. We have used modern digital processing techniques to examine Harvard objective-prism spectra made from 1892 to 1941. Relatively high excitation He I λ4471 and [Fe III] λ4658 emission, conspicuous today, were weak and perhaps absent throughout those years. Feast et al. noted this qualitative fact for other pre-1920 spectra, but we quantify it and extend it to a time only three years before Gaviola's first observations of the high-excitation features. Evidently the supply of helium-ionizing photons (λ < 504 Å) grew rapidly between 1941 and 1944. The apparent scarcity of such far-UV radiation before 1944 is difficult to explain in models that employ a hot massive secondary star, because no feasible dense wind or obscuration by dust would have hidden the photoionization caused by the proposed companion during most of its orbital period. We also discuss the qualitative near-constancy of the spectrum from 1900 to 1940, and η Car's photometric and spectroscopic transition between 1940 and 1953.

The planetary increase of brightness during retrograde motion: An explanandum constructed ad explanantem.

PubMed

Carman, Christián Carlos

2015-12-01

In Ancient Greek two models were proposed for explaining the planetary motion: the homocentric spheres of Eudoxus and the Epicycle and Deferent System. At least in a qualitative way, both models could explain the retrograde motion, the most challenging phenomenon to be explained using circular motions. Nevertheless, there is another explanandum: during retrograde motion the planets increase their brightness. It is natural to interpret a change of brightness, i.e., of apparent size, as a change in distance. Now, while according to the Eudoxian model the planet is always equidistant from the earth, according to the epicycle and deferent system, the planet changes its distance from the earth, approaching to it during retrograde motion, just as observed. So, it is usually affirmed that the main reason for the rejection of Eudoxus' homocentric spheres in favor of the epicycle and deferent system was that the first cannot explain the manifest planetary increase of brightness during retrograde motion, while the second can. In this paper I will show that this historical hypothesis is not as firmly founded as it is usually believed to be. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling a space-variant cortical representation for apparent motion.

PubMed

Wurbs, Jeremy; Mingolla, Ennio; Yazdanbakhsh, Arash

2013-08-06

Receptive field sizes of neurons in early primate visual areas increase with eccentricity, as does temporal processing speed. The fovea is evidently specialized for slow, fine movements while the periphery is suited for fast, coarse movements. In either the fovea or periphery discrete flashes can produce motion percepts. Grossberg and Rudd (1989) used traveling Gaussian activity profiles to model long-range apparent motion percepts. We propose a neural model constrained by physiological data to explain how signals from retinal ganglion cells to V1 affect the perception of motion as a function of eccentricity. Our model incorporates cortical magnification, receptive field overlap and scatter, and spatial and temporal response characteristics of retinal ganglion cells for cortical processing of motion. Consistent with the finding of Baker and Braddick (1985), in our model the maximum flash distance that is perceived as an apparent motion (Dmax) increases linearly as a function of eccentricity. Baker and Braddick (1985) made qualitative predictions about the functional significance of both stimulus and visual system parameters that constrain motion perception, such as an increase in the range of detectable motions as a function of eccentricity and the likely role of higher visual processes in determining Dmax. We generate corresponding quantitative predictions for those functional dependencies for individual aspects of motion processing. Simulation results indicate that the early visual pathway can explain the qualitative linear increase of Dmax data without reliance on extrastriate areas, but that those higher visual areas may serve as a modulatory influence on the exact Dmax increase.

The role of empathy and emotional intelligence in nurses' communication attitudes using regression models and fuzzy-set qualitative comparative analysis models.

PubMed

Giménez-Espert, María Del Carmen; Prado-Gascó, Vicente Javier

2018-03-01

To analyse link between empathy and emotional intelligence as a predictor of nurses' attitudes towards communication while comparing the contribution of emotional aspects and attitudinal elements on potential behaviour. Nurses' attitudes towards communication, empathy and emotional intelligence are key skills for nurses involved in patient care. There are currently no studies analysing this link, and its investigation is needed because attitudes may influence communication behaviours. Correlational study. To attain this goal, self-reported instruments (attitudes towards communication of nurses, trait emotional intelligence (Trait Emotional Meta-Mood Scale) and Jefferson Scale of Nursing Empathy (Jefferson Scale Nursing Empathy) were collected from 460 nurses between September 2015-February 2016. Two different analytical methodologies were used: traditional regression models and fuzzy-set qualitative comparative analysis models. The results of the regression model suggest that cognitive dimensions of attitude are a significant and positive predictor of the behavioural dimension. The perspective-taking dimension of empathy and the emotional-clarity dimension of emotional intelligence were significant positive predictors of the dimensions of attitudes towards communication, except for the affective dimension (for which the association was negative). The results of the fuzzy-set qualitative comparative analysis models confirm that the combination of high levels of cognitive dimension of attitudes, perspective-taking and emotional clarity explained high levels of the behavioural dimension of attitude. Empathy and emotional intelligence are predictors of nurses' attitudes towards communication, and the cognitive dimension of attitude is a good predictor of the behavioural dimension of attitudes towards communication of nurses in both regression models and fuzzy-set qualitative comparative analysis. In general, the fuzzy-set qualitative comparative analysis models appear to be better predictors than the regression models are. To evaluate current practices, establish intervention strategies and evaluate their effectiveness. The evaluation of these variables and their relationships are important in creating a satisfied and sustainable workforce and improving quality of care and patient health. © 2018 John Wiley & Sons Ltd.

Theory of concentration dependence in drag reduction by polymers and of the maximum drag reduction asymptote.

PubMed

Benzi, Roberto; Ching, Emily S C; Horesh, Nizan; Procaccia, Itamar

2004-02-20

A simple model of the effect of polymer concentration on the amount of drag reduction in turbulence is presented, simulated, and analyzed. The qualitative phase diagram of drag coefficient versus Reynolds number (Re) is recaptured in this model, including the theoretically elusive onset of drag reduction and the maximum drag reduction (MDR) asymptote. The Re-dependent drag and the MDR are analytically explained, and the dependence of the amount of drag on material parameters is rationalized.

Deposing the Cool Corona of KPD 0005+5106

NASA Astrophysics Data System (ADS)

Werner, K.; Drake, J. J.

2005-07-01

We show that the Chandra LETG spectrum of the hottest known DO white dwarf, KPD 0005+5106, can be qualitatively modelled as photospheric emission, and does not require a coronal explanation. The excess flux found by Fleming et al. (1993) in the 0.2-0.3 keV region arises from deeper atmospheric layers revealed by a lower continuous opacity in this region. The 1 keV emission found by O'Dwyer et al. (2003) lies below our detection threshold, but cannot be explained by photospheric models.

A qualitative evidence synthesis of employees’ views of workplace smoking reduction or cessation interventions

PubMed Central

2013-01-01

Background The need to reduce smoking rates is a recognised public health policy issue in many countries. The workplace offers a potential context for offering smokers’ programmes and interventions to assist smoking cessation or reduction. A qualitative evidence synthesis of employees’ views about such programmes might explain why some interventions appear effective and others not, and can be used to develop evidence-based interventions for this population and setting. Methods A qualitative evidence synthesis of primary research exploring employees’ views about workplace interventions to encourage smoking cessation, including both voluntary programmes and passive interventions, such as restrictions or bans. The method used was theory-based “best fit” framework synthesis. Results Five relevant theories on workplace smoking cessation were identified and used as the basis for an a priori framework. A comprehensive literature search, including interrogation of eight databases, retrieved 747 unique citations for the review. Fifteen primary research studies of qualitative evidence were found to satisfy the inclusion criteria. The synthesis produced an evidence-based conceptual model explaining employees’ experiences of, and preferences regarding, workplace smoking interventions. Conclusion The synthesis suggests that workplace interventions should employ a range of different elements if they are to prove effective in reducing smoking among employees. This is because an employee who feels ready and able to change their behaviour has different needs and preferences from an employee who is not at that stage. Only a multi-faceted intervention can satisfy the requirements of all employees. PMID:24274158

A model of cell wall expansion based on thermodynamics of polymer networks

NASA Technical Reports Server (NTRS)

Veytsman, B. A.; Cosgrove, D. J.

1998-01-01

A theory of cell wall extension is proposed. It is shown that macroscopic properties of cell walls can be explained through the microscopic properties of interpenetrating networks of cellulose and hemicellulose. The qualitative conclusions of the theory agree with the existing experimental data. The dependence of the cell wall yield threshold on the secretion of the wall components is discussed.

“Best fit” framework synthesis: refining the method

PubMed Central

2013-01-01

Background Following publication of the first worked example of the “best fit” method of evidence synthesis for the systematic review of qualitative evidence in this journal, the originators of the method identified a need to specify more fully some aspects of this particular derivative of framework synthesis. Methods and Results We therefore present a second such worked example in which all techniques are defined and explained, and their appropriateness is assessed. Specified features of the method include the development of new techniques to identify theories in a systematic manner; the creation of an a priori framework for the synthesis; and the “testing” of the synthesis. An innovative combination of existing methods of quality assessment, analysis and synthesis is used to complete the process. This second worked example was a qualitative evidence synthesis of employees’ views of workplace smoking cessation interventions, in which the “best fit” method was found to be practical and fit for purpose. Conclusions The method is suited to producing context-specific conceptual models for describing or explaining the decision-making and health behaviours of patients and other groups. It offers a pragmatic means of conducting rapid qualitative evidence synthesis and generating programme theories relating to intervention effectiveness, which might be of relevance both to researchers and policy-makers. PMID:23497061

Dynamics of Whistler-mode Waves Below LHR Frequency: Application for the Equatorial Noise

NASA Astrophysics Data System (ADS)

Balikhin, M. A.; Shklyar, D. R.

2017-12-01

Plasma waves that are regularly observed in the vicinity of geomagnetic equator since 1970's are often referred to as "equatorial noise" or "equatorial magnetosonic" emission. Currently, it is accepted that these waves can have significant effects on both the processes of loss and acceleration of energetic electrons within the radiation belts. A model to explain the observed features of the equatorial noise is presented. It is assumed that the loss-cone instability of supra-thermal ions is the reason for their generation. It is argued that as these waves propagate their growth/damping rate changes and, therefore the integral wave amplification is more important to explain observed spectral features than the local growth rate. The qualitative correspondence of Cluster observations with dynamical spectra arising from the model is shown.

Defects Induced Enhancement of Eu3+ Emission in Yttria ( Y2O3:Eu3+)

NASA Astrophysics Data System (ADS)

Jagannathan, R.; Kutty, T.; Kottaisamy, M.; Jeyagopal, P.

1994-11-01

Bixbyite type Y2O3:Eu3+ apart from being the efficient red phosphor extensively used in trichromatic fluorescent lamps, it is a typical system one can apply Jørgensen's refined electron spin pairing theory. This can be used to explain the enhancement in Eu3+ emission intensity observed with the aliovalent substitution in the yttria host matrix. Results based on these are explained qualitatively by considering a simple configurational coordinate model. Futhermore, an insight into the different types of defects induced with the aliovalent substitution in the yttria lattice has become possible with EPR probe.

Swiss Armed Forces Organizational Level Leader Development: A Qualitative Case Study

DTIC Science & Technology

2017-06-09

chapter, divided in five distinct parts, describes the chosen research methodology , explain why the qualitative case study is appropriate to conduct...research study uses a qualitative methodology by performing a qualitative case study on the organizational level leader’s development process within...develop an in-depth understsanding of the phenomen.”82 Summary This research study uses a qualitative methodology by performing a case study on the

Utility of qualitative methods in a clinical setting: perinatal care in the Western Province.

PubMed

Jayasuriya, V

2012-03-01

A peculiar paradox that has been observed in previous studies of antenatal care is where patients are satisfied with the services despite obvious lack of basic facilities. Qualitative methods were used to describe the experience of perinatal care in the Western province with the objective of demonstrating application of this method in a clinical setting. This paper used a 'naturalistic' approach of qualitative methods. In-depth interviews conducted with 20 postnatal mothers delivering in tertiary care institutions in the Western province was tape recorded, transcribed and content analysed. To ensure objectivity and validity of results, the principle investigator received only the anonymised data to prevent any prejudices or pre-conceptions affecting the results. The main themes emerging from the text demonstrated 'naïve trust' in the carer and a state of 'hero worship' where patients were distanced and therefore unable and unwilling to query the decisions made by the carers. This is similar to a state of patient-carer relationship described in a published model known as guarded alliance, where the relationship develops though four phases based on the level of trust and confidence in the relationship. This state explains not only why patients fail to recognise and report any deficiencies in the services but also the need for them to justify the behaviour of caregivers even when it amounts to incompetence and negligence. Qualitative methods allow the researcher to capture experiences in its 'natural' form rather than based on pre-determined protocols or plans, which may be limited to our own understanding and expectations and therefore unable to explain many idiosyncrasies of the programmes. This paper argues favourably for the use of qualitative methods in other clinical settings.

Grounded theory as a method for research in speech and language therapy.

PubMed

Skeat, J; Perry, A

2008-01-01

The use of qualitative methodologies in speech and language therapy has grown over the past two decades, and there is now a body of literature, both generally describing qualitative research, and detailing its applicability to health practice(s). However, there has been only limited profession-specific discussion of qualitative methodologies and their potential application to speech and language therapy. To describe the methodology of grounded theory, and to explain how it might usefully be applied to areas of speech and language research where theoretical frameworks or models are lacking. Grounded theory as a methodology for inductive theory-building from qualitative data is explained and discussed. Some differences between 'modes' of grounded theory are clarified and areas of controversy within the literature are highlighted. The past application of grounded theory to speech and language therapy, and its potential for informing research and clinical practice, are examined. This paper provides an in-depth critique of a qualitative research methodology, including an overview of the main difference between two major 'modes'. The article supports the application of a theory-building approach in the profession, which is sometimes complex to learn and apply, but worthwhile in its results. Grounded theory as a methodology has much to offer speech and language therapists and researchers. Although the majority of research and discussion around this methodology has rested within sociology and nursing, grounded theory can be applied by researchers in any field, including speech and language therapists. The benefit of the grounded theory method to researchers and practitioners lies in its application to social processes and human interactions. The resulting theory may support further research in the speech and language therapy profession.

Use of theoretical and conceptual frameworks in qualitative research.

PubMed

Green, Helen Elise

2014-07-01

To debate the definition and use of theoretical and conceptual frameworks in qualitative research. There is a paucity of literature to help the novice researcher to understand what theoretical and conceptual frameworks are and how they should be used. This paper acknowledges the interchangeable usage of these terms and researchers' confusion about the differences between the two. It discusses how researchers have used theoretical and conceptual frameworks and the notion of conceptual models. Detail is given about how one researcher incorporated a conceptual framework throughout a research project, the purpose for doing so and how this led to a resultant conceptual model. Concepts from Abbott (1988) and Witz ( 1992 ) were used to provide a framework for research involving two case study sites. The framework was used to determine research questions and give direction to interviews and discussions to focus the research. Some research methods do not overtly use a theoretical framework or conceptual framework in their design, but this is implicit and underpins the method design, for example in grounded theory. Other qualitative methods use one or the other to frame the design of a research project or to explain the outcomes. An example is given of how a conceptual framework was used throughout a research project. Theoretical and conceptual frameworks are terms that are regularly used in research but rarely explained. Textbooks should discuss what they are and how they can be used, so novice researchers understand how they can help with research design. Theoretical and conceptual frameworks need to be more clearly understood by researchers and correct terminology used to ensure clarity for novice researchers.

One Giant Leap for Categorizers: One Small Step for Categorization Theory

PubMed Central

Smith, J. David; Ell, Shawn W.

2015-01-01

We explore humans’ rule-based category learning using analytic approaches that highlight their psychological transitions during learning. These approaches confirm that humans show qualitatively sudden psychological transitions during rule learning. These transitions contribute to the theoretical literature contrasting single vs. multiple category-learning systems, because they seem to reveal a distinctive learning process of explicit rule discovery. A complete psychology of categorization must describe this learning process, too. Yet extensive formal-modeling analyses confirm that a wide range of current (gradient-descent) models cannot reproduce these transitions, including influential rule-based models (e.g., COVIS) and exemplar models (e.g., ALCOVE). It is an important theoretical conclusion that existing models cannot explain humans’ rule-based category learning. The problem these models have is the incremental algorithm by which learning is simulated. Humans descend no gradient in rule-based tasks. Very different formal-modeling systems will be required to explain humans’ psychology in these tasks. An important next step will be to build a new generation of models that can do so. PMID:26332587

Qualitative Shadowing as a Research Methodology for Exploring Early Childhood Leadership in Practice

ERIC Educational Resources Information Center

Bøe, Marit; Hognestad, Karin; Waniganayake, Manjula

2017-01-01

This article explores qualitative shadowing as an interpretivist methodology, and explains how two researchers participating simultaneously in data collection using a video recorder, contextual interviews and video-stimulated recall interviews, conducted a qualitative shadowing study at six early childhood centres in Norway. This paper emerged…

Simulation of electron transport in quantum well devices

NASA Technical Reports Server (NTRS)

Miller, D. R.; Gullapalli, K. K.; Reddy, V. R.; Neikirk, D. P.

1992-01-01

Double barrier resonant tunneling diodes (DBRTD) have received much attention as possible terahertz devices. Despite impressive experimental results, the specifics of the device physics (i.e., how the electrons propagate through the structure) are only qualitatively understood. Therefore, better transport models are warranted if this technology is to mature. In this paper, the Lattice Wigner function is used to explain the important transport issues associated with DBRTD device behavior.

A model of the pre-assessment learning effects of assessment is operational in an undergraduate clinical context

PubMed Central

2012-01-01

Background No validated model exists to explain the learning effects of assessment, a problem when designing and researching assessment for learning. We recently developed a model explaining the pre-assessment learning effects of summative assessment in a theory teaching context. The challenge now is to validate this model. The purpose of this study was to explore whether the model was operational in a clinical context as a first step in this process. Methods Given the complexity of the model, we adopted a qualitative approach. Data from in-depth interviews with eighteen medical students were subject to content analysis. We utilised a code book developed previously using grounded theory. During analysis, we remained alert to data that might not conform to the coding framework and open to the possibility of deploying inductive coding. Ethical clearance and informed consent were obtained. Results The three components of the model i.e., assessment factors, mechanism factors and learning effects were all evident in the clinical context. Associations between these components could all be explained by the model. Interaction with preceptors was identified as a new subcomponent of assessment factors. The model could explain the interrelationships of the three facets of this subcomponent i.e., regular accountability, personal consequences and emotional valence of the learning environment, with previously described components of the model. Conclusions The model could be utilized to analyse and explain observations in an assessment context different to that from which it was derived. In the clinical setting, the (negative) influence of preceptors on student learning was particularly prominent. In this setting, learning effects resulted not only from the high-stakes nature of summative assessment but also from personal stakes, e.g. for esteem and agency. The results suggest that to influence student learning, consequences should accrue from assessment that are immediate, concrete and substantial. The model could have utility as a planning or diagnostic tool in practice and research settings. PMID:22420839

The impact of conveying the diagnosis when using a biopsychosocial approach: A qualitative study among adolescents and young adults with NES (non-epileptic seizures).

PubMed

Karterud, Hilde Nordahl; Risør, Mette Bech; Haavet, Ole Rikard

2015-01-01

This qualitative study explored the impact of using a biopsychosocial approach to explain the diagnosis of non-epileptic seizures (NES). Semi-structured interviews of eleven adolescents and young adults who had participated in an inpatient follow-up stay of the diagnosis were used. The interviews were taped, transcribed, and analysed using systematic text condensation. Three key themes were identified:1."Threatened self-image": Patients initially perceived their diagnosis as being purely psychological. As they did not accept that they had mental disorders, they interpreted this as frightening and threatening, and resisted the diagnosis.2."Being believed and belief in oneself": Participants had many experiences of being suspected by healthcare providers of staging their seizures. Some had even begun to have doubts themselves as to whether the attacks were voluntary or not. Explaining that unconscious processes are involved in NES contributed towards increasing patients' feelings of being believed, and thereby acceptance of the diagnosis.3."Getting an explanation that makes sense": Some participants identified connections between their personal histories and their seizures and became seizure-free. Others found that the explanatory models gave personal meaning, but did not become seizure-free, while a few continued to doubt whether NES was the correct diagnosis. Being believed was the most elemental factor for coping with the condition. Using a biopsychosocial approach to explain the diagnosis may facilitate identification with the explanatory models, and thus acceptance of the diagnosis. Copyright © 2014 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Ion conduction in the KcsA potassium channel analyzed with a minimal kinetic model.

PubMed

Mafé, Salvador; Pellicer, Julio

2005-02-01

We use a model by Nelson to study the current-voltage and conductance-concentration curves of bacterial potassium channel KcsA without assuming rapid ion translocation. Ion association to the channel filter is rate controlling at low concentrations, but dissociation and transport in the filter can limit conduction at high concentration for ions other than K+. The absolute values of the effective rate constants are tentative but the relative changes in these constants needed to qualitatively explain the experiments should be of significance.

Molecular-orbital model for metal-sapphire interfacial strength

NASA Technical Reports Server (NTRS)

Johnson, K. H.; Pepper, S. V.

1982-01-01

Self-consistent-field X-Alpha scattered-wave cluster molecular-orbital models have been constructed for transition and noble metals (Fe, Ni, Cu, and Ag) in contact with a sapphire (Al2O3) surface. It is found that a chemical bond is established between the metal d-orbital electrons and the nonbonding 2p-orbital electrons of the oxygen anions on the Al2O3 surface. An increasing number of occupied metal-sapphire antibonding molecular orbitals explains qualitatively the observed decrease of contact shear strength through the series Fe, Ni, Cu, and Ag.

The Use of a Checklist and Qualitative Notebooks for an Interactive Process of Teaching and Learning Qualitative Research

ERIC Educational Resources Information Center

Frels, Rebecca K.; Sharma, Bipin; Onwuegbuzie, Anthony J.; Leech, Nancy L.; Stark, Marcella D.

2011-01-01

From the perspective of doctoral students and instructors, we explain a developmental, interactive process based upon the Checklist for Qualitative Data Collection, Data Analysis, and Data Interpretation (Onwuegbuzie, 2010) for students' writing assignments regarding: (a) the application of conceptual knowledge for collecting, analyzing, and…

An Analytical Diffusion–Expansion Model for Forbush Decreases Caused by Flux Ropes

NASA Astrophysics Data System (ADS)

Dumbović, Mateja; Heber, Bernd; Vršnak, Bojan; Temmer, Manuela; Kirin, Anamarija

2018-06-01

We present an analytical diffusion–expansion Forbush decrease (FD) model ForbMod, which is based on the widely used approach of an initially empty, closed magnetic structure (i.e., flux rope) that fills up slowly with particles by perpendicular diffusion. The model is restricted to explaining only the depression caused by the magnetic structure of the interplanetary coronal mass ejection (ICME). We use remote CME observations and a 3D reconstruction method (the graduated cylindrical shell method) to constrain initial boundary conditions of the FD model and take into account CME evolutionary properties by incorporating flux rope expansion. Several flux rope expansion modes are considered, which can lead to different FD characteristics. In general, the model is qualitatively in agreement with observations, whereas quantitative agreement depends on the diffusion coefficient and the expansion properties (interplay of the diffusion and expansion). A case study was performed to explain the FD observed on 2014 May 30. The observed FD was fitted quite well by ForbMod for all expansion modes using only the diffusion coefficient as a free parameter, where the diffusion parameter was found to correspond to an expected range of values. Our study shows that, in general, the model is able to explain the global properties of an FD caused by a flux rope and can thus be used to help understand the underlying physics in case studies.

The Stochastic Multi-strain Dengue Model: Analysis of the Dynamics

NASA Astrophysics Data System (ADS)

Aguiar, Maíra; Stollenwerk, Nico; Kooi, Bob W.

2011-09-01

Dengue dynamics is well known to be particularly complex with large fluctuations of disease incidences. An epidemic multi-strain model motivated by dengue fever epidemiology shows deterministic chaos in wide parameter regions. The addition of seasonal forcing, mimicking the vectorial dynamics, and a low import of infected individuals, which is realistic in the dynamics of infectious diseases epidemics show complex dynamics and qualitatively a good agreement between empirical DHF monitoring data and the obtained model simulation. The addition of noise can explain the fluctuations observed in the empirical data and for large enough population size, the stochastic system can be well described by the deterministic skeleton.

Spiral-syllabus course in wave phenomena to introduce majors and nonmajors to physics

NASA Astrophysics Data System (ADS)

Touger, Jerold S.

1981-09-01

A single course to introduce physics to both nonscience and physics majors has been developed, dealing with light, sound, and signal, transmission and reception, and emphasizing wave aspects of these phenomena. Themes such as the observational basis of physics, the progression from qualitative observation to measurement, physical models, mathematical modeling, and the utility of models in developing technology are stressed. Modes of presentation, consistent with the notion of a spiral syllabus, are explained with reference to the cognitive and educational theories of Bruner and Piaget. Reasons are discussed for choosing this subject matter in preference to Newtonian mechanics as a starting point for physics majors.

Solvent effects in time-dependent self-consistent field methods. I. Optical response calculations

DOE PAGES

Bjorgaard, J. A.; Kuzmenko, V.; Velizhanin, K. A.; ...

2015-01-22

In this study, we implement and examine three excited state solvent models in time-dependent self-consistent field methods using a consistent formalism which unambiguously shows their relationship. These are the linear response, state specific, and vertical excitation solvent models. Their effects on energies calculated with the equivalent of COSMO/CIS/AM1 are given for a set of test molecules with varying excited state charge transfer character. The resulting solvent effects are explained qualitatively using a dipole approximation. It is shown that the fundamental differences between these solvent models are reflected by the character of the calculated excitations.

Kinetic modeling of ion conduction in KcsA potassium channel.

PubMed

Mafé, Salvador; Pellicer, Julio; Cervera, Javier

2005-05-22

KcsA constitutes a potassium channel of known structure that shows both high conduction rates and selectivity among monovalent cations. A kinetic model for ion conduction through this channel that assumes rapid ion transport within the filter has recently been presented by Nelson. In a recent, brief communication, we used the model to provide preliminary explanations to the experimental current-voltage J-V and conductance-concentration g-S curves obtained for a series of monovalent ions (K(+),Tl(+), and Rb(+)). We did not assume rapid ion transport in the calculations, since ion transport within the selectivity filter could be rate limiting for ions other than native K(+). This previous work is now significantly extended to the following experimental problems. First, the outward rectification of the J-V curves in K(+) symmetrical solutions is analyzed using a generalized kinetic model. Second, the J-V and g-S curves for NH(4) (+) are obtained and compared with those of other ions (the NH(4) (+) J-V curve is qualitatively different from those of Rb(+) and Tl(+)). Third, the effects of Na(+) block on K(+) and Rb(+) currents through single KcsA channels are studied and the different blocking behavior is related to the values of the translocation rate constants characteristic of ion transport within the filter. Finally, the significantly decreased K(+) conductance caused by mutation of the wild-type channel is also explained in terms of this rate constant. In order to keep the number of model parameters to a minimum, we do not allow the electrical distance (an empirical parameter of kinetic models that controls the exponential voltage dependence of the dissociation rate) to vary with the ionic species. Without introducing the relatively high number of adjustable parameters of more comprehensive site-based models, we show that ion association to the filter is rate controlling at low concentrations, but ion dissociation from the filter and ion transport within the filter could limit conduction at high concentration. Although some experimental data from other authors were included to allow qualitative comparison with model calculations, the absolute values of the effective rate constants obtained are only tentative. However, the relative changes in these constants needed to explain qualitatively the experiments should be of significance.

Non-parallel coevolution of sender and receiver in the acoustic communication system of treefrogs.

PubMed

Schul, Johannes; Bush, Sarah L

2002-09-07

Advertisement calls of closely related species often differ in quantitative features such as the repetition rate of signal units. These differences are important in species recognition. Current models of signal-receiver coevolution predict two possible patterns in the evolution of the mechanism used by receivers to recognize the call: (i) classical sexual selection models (Fisher process, good genes/indirect benefits, direct benefits models) predict that close relatives use qualitatively similar signal recognition mechanisms tuned to different values of a call parameter; and (ii) receiver bias models (hidden preference, pre-existing bias models) predict that if different signal recognition mechanisms are used by sibling species, evidence of an ancestral mechanism will persist in the derived species, and evidence of a pre-existing bias will be detectable in the ancestral species. We describe qualitatively different call recognition mechanisms in sibling species of treefrogs. Whereas Hyla chrysoscelis uses pulse rate to recognize male calls, Hyla versicolor uses absolute measurements of pulse duration and interval duration. We found no evidence of either hidden preferences or pre-existing biases. The results are compared with similar data from katydids (Tettigonia sp.). In both taxa, the data are not adequately explained by current models of signal-receiver coevolution.

Champagne flutes and brandy snifters: modelling protostellar outflow-cloud chemical interfaces

NASA Astrophysics Data System (ADS)

Rollins, R. P.; Rawlings, J. M. C.; Williams, D. A.; Redman, M. P.

2014-10-01

A rich variety of molecular species has now been observed towards hot cores in star-forming regions and in the interstellar medium. An increasing body of evidence from millimetre interferometers suggests that many of these form at the interfaces between protostellar outflows and their natal molecular clouds. However, current models have remained unable to explain the origin of the observational bias towards wide-angled `brandy snifter' shaped outflows over narrower `champagne flute' shapes in carbon monoxide imaging. Furthermore, these wide-angled systems exhibit unusually high abundances of the molecular ion HCO+. We present results from a chemodynamic model of such regions where a rich chemistry arises naturally as a result of turbulent mixing between cold, dense molecular gas and the hot, ionized outflow material. The injecta drives a rich and rapid ion-neutral chemistry in qualitative and quantitative agreement with the observations. The observational bias towards wide-angled outflows is explained naturally by the geometry-dependent ion injection rate causing rapid dissociation of CO in the younger systems.

Three-dimensional Electromagnetic Modeling of the Hawaiian Swell

NASA Astrophysics Data System (ADS)

Avdeev, D.; Utada, H.; Kuvshinov, A.; Koyama, T.

2004-12-01

An anomalous behavior of the geomagnetic deep sounding (GDS) responses at the Honolulu geomagnetic observatory has been reported by many researchers. Kuvshinov et al (2004) found that the predicted GDS Dst C-response does not match the experimental data -- 10-20% disagreement occurs for all periods of 2 to 30 days, qualitatively implying a more resistive, rather than conductive, structure beneath the Hawaiian Islands. Simpson et al. (2000) found that the GDS Sq C-response at the Honolulu observatory is about 4 times larger than that at a Hawaii island site, again suggesting a more resistive (than elsewhere around) structure beneath the observatory. Constable and Heinson (2004, http://mahi.ucsd.edu/Steve/swell.pdf), presenting a 2-D interpretation of the magnetotelluric (MT) and GDS responses recently obtained at 7 seafloor sites to the south of the Hawaii Islands, concluded that the dataset require the presence of a narrow conducting plume just beneath the islands. The main motivation of our work is to reveal the reason of the anomalous behavior of the Honolulu response. Obviously, the cause may be due to heterogeneity of either the conductivity or the source field. We examine this problem in some detail with reference to the Constable and Heinson's seafloor dataset, as well as the available dataset from the Honolulu observatory. To address the problem we apply numerical modeling using the three-dimensional (3-D) forward modeling code of Avdeev et al. (1997, 2002). With this code we simulate various regional 3-D conductivity models that may produce EM responses that better fit the experimental datasets, at least qualitatively. Also, to explain some features of the experimental long-period GDS responses we numerically studied a possible effect in the responses caused by the equatorial electrojet. Our 3-D modeling results show that, in particular: (1) The GDS responses are better explained by models with a resistive lithosphere whereas the MT data are better fit by models without one; (2) A conductive plume under the Hawaiian Islands may not be required by the MT and GDS datasets considered; (3) An equatorial electrojet might affect the imaginary part of the GDS responses at periods of 2 h and more; (4) The anomalous large value of 0.4 observed in the real part of the seafloor GDS responses still cannot be explained by the 3-D models considered. It seems to require more complicated models.

A kinematic model for the late Cenozoic development of southern California crust and upper mantle

NASA Technical Reports Server (NTRS)

Humphreys, Eugene D.; Hager, Bradford H.

1990-01-01

A model is developed for the young and ongoing kinematic deformation of the southern California crust and upper mantle. The kinematic model qualitatively explains both the overall seismic structure of the upper mantle and much of the known geological history of the late Cenozoic as consequences of ongoing convection beneath southern California. In this model, the high-velocity upper-mantle anomaly of the Transverse ranges is created through the convergence and sinking of the entire thickness of subcrustal lihtosphere, and the low-velocity upper-mantle anomaly beneath the Salton Trough region is attributed to high temperatures and 1-4 percent partial melt related to adiabatic decompression during mantle upwelling.

A statistical model of aggregate fragmentation

NASA Astrophysics Data System (ADS)

Spahn, F.; Vieira Neto, E.; Guimarães, A. H. F.; Gorban, A. N.; Brilliantov, N. V.

2014-01-01

A statistical model of fragmentation of aggregates is proposed, based on the stochastic propagation of cracks through the body. The propagation rules are formulated on a lattice and mimic two important features of the process—a crack moves against the stress gradient while dissipating energy during its growth. We perform numerical simulations of the model for two-dimensional lattice and reveal that the mass distribution for small- and intermediate-size fragments obeys a power law, F(m)∝m-3/2, in agreement with experimental observations. We develop an analytical theory which explains the detected power law and demonstrate that the overall fragment mass distribution in our model agrees qualitatively with that one observed in experiments.

Tackling childhood obesity: the importance of understanding the context.

PubMed

Knai, Cécile; McKee, Martin

2010-12-01

Recommendations to tackle major health problems such as childhood obesity may not be appropriate if they fail to take account of the prevailing socio-political, cultural and economic context. We describe the development and application of a qualitative risk analysis approach to identify non-scientific considerations framing the policy response to obesity in Denmark and Latvia. Interviews conducted with key stakeholders in Denmark and Latvia, undertaken following a review of relevant literature on obesity and national policies. A qualitative risk analysis model was developed to help explain the findings in the light of national context. Non-scientific considerations that appeared to influence the response to obesity include the perceived relative importance of childhood obesity; the nature of stakeholder relations and its impact on decision-making; the place of obesity on the policy agenda; the legitimacy of the state to act for population health and views on alliances between public and private sectors. Better recognition of the exogenous factors affecting policy-making may lead to a more adequate policy response. The development and use of a qualitative risk analysis model enabled a better understanding of the contextual factors and processes influencing the response to childhood obesity in each country.

Development of metaphors to explain cognitive behavioural principles for patients with medically unexplained symptoms in Sri Lanka.

PubMed

Sumathipala, Athula

2014-03-01

Medically unexplained symptoms (MUS) are common in primary care across cultures, accounting for high consultations with multiple providers and unnecessary investigations. Cognitive behavioural therapy (CBT) is efficacious for MUS and reduces physical symptoms, psychological distress and disability. Two intervention trials by the author and his group remain the only reported trials from the developing world. A treatment package was designed by modifying a CBT model. The modifications were innovative use of locally relevant appropriate language and strategies that were simple enough while conforming to the CBT principles. The aim was to convey the principles of CBT to people using simple techniques--using metaphor. These are described in the paper as generic metaphors that could be used to explain the CBT principles and specific ones for patients with MUS. Metaphor is an effective clinical tool. The author's clinical experience and patients' feedback suggest that these metaphors are helpful in conveying the CBT principles to patients. To develop metaphors appealing to the client and effective clinically, carrying out qualitative research among patients' explanatory model is an important prerequisite. The generic and MUS-specific metaphors reported here should be tried in other cultural and clinical settings and evaluated. Further systematic work including qualitative work for consensus evaluation among CBT experts as well as opinion on user-friendliness of these techniques tested among CBT practitioners will be needed.

A century of transitions in New York City's measles dynamics.

PubMed

Hempel, Karsten; Earn, David J D

2015-05-06

Infectious diseases spreading in a human population occasionally exhibit sudden transitions in their qualitative dynamics. Previous work has successfully predicted such transitions in New York City's historical measles incidence using the seasonally forced susceptible-infectious-recovered (SIR) model. This work relied on a dataset spanning 45 years (1928-1973), which we have extended to 93 years (1891-1984). We identify additional dynamical transitions in the longer dataset and successfully explain them by analysing attractors and transients of the same mechanistic epidemiological model. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Investigation of the effect of temperature on aging behavior of Fe-doped lead zirconate titanate

NASA Astrophysics Data System (ADS)

Promsawat, Napatporn; Promsawat, Methee; Janphuang, Pattanaphong; Marungsri, Boonruang; Luo, Zhenhua; Pojprapai, Soodkhet

The aging degradation behavior of Fe-doped Lead zirconate titanate (PZT) subjected to different heat-treated temperatures was investigated over 1000h. The aging degradation in the piezoelectric properties of PZT was indicated by the decrease in piezoelectric charge coefficient, electric field-induced strain and remanent polarization. It was found that the aging degradation became more pronounced at temperature above 50% of the PZT’s Curie temperature. A mathematical model based on the linear logarithmic stretched exponential function was applied to explain the aging behavior. A qualitative aging model based on polar macrodomain switchability was proposed.

The socio-political context of migration and reproductive health disparities: The case of early sexual initiation among Mexican-origin immigrant young women

PubMed Central

Coleman-Minahan, Kate

2017-01-01

Prior research often explains the lower risk of early sexual initiation among foreign-born Mexican-origin young women by a patriarchal and sexually conservative “traditional Latino culture.” This definition overlooks structural factors such as exploitation of migrant workers, and conflates gender inequality and sexual expectations. I use an intersectional framework and the theory of gender and power to explore how gender inequality and sexual expectations are both influenced by structural factors and affect reproductive health outcomes. I integrate data from qualitative interviews with 21 first and second generation Mexican-origin women in 2013–2014 with data from discrete time hazard models with 798 Mexican-origin young women in the National Longitudinal Study of Adolescent to Adult Health. Qualitative results demonstrate that gender inequality and sexual expectations in Mexican-origin immigrant households are associated with structural factors. Gender inequality occurs more often in households with family instability, greater poverty, and among parents who migrated independently. Qualitative data also demonstrate that parental gendered expectations are sometimes at odds to what parents are actually doing in the household. Finally, contrary to assumptions that a patriarchal “traditional Latino culture” protects against early sexual initiation, qualitative and multivariate quantitative data suggest that household gender inequality increases risk of early sexual initiation. These findings challenge the utility of a culturalist approach that views culture as determining behavior to explain health disparities among immigrants and demonstrate the need to incorporate an intersectional framework that includes structural factors. This approach may reduce stereotypes and identify meaningful interventions to reduce reproductive health disparities. PMID:28324794

Health beliefs about lifestyle habits differ between patients and spouses 1 year after a cardiac event - a qualitative analysis based on the Health Belief Model.

PubMed

Köhler, Anita Kärner; Nilsson, Staffan; Jaarsma, Tiny; Tingström, Pia

2017-06-01

Spousal concordance on risk factors and lifestyle habits exists and can partly be explained by patients' and spouses' health beliefs and underuse of cardiac rehabilitation. However, there have been very few qualitative comparisons of health beliefs between patients and spouses after a cardiac event. To examine and qualitatively compare the health beliefs of patients with coronary heart disease and their spouses about lifestyle habits, 1 year after the cardiac event. Explorative and descriptive. Semi-structured focus group interviews were conducted with patients (n = 14) 1 year after a cardiac event, as well as individual interviews with spouses (n = 8). The transcriptions underwent a deductive qualitative content analysis, within the framework of the Health Belief Model. Patients' and spouses' health beliefs about lifestyle habits qualitatively differed in most predetermined main analytical categories of the Health Belief Model. The patients relied more on their own capacity and the healthcare system than on collaboration with their spouses who instead emphasised the importance of mutual activities to establish lifestyle habits. The spouses therefore experienced problems with different family preferences compared to the patients' wishes. Moreover, only patients believed supervised exercise was beneficial for risk reduction of coronary heart disease and they related barriers for medication to a self-healing body and a meaningless life without relatives and old habits. Patients and spouses agreed that despite the severity of illness, life was captured and that normalisation to a life as usual was possible. The patients' and spouses' qualitatively different health beliefs regarding health-related behaviours imply a new approach. Nurses and associated professionals need to follow-up patients' and spouses' in primary health care to support them in a tailored way, for example in problem-based sessions. Recognition and understanding of their different views and otherness could lead to compromises and goals to work with. © 2016 Nordic College of Caring Science.

Choice and Constraint in the Negotiation of the Grandparent Role: A Mixed-Methods Study.

PubMed

McGarrigle, Christine A; Timonen, Virpi; Layte, Richard

2018-01-01

Few studies have examined how the allocation and consequences of grandchild care vary across different socioeconomic groups. We analyze qualitative data alongside data from The Irish Longitudinal Study on Ageing (TILDA), in a convergent mixed-methods approach. Regression models examined characteristics associated with grandchild care, and the relationship between grandchild care and depressive symptoms and well-being. Qualitative data shed light on processes and choices that explain patterns of grandchild care provision. Tertiary-educated grandparents provided less intensive grandchild care compared with primary educated. Qualitative data indicated that this pattern stems from early boundary-drawing among higher educated grandparents while lower socioeconomic groups were constrained and less able to say no. Intensive grandchild care was associated with more depressive symptoms and lower well-being and was moderated by participation in social activities and level of education attainment. The effect of grandchild care on well-being of grandparents depends on whether it is provided by choice or obligation.

Choice and Constraint in the Negotiation of the Grandparent Role: A Mixed-Methods Study

PubMed Central

McGarrigle, Christine A.; Timonen, Virpi; Layte, Richard

2018-01-01

Few studies have examined how the allocation and consequences of grandchild care vary across different socioeconomic groups. We analyze qualitative data alongside data from The Irish Longitudinal Study on Ageing (TILDA), in a convergent mixed-methods approach. Regression models examined characteristics associated with grandchild care, and the relationship between grandchild care and depressive symptoms and well-being. Qualitative data shed light on processes and choices that explain patterns of grandchild care provision. Tertiary-educated grandparents provided less intensive grandchild care compared with primary educated. Qualitative data indicated that this pattern stems from early boundary-drawing among higher educated grandparents while lower socioeconomic groups were constrained and less able to say no. Intensive grandchild care was associated with more depressive symptoms and lower well-being and was moderated by participation in social activities and level of education attainment. The effect of grandchild care on well-being of grandparents depends on whether it is provided by choice or obligation. PMID:29372176

Modeling Addictive Consumption as an Infectious Disease*

PubMed Central

Alamar, Benjamin; Glantz, Stanton A.

2011-01-01

The dominant model of addictive consumption in economics is the theory of rational addiction. The addict in this model chooses how much they are going to consume based upon their level of addiction (past consumption), the current benefits and all future costs. Several empirical studies of cigarette sales and price data have found a correlation between future prices and consumption and current consumption. These studies have argued that the correlation validates the rational addiction model and invalidates any model in which future consumption is not considered. An alternative to the rational addiction model is one in which addiction spreads through a population as if it were an infectious disease, as supported by the large body of empirical research of addictive behaviors. In this model an individual's probability of becoming addicted to a substance is linked to the behavior of their parents, friends and society. In the infectious disease model current consumption is based only on the level of addiction and current costs. Price and consumption data from a simulation of the infectious disease model showed a qualitative match to the results of the rational addiction model. The infectious disease model can explain all of the theoretical results of the rational addiction model with the addition of explaining initial consumption of the addictive good. PMID:21339848

Qualitative interviews in medical research.

PubMed Central

Britten, N.

1995-01-01

Much qualitative research is interview based, and this paper provides an outline of qualitative interview techniques and their application in medical settings. It explains the rationale for these techniques and shows how they can be used to research kinds of questions that are different from those dealt with by quantitative methods. Different types of qualitative interviews are described, and the way in which they differ from clinical consultations is emphasised. Practical guidance for conducting such interviews is given. Images p252-a PMID:7627048

The Health Belief Model: A Qualitative Study to Understand High-risk Sexual Behavior in Chinese Men Who Have Sex With Men.

PubMed

Li, Xianhong; Lei, Yunxiao; Wang, Honghong; He, Guoping; Williams, Ann Bartley

2016-01-01

The Health Belief Model (HBM) has been widely used to explain rationales for health risk-taking behaviors. Our qualitative study explored the applicability of the HBM to understand high-risk sexual behavior in Chinese men who have sex with men (MSM) and to elaborate each component of the model. HIV knowledge and perception of HIV prevalence contributed to perceived susceptibility. An attitude of treatment optimism versus hard life in reality affected perceived severity. Perceived barriers included discomfort using condoms and condom availability. Perceived benefits included prevention of HIV and other sexually transmitted illnesses. Sociocultural cues for Chinese MSM were elaborated according to each component. The results demonstrated that the HBM could be applied to Chinese MSM. When used with this group, it provided information to help develop a population- and disease-specific HBM scale. Results of our study also suggested behavioral interventions that could be used with Chinese MSM to increase condom use. Copyright © 2016 Association of Nurses in AIDS Care. All rights reserved.

Retrograde motion of a rolling disk

NASA Astrophysics Data System (ADS)

Borisov, A. V.; Kilin, A. A.; Karavaev, Yu L.

2017-12-01

This paper presents results of theoretical and experimental research explaining the retrograde final-stage rolling of a disk under certain relations between its mass and geometric parameters. Modifying the no-slip model of a rolling disk by including viscous rolling friction provides a qualitative explanation for the disk’s retrograde motion. At the same time, the simple experiments described in the paper completely reject the aerodynamical drag torque as a key reason for the retro-grade motion of a disk considered, thus disproving some recent hypotheses.

Analysis of asymmetric property with DC bias current on thin-film magnetoimpedance element

NASA Astrophysics Data System (ADS)

Kikuchi, Hiroaki; Sumida, Chihiro

2018-05-01

We theoretically analyzed the magnetoimpedance profile of a thin-film element with a DC bias current using the bias susceptibility theory and Maxwell's equations. Although the analysis model predicts that an element with a rectangular cross section shows symmetric impedance property with respect to the Z-axis with DC bias current, the experimental results showed asymmetric properties. Taking the shape imbalance and trapezoidal cross section of the element into account, we explained the asymmetric impedance properties qualitatively.

Choices and changes: Eccles' Expectancy-Value model and upper-secondary school students' longitudinal reflections about their choice of a STEM education

NASA Astrophysics Data System (ADS)

Lykkegaard, Eva; Ulriksen, Lars

2016-03-01

During the past 30 years, Eccles' comprehensive social-psychological Expectancy-Value Model of Motivated Behavioural Choices (EV-MBC model) has been proven suitable for studying educational choices related to Science, Technology, Engineering and/or Mathematics (STEM). The reflections of 15 students in their last year in upper-secondary school concerning their choice of tertiary education were examined using quantitative EV-MBC surveys and repeated qualitative interviews. This article presents the analyses of three cases in detail. The analytical focus was whether the factors indicated in the EV-MBC model could be used to detect significant changes in the students' educational choice processes. An important finding was that the quantitative EV-MBC surveys and the qualitative interviews gave quite different results concerning the students' considerations about the choice of tertiary education, and that significant changes in the students' reflections were not captured by the factors of the EV-MBC model. This questions the validity of the EV-MBC surveys. Moreover, the quantitative factors from the EV-MBC model did not sufficiently explain students' dynamical educational choice processes where students in parallel considered several different potential educational trajectories. We therefore call for further studies of the EV-MBC model's use in describing longitudinal choice processes and especially in investigating significant changes.

An exploratory sequential design to validate measures of moral emotions.

PubMed

Márquez, Margarita G; Delgado, Ana R

2017-05-01

This paper presents an exploratory and sequential mixed methods approach in validating measures of knowledge of the moral emotions of contempt, anger and disgust. The sample comprised 60 participants in the qualitative phase when a measurement instrument was designed. Item stems, response options and correction keys were planned following the results obtained in a descriptive phenomenological analysis of the interviews. In the quantitative phase, the scale was used with a sample of 102 Spanish participants, and the results were analysed with the Rasch model. In the qualitative phase, salient themes included reasons, objects and action tendencies. In the quantitative phase, good psychometric properties were obtained. The model fit was adequate. However, some changes had to be made to the scale in order to improve the proportion of variance explained. Substantive and methodological im-plications of this mixed-methods study are discussed. Had the study used a single re-search method in isolation, aspects of the global understanding of contempt, anger and disgust would have been lost.

A simple microstructure return model explaining microstructure noise and Epps effects

NASA Astrophysics Data System (ADS)

Saichev, A.; Sornette, D.

2014-01-01

We present a novel simple microstructure model of financial returns that combines (i) the well-known ARFIMA process applied to tick-by-tick returns, (ii) the bid-ask bounce effect, (iii) the fat tail structure of the distribution of returns and (iv) the non-Poissonian statistics of inter-trade intervals. This model allows us to explain both qualitatively and quantitatively important stylized facts observed in the statistics of both microstructure and macrostructure returns, including the short-ranged correlation of returns, the long-ranged correlations of absolute returns, the microstructure noise and Epps effects. According to the microstructure noise effect, volatility is a decreasing function of the time-scale used to estimate it. The Epps effect states that cross correlations between asset returns are increasing functions of the time-scale at which the returns are estimated. The microstructure noise is explained as the result of the negative return correlations inherent in the definition of the bid-ask bounce component (ii). In the presence of a genuine correlation between the returns of two assets, the Epps effect is due to an average statistical overlap of the momentum of the returns of the two assets defined over a finite time-scale in the presence of the long memory process (i).

Confidence in word detection predicts word identification: implications for an unconscious perception paradigm.

PubMed

Haase, S J; Fisk, G

2001-01-01

The present experiments extend the scope of the independent observation model based on signal detection theory (Macmillan & Creelman, 1991) to complex (word) stimulus sets. In the first experiment, the model predicts the relationship between uncertain detection and subsequent correct identification, thereby providing an alternative interpretation to a phenomenon often described as unconscious perception. Our second experiment used an exclusion task (Jacoby, Toth, & Yonelinas, 1993), which, according to theories of unconscious perception, should show qualitative differences in performance based on stimulus detection accuracy and provide a relative measure of conscious versus unconscious influences (Merikle, Joordens, & Stoltz, 1995). Exclusion performance was also explained by the model, suggesting that undetected words did not unconsciously influence identification responses.

Particle drift model for Z-pinch-driven magneto-Rayleigh-Taylor instability

NASA Astrophysics Data System (ADS)

Dan, Jia Kun; Xu, Qiang; Wang, Kun Lun; Ren, Xiao Dong; Huang, Xian Bin

2016-09-01

A theoretical model of Z-pinch driven magneto-Rayleigh-Taylor instability is proposed based on the particle drift point of view, which can explain the helical instability structure observed in premagnetized imploding liner experiments. It is demonstrated that all possible drift motions, including polarization drift, gradient drift, and curvature drift, which can lead to charge separations, each will attribute to an effective gravity acceleration. Theoretical predictions given by this model are dramatically different from those given by previous theories which have been readily recovered in the theory presented here as a limiting case. The theory shows qualitative agreement with available experimental data of the pitch angle and provides certain predictions to be verified.

Glassy behaviour in simple kinetically constrained models: topological networks, lattice analogues and annihilation-diffusion

NASA Astrophysics Data System (ADS)

Sherrington, David; Davison, Lexie; Buhot, Arnaud; Garrahan, Juan P.

2002-02-01

We report a study of a series of simple model systems with only non-interacting Hamiltonians, and hence simple equilibrium thermodynamics, but with constrained dynamics of a type initially suggested by foams and idealized covalent glasses. We demonstrate that macroscopic dynamical features characteristic of real and more complex model glasses, such as two-time decays in energy and auto-correlation functions, arise from the dynamics and we explain them qualitatively and quantitatively in terms of annihilation-diffusion concepts and theory. The comparison is with strong glasses. We also consider fluctuation-dissipation relations and demonstrate subtleties of interpretation. We find no FDT breakdown when the correct normalization is chosen.

Cochrane Qualitative and Implementation Methods Group guidance series-paper 2: methods for question formulation, searching, and protocol development for qualitative evidence synthesis.

PubMed

Harris, Janet L; Booth, Andrew; Cargo, Margaret; Hannes, Karin; Harden, Angela; Flemming, Kate; Garside, Ruth; Pantoja, Tomas; Thomas, James; Noyes, Jane

2018-05-01

This paper updates previous Cochrane guidance on question formulation, searching, and protocol development, reflecting recent developments in methods for conducting qualitative evidence syntheses to inform Cochrane intervention reviews. Examples are used to illustrate how decisions about boundaries for a review are formed via an iterative process of constructing lines of inquiry and mapping the available information to ascertain whether evidence exists to answer questions related to effectiveness, implementation, feasibility, appropriateness, economic evidence, and equity. The process of question formulation allows reviewers to situate the topic in relation to how it informs and explains effectiveness, using the criterion of meaningfulness, appropriateness, feasibility, and implementation. Questions related to complex questions and interventions can be structured by drawing on an increasingly wide range of question frameworks. Logic models and theoretical frameworks are useful tools for conceptually mapping the literature to illustrate the complexity of the phenomenon of interest. Furthermore, protocol development may require iterative question formulation and searching. Consequently, the final protocol may function as a guide rather than a prescriptive route map, particularly in qualitative reviews that ask more exploratory and open-ended questions. Copyright © 2017 Elsevier Inc. All rights reserved.

The influence of incommensurability on the long-range periodicity of the Pd(100)-(√{ 5 } ×√{ 5 })R27°-PdO(101)

NASA Astrophysics Data System (ADS)

Shipilin, Mikhail; Stierle, Andreas; Merte, Lindsay R.; Gustafson, Johan; Hejral, Uta; Martin, Natalia M.; Zhang, Chu; Franz, Dirk; Kilic, Volkan; Lundgren, Edvin

2017-06-01

The structural model of the (√{ 5 } ×√{ 5 })R27°-PdO(101) surface oxide grown on Pd(100) has been proposed and refined by a number of authors over more than a decade. In the current contribution we discuss the long-range periodicity of this structure arising along one of the crystallographic directions due to its incommensurability with the substrate. Analyzing the results of surface sensitive diffraction studies, we determined a slight distortion of the previously reported perfect (√{ 5 } ×√{ 5 })R27° surface oxide unit cell. Considering it, we were able to achieve both qualitatively and quantitatively better fit to the experimental diffraction data than it was possible for the perfect structure. Further, taking into account the experimentally obtained scanning tunneling microscopy data and closely examining high-resolution patterns recorded by means of high-energy surface X-ray diffraction, we developed a qualitative structural model based on a larger non-orthogonal surface unit cell to shed more light on the long-range order of the PdO(101) surface oxide. The model comprises a shift of the atoms of the PdO perpendicularly to the direction of the incommensurability to correct for it. This structural model reproduces the fine details of the high-resolution diffraction patterns and qualitatively explains the periodic stripes of structural distortion observed in the images recorded by a scanning tunneling microscope.

A Qualitative Case Study Approach To Examine Information Resources Management. (Utilisation d'une Approche Qualitative par Methode de cas pour Etudier la Gestion des Ressources D'information).

ERIC Educational Resources Information Center

Bergeron, Pierrette

1997-01-01

Illustrates how a qualitative approach was used to study the complex and poorly defined concept of information resources management. Explains the general approach to data collection, its advantages and limitations, and the process used to analyze the data. Presents results, along with lessons learned through using method. (Author/AEF)

Comparison of two weighted integration models for the cueing task: linear and likelihood

NASA Technical Reports Server (NTRS)

Shimozaki, Steven S.; Eckstein, Miguel P.; Abbey, Craig K.

2003-01-01

In a task in which the observer must detect a signal at two locations, presenting a precue that predicts the location of a signal leads to improved performance with a valid cue (signal location matches the cue), compared to an invalid cue (signal location does not match the cue). The cue validity effect has often been explained with a limited capacity attentional mechanism improving the perceptual quality at the cued location. Alternatively, the cueing effect can also be explained by unlimited capacity models that assume a weighted combination of noisy responses across the two locations. We compare two weighted integration models, a linear model and a sum of weighted likelihoods model based on a Bayesian observer. While qualitatively these models are similar, quantitatively they predict different cue validity effects as the signal-to-noise ratios (SNR) increase. To test these models, 3 observers performed in a cued discrimination task of Gaussian targets with an 80% valid precue across a broad range of SNR's. Analysis of a limited capacity attentional switching model was also included and rejected. The sum of weighted likelihoods model best described the psychophysical results, suggesting that human observers approximate a weighted combination of likelihoods, and not a weighted linear combination.

Large-scale dynamics and transport in the stratosphere

NASA Technical Reports Server (NTRS)

Plumb, R. A.

1990-01-01

Stationary planetary waves in the southern stratosphere display a characteristic seasonal cycle. Previous research based on a one-dimensional model suggests that this behavior is mainly determined by seasonally varying transmission properties of the atmosphere with respect to wave propagation. The issue is investigated with the help of a hemispheric, linear, quasigeostrophic model. It reproduces well some of the observed qualitative features and is internally consistent in the sense that its seasonal wave cycle can be explained in terms of varying wave transmission properties of the mean circulation. On the other hand, the model does not yield the observed seasonal cycle. Despite considerable sensitivity to modifications in the basic state wind and dissipation parametrization, the model could not be reasonably fit to reproduce the observed seasonal cycle.

Synthesis of line profiles from models of structured winds

NASA Technical Reports Server (NTRS)

Puls, J.; Feldmeier, A.; Springmann, U. W. E.; Owocki, S. P.; Fullerton, A. W.

1994-01-01

On the basis of a careful analysis of resonance line formation (both for singlets and doublets) in structured winds, present time dependent models of the line driven winds of hot stars are shown to be able to explain a number of observational features with respect to variability and structure: they are (in principle) able to reproduce the black and broad troughs (without any artificial 'turbulence velocity') and the 'blue edge variability' observed in saturate resonance lines: they might explain the 'long lived narrow absorption components' often observed in unsaturated lines at high velocities; they predict a relation between the 'edge velocity' of UV-lines and the radiation temperature of the observed X-ray emission. As a first example of the extent to which theoretical models can be constrained by comparisons between observations and profiles calculated by spectrum synthesis from structured winds, we show here that models with deep-seated onset of structure formation (approximately greater than 1.1 R(sub *)) produce resonance lines which agree qualitatively with observational findings; in contrast, the here presented models with structure formation only well out in the wind (approximately greater than 1.6 R(sub *) fail in this respect.

Evidence-Based Identification of Key Beliefs Explaining Infant Male Circumcision Motivation Among Expectant Parents in Zimbabwe: Targets for Behavior Change Messaging.

PubMed

Montaño, Daniel E; Tshimanga, Mufuta; Hamilton, Deven T; Gorn, Gerald; Kasprzyk, Danuta

2018-02-01

Slow adult male circumcision uptake is one factor leading some to recommend increased priority for infant male circumcision (IMC) in sub-Saharan African countries. This research, guided by the integrated behavioral model (IBM), was carried out to identify key beliefs that best explain Zimbabwean parents' motivation to have their infant sons circumcised. A quantitative survey, designed from qualitative elicitation study results, was administered to independent representative samples of 800 expectant mothers and 795 expectant fathers in two urban and two rural areas in Zimbabwe. Multiple regression analyses found IMC motivation among fathers was explained by instrumental attitude, descriptive norm and self-efficacy; while motivation among mothers was explained by instrumental attitude, injunctive norm, descriptive norm, self-efficacy, and perceived control. Regression analyses of beliefs underlying IBM constructs found some overlap but many differences in key beliefs explaining IMC motivation among mothers and fathers. We found differences in key beliefs among urban and rural parents. Urban fathers' IMC motivation was explained best by behavioral beliefs, while rural fathers' motivation was explained by both behavioral and efficacy beliefs. Urban mothers' IMC motivation was explained primarily by behavioral and normative beliefs, while rural mothers' motivation was explained mostly by behavioral beliefs. The key beliefs we identified should serve as targets for developing messages to improve demand and maximize parent uptake as IMC programs are rolled out. These targets need to be different among urban and rural expectant mothers and fathers.

Qualitative Collection Analysis: The Conspectus Methodology. SPEC Kit 151.

ERIC Educational Resources Information Center

Jakubs, Deborah

The introduction to this Systems and Procedures Exchange Center (SPEC) kit explains the Conspectus method, which was developed in 1980 by the Research Libraries Group (RLG) as a means of systematically and qualitatively evaluating large library collections. The discussion considers advantages and disadvantages of this tool, which evaluates past…

A Qualitative Approach to Sketch the Graph of a Function.

ERIC Educational Resources Information Center

Alson, Pedro

1992-01-01

Presents a qualitative and global method of graphing functions that involves transformations of the graph of a known function in the cartesian coordinate system referred to as graphic operators. Explains how the method has been taught to students and some comments about the results obtained. (MDH)

Paradigm Privilege: Determining the Value of Research in Teacher Education Policy Making.

ERIC Educational Resources Information Center

Bales, Barbara L.

This paper explains that despite the long debate over the relative value of quantitative and qualitative educational research and attempts to talk across disciplines, quantitative research dominates educational policy circles. As a result, quality qualitative research may not enter into educational policy conversations. The paper discusses whether…

Pretending to Know: Ethnography, Artistry and Audience

ERIC Educational Resources Information Center

Mienczakowski, Jim

2009-01-01

Qualitative research has moved significantly in the last decade or so in its validation and acceptance of avenues of knowing and explaining which span alternative modes of research dissemination than those more traditionally expected of the academy. The use of performance constructs and conventions in the interpretation of qualitative research has…

Third Grade Elementary Students' Perception of Science

ERIC Educational Resources Information Center

Demir, Metin

2015-01-01

The current study investigated which dimensions of scientific process are capitalized on by elementary school third graders to explain the concept of science at conceptual level. The study was conducted by using "Basic Qualitative Research", one of the qualitative research approaches with the participation of 225 elementary school third…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolejko, Krzysztof; Celerier, Marie-Noeelle; Laboratoire Univers et Theories

We use different particular classes of axially symmetric Szekeres Swiss-cheese models for the study of the apparent dimming of the supernovae of type Ia. We compare the results with those obtained in the corresponding Lemaitre-Tolman Swiss-cheese models. Although the quantitative picture is different the qualitative results are comparable, i.e., one cannot fully explain the dimming of the supernovae using small-scale ({approx}50 Mpc) inhomogeneities. To fit successfully the data we need structures of order of 500 Mpc size or larger. However, this result might be an artifact due to the use of axial light rays in axially symmetric models. Anyhow, thismore » work is a first step in trying to use Szekeres Swiss-cheese models in cosmology and it will be followed by the study of more physical models with still less symmetry.« less

An egalitarian network model for the emergence of simple and complex cells in visual cortex

PubMed Central

Tao, Louis; Shelley, Michael; McLaughlin, David; Shapley, Robert

2004-01-01

We explain how simple and complex cells arise in a large-scale neuronal network model of the primary visual cortex of the macaque. Our model consists of ≈4,000 integrate-and-fire, conductance-based point neurons, representing the cells in a small, 1-mm2 patch of an input layer of the primary visual cortex. In the model the local connections are isotropic and nonspecific, and convergent input from the lateral geniculate nucleus confers cortical cells with orientation and spatial phase preference. The balance between lateral connections and lateral geniculate nucleus drive determines whether individual neurons in this recurrent circuit are simple or complex. The model reproduces qualitatively the experimentally observed distributions of both extracellular and intracellular measures of simple and complex response. PMID:14695891

Young adults' decision making surrounding heavy drinking: a multi-staged model of planned behaviour.

PubMed

Northcote, Jeremy

2011-06-01

This paper examines the real life contexts in which decisions surrounding heavy drinking are made by young adults (that is, on occasions when five or more alcoholic drinks are consumed within a few hours). It presents a conceptual model that views such decision making as a multi-faceted and multi-staged process. The mixed method study draws on purposive data gathered through direct observation of eight social networks consisting of 81 young adults aged between 18 and 25 years in Perth, Western Australia, including in-depth interviews with 31 participants. Qualitative and some basic quantitative data were gathered using participant observation and in-depth interviews undertaken over an eighteen month period. Participants explained their decision to engage in heavy drinking as based on a variety of factors. These elements relate to socio-cultural norms and expectancies that are best explained by the theory of planned behaviour. A framework is proposed that characterises heavy drinking as taking place in a multi-staged manner, with young adults having: 1. A generalised orientation to the value of heavy drinking shaped by wider influences and norms; 2. A short-term orientation shaped by situational factors that determines drinking intentions for specific events; and 3. An evaluative orientation shaped by moderating factors. The value of qualitative studies of decision making in real life contexts is advanced to complement the mostly quantitative research that dominates research on alcohol decision making. Copyright © 2011 Elsevier Ltd. All rights reserved.

Modeling X-ray and gamma-ray emission in the intrabinary shock of pulsar binaries

NASA Astrophysics Data System (ADS)

An, H.

2017-10-01

We present broadband SED and light curve, and a wind interaction model for the gamma-ray binary 1FGL J1018.6-5856 (J1018) which exhibits double peaks in the X-ray light curve. Assuming that the X-ray to low-energy gamma-ray emission is produced by synchrotron radiation and high-energy gamma rays by inverse Compton scattering in the intrabinary shock (IBS), we model the broadband SED and light curve of J1018 using a two-component model having slow electrons in the shock and fast bulk-accelerated electrons at the skin of the shock. The model explains the broadband SED and light curve of J1018 qualitatively well. In particular, modeling the synchrotron emission constrains the orbital geometry. We discuss potential use of the model for other pulsar binaries.

Explaining dark matter and neutrino mass in the light of TYPE-II seesaw model

NASA Astrophysics Data System (ADS)

Biswas, Anirban; Shaw, Avirup

2018-02-01

With the motivation of simultaneously explaining dark matter and neutrino masses, mixing angles, we have invoked the Type-II seesaw model extended by an extra SU(2) doublet Φ. Moreover, we have imposed a Z2 parity on Φ which remains unbroken as the vacuum expectation value of Φ is zero. Consequently, the lightest neutral component of Φ becomes naturally stable and can be a viable dark matter candidate. On the other hand, light Majorana masses for neutrinos have been generated following usual Type-II seesaw mechanism. Further in this framework, for the first time we have derived the full set of vacuum stability and unitarity conditions, which must be satisfied to obtain a stable vacuum as well as to preserve the unitarity of the model respectively. Thereafter, we have performed extensive phenomenological studies of both dark matter and neutrino sectors considering all possible theoretical and current experimental constraints. Finally, we have also discussed a qualitative collider signatures of dark matter and associated odd particles at the 13 TeV Large Hadron Collider.

A model of plasma current through a hole of Rogowski probe including sheath effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furui, H., E-mail: furui@fusion.k.u-tokyo.ac.jp; Ejiri, A.; Takase, Y.

2016-04-15

In TST-2 Ohmic discharges, local current is measured using a Rogowski probe by changing the angle between the local magnetic field and the direction of the hole of the Rogowski probe. The angular dependence shows a peak when the direction of the hole is almost parallel to the local magnetic field. The obtained width of the peak was broader than that of the theoretical curve expected from the probe geometry. In order to explain this disagreement, we consider the effect of sheath in the vicinity of the Rogowski probe. A sheath model was constructed and electron orbits were numerically calculated.more » From the calculation, it was found that the electron orbit is affected by E × B drift due to the sheath electric field. Such orbit causes the broadening of the peak in the angular dependence and the dependence agrees with the experimental results. The dependence of the broadening on various plasma parameters was studied numerically and explained qualitatively by a simplified analytical model.« less

Modeling the acceptance of clinical information systems among hospital medical staff: an extended TAM model.

PubMed

Melas, Christos D; Zampetakis, Leonidas A; Dimopoulou, Anastasia; Moustakis, Vassilis

2011-08-01

Recent empirical research has utilized the Technology Acceptance Model (TAM) to advance the understanding of doctors' and nurses' technology acceptance in the workplace. However, the majority of the reported studies are either qualitative in nature or use small convenience samples of medical staff. Additionally, in very few studies moderators are either used or assessed despite their importance in TAM based research. The present study focuses on the application of TAM in order to explain the intention to use clinical information systems, in a random sample of 604 medical staff (534 physicians) working in 14 hospitals in Greece. We introduce physicians' specialty as a moderator in TAM and test medical staff's information and communication technology (ICT) knowledge and ICT feature demands, as external variables. The results show that TAM predicts a substantial proportion of the intention to use clinical information systems. Findings make a contribution to the literature by replicating, explaining and advancing the TAM, whereas theory is benefited by the addition of external variables and medical specialty as a moderator. Recommendations for further research are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

Fertility Decline in Rural China: A Comparative Analysis

PubMed Central

Harrell, Stevan; Yuesheng, Wang; Hua, Han; Santos, Gonçalo D.; Yingying, Zhou

2014-01-01

Many models have been proposed to explain both the rapidity of China’s fertility decline after the 1960s and the differential timing of the decline in different places. In particular, scholars argue over whether deliberate policies of fertility control, institutional changes, or general modernization factors contribute most to changes in fertility behavior. Here the authors adopt an ethnographically grounded behavioral–institutional approach to analyze qualitative and quantitative data from three different rural settings: Xiaoshan County in Zhejiang (East China), Ci County in Hebei (North China), and Yingde County in Guangdong (South China). The authors show that no one set of factors explains the differential timing and rapidity of the fertility decline in the three areas; rather they must explain differential timing by a combination of differences in social–cultural environments (e.g., spread of education, reproductive ideologies, and gender relations) and politico-economic conditions (e.g., economic development, birth planning campaigns, and collective systems of labor organization) during the early phases of the fertility decline. PMID:21319442

Evidence for and implications of self-healing pulses of slip in earthquake rupture

USGS Publications Warehouse

Heaton, T.H.

1990-01-01

Dislocation time histories of models derived from waveforms of seven earthquakes are discussed. In each model, dislocation rise times (the duration of slip for a given point on the fault) are found to be short compared to the overall duration of the earthquake (??? 10%). However, in many crack-like numerical models of dynamic rupture, the slip duration at a given point is comparable to the overall duration of the rupture; i.e. slip at a given point continues until information is received that the rupture has stopped propagating. Alternative explanations for the discrepancy between the short slip durations used to model waveforms and the long slip durations inferred from dynamic crack models are: (1) the dislocation models are unable to resolve the relatively slow parts of earthquake slip and have seriously underestimated the dislocations for these earthquakes; (2) earthquakes are composed of a sequence of small-dimension (short duration) events that are separated by locked regions (barriers); (3) rupture occurs in a narrow self-healing pulse of slip that travels along the fault surface. Evidence is discussed that suggests that slip durations are indeed short and that the self-healing slip-pulse model is the most appropriate explanation. A qualitative model is presented that produces self-healing slip pulses. The key feature of the model is the assumption that friction on the fault surface is inversely related to the local slip velocity. The model has the following features: high static strength of materials (kilobar range), low static stress drops (in the range of tens of bars), and relatively low frictional stress during slip (less than several hundreds of bars). It is suggested that the reason that the average dislocation scales with fault length is because large-amplitude slip pulses are difficult to stop and hence tend to propagate large distances. This model may explain why seismicity and ambient stress are low along fault segments that have experienced large earthquakes. It also qualitatively explains why the recurrence time for large earthquakes may be irregular. ?? 1990.

Unravelling gossamer with boxing gloves: problems in explaining the decline in smoking.

PubMed Central

Chapman, S

1993-01-01

For about three decades countries such as Australia, Great Britain, and the United States have been turning up the heat on tobacco advertising. Encouraging, sometimes dramatic falls in consumption have followed. On any given day in 1993 smokers in such countries are exposed to a welter of news, information, persuasion, and policies designed to turn them off smoking. For a long time explanations and evaluations of the effects of these policies and interventions have been tied to oversimplified causal models when the reality is rather more messy and complicated. Four factors largely explain the reluctance of researchers to move beyond these models: the reductionist tradition of science; the explanatory privileging of recent events and factors; pragmatic concern for policy "tractable" factors; and the relation of funding to the evaluative process. Broader research approaches to understanding changes in complex behaviours such as smoking are required--for example, qualitative methods. Images p431-a p432-a PMID:8374457

Multi-keV x-ray sources from metal-lined cylindrical hohlraums

NASA Astrophysics Data System (ADS)

Jacquet, L.; Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph.

2012-08-01

As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are ˜6%-8% for titanium, ˜2% for copper, and ˜0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.

Stakeholder experiences with general practice pharmacist services: a qualitative study.

PubMed

Tan, Edwin C K; Stewart, Kay; Elliott, Rohan A; George, Johnson

2013-09-11

To explore general practice staff, pharmacist and patient experiences with pharmacist services in Australian general practice clinics within the Pharmacists in Practice Study. Qualitative study. Two general practice clinics in Melbourne, Australia, in which pharmacists provided medication reviews, patient and staff education, medicines information and quality assurance services over a 6-month period. Patients, practice staff and pharmacists. Semi-structured telephone interviews with patients, focus groups with practice staff and semi-structured interviews and periodic narrative reports with practice pharmacists. Data were analysed thematically and theoretical frameworks used to explain the findings. 34 participants were recruited: 18 patients, 14 practice staff (9 general practitioners, 4 practice nurses, 1 practice manager) and 2 practice pharmacists. Five main themes emerged: environment; professional relationships and integration; pharmacist attributes; staff and patient benefits and logistical challenges. Participants reported that colocation and the interdisciplinary environment of general practice enabled better communication and collaboration compared to traditional community and consultant pharmacy services. Participants felt that pharmacists needed to possess certain attributes to ensure successful integration, including being personable and proactive. Attitudinal, professional and logistical barriers were identified but were able to be overcome. The findings were explained using D'Amour's structuration model of collaboration and Roger's diffusion of innovation theory. This is the first qualitative study to explore the experiences of general practice staff, pharmacists and patients on their interactions within the Australian general practice environment. Participants were receptive of colocated pharmacist services, and various barriers and facilitators to integration were identified. Future research should investigate the feasibility and sustainability of general practice pharmacist roles.

Szekeres Swiss-cheese model and supernova observations

NASA Astrophysics Data System (ADS)

Bolejko, Krzysztof; Célérier, Marie-Noëlle

2010-11-01

We use different particular classes of axially symmetric Szekeres Swiss-cheese models for the study of the apparent dimming of the supernovae of type Ia. We compare the results with those obtained in the corresponding Lemaître-Tolman Swiss-cheese models. Although the quantitative picture is different the qualitative results are comparable, i.e., one cannot fully explain the dimming of the supernovae using small-scale (˜50Mpc) inhomogeneities. To fit successfully the data we need structures of order of 500 Mpc size or larger. However, this result might be an artifact due to the use of axial light rays in axially symmetric models. Anyhow, this work is a first step in trying to use Szekeres Swiss-cheese models in cosmology and it will be followed by the study of more physical models with still less symmetry.

Entropic vs. elastic models of fragility of glass-forming liquids: Two sides of the same coin?

NASA Astrophysics Data System (ADS)

Sen, Sabyasachi

2012-10-01

The two most influential atomistic models that have been proposed in the literature to explain the temperature dependent activation energy of viscous flow of a glass-forming liquid, i.e., its fragility, are the configurational entropy model of Adam and Gibbs [J. Chem. Phys. 43, 139 (1965), 10.1063/1.1696442] and the elastic "shoving" model of Dyre et al. [J. Non-Cryst. Solids 352, 4635 (2006), 10.1016/j.jnoncrysol.2006.02.173]. Here we demonstrate a qualitative equivalence between these two models starting from the well-established general relationships between the interatomic potentials, elastic constants, structural rearrangement, and entropy in amorphous materials. The unification of these two models provides important predictions that are consistent with experimental observations and shed new light into the problem of glass transition.

Electromigration model for the prediction of lifetime based on the failure unit statistics in aluminum metallization

NASA Astrophysics Data System (ADS)

Park, Jong Ho; Ahn, Byung Tae

2003-01-01

A failure model for electromigration based on the "failure unit model" was presented for the prediction of lifetime in metal lines.The failure unit model, which consists of failure units in parallel and series, can predict both the median time to failure (MTTF) and the deviation in the time to failure (DTTF) in Al metal lines. The model can describe them only qualitatively. In our model, both the probability function of the failure unit in single grain segments and polygrain segments are considered instead of in polygrain segments alone. Based on our model, we calculated MTTF, DTTF, and activation energy for different median grain sizes, grain size distributions, linewidths, line lengths, current densities, and temperatures. Comparisons between our results and published experimental data showed good agreements and our model could explain the previously unexplained phenomena. Our advanced failure unit model might be further applied to other electromigration characteristics of metal lines.

How LIS Scholars Conceptualize Rigor in Qualitative Data

ERIC Educational Resources Information Center

Dempsey, Paula R.

2018-01-01

This study investigated how library and information science (LIS) scholars who used qualitative data explained and justified their methods. It analyzed research tasks mentioned in the methods sections of 151 peer-reviewed LIS studies published from 2011 to 2015 and in a survey of their authors. The study assumed that professors of LIS would…

The mathematical bases for qualitative reasoning

NASA Technical Reports Server (NTRS)

Kalagnanam, Jayant; Simon, Herbert A.; Iwasaki, Yumi

1991-01-01

The practices of researchers in many fields who use qualitative reasoning are summarized and explained. The goal is to gain an understanding of the formal assumptions and mechanisms that underlie this kind of analysis. The explanations given are based on standard mathematical formalisms, particularly on ordinal properties, continuous differentiable functions, and the mathematics of nonlinear dynamic systems.

Teaching Electric Circuits with Multiple Batteries: A Qualitative Approach

ERIC Educational Resources Information Center

Smith, David P.; van Kampen, Paul

2011-01-01

We have investigated preservice science teachers' qualitative understanding of circuits consisting of multiple batteries in single and multiple loops using a pretest and post-test method and classroom observations. We found that most students were unable to explain the effects of adding batteries in single and multiple loops, as they tended to use…

Structural equation model of total phosphorus loads in the Red River of the North Basin, USA and Canada

USGS Publications Warehouse

Ryberg, Karen R.

2017-01-01

Attribution of the causes of trends in nutrient loading is often limited to correlation, qualitative reasoning, or references to the work of others. This paper represents efforts to improve causal attribution of water-quality changes. The Red River of the North basin provides a regional test case because of international interest in the reduction of total phosphorus loads and the availability of long-term total phosphorus data and ancillary geospatial data with the potential to explain changes in water quality over time. The objectives of the study are to investigate structural equation modeling methods for application to water-quality problems and to test causal hypotheses related to the drivers of total phosphorus loads over the period 1970 to 2012. Multiple working hypotheses that explain total phosphorus loads and methods for estimating missing ancillary data were developed, and water-quality related challenges to structural equation modeling (including skewed data and scaling issues) were addressed. The model indicates that increased precipitation in season 1 (November–February) or season 2 (March–June) would increase total phosphorus loads in the basin. The effect of agricultural practices on total phosphorus loads was significant, although the effect is about one-third of the effect of season 1 precipitation. The structural equation model representing loads at six sites in the basin shows that climate and agricultural practices explain almost 60% of the annual total phosphorus load in the Red River of the North basin. The modeling process and the unexplained variance highlight the need for better ancillary long-term data for causal assessments.

Successful Inaugural Major Comprehensive Campaigns: How Organizational Learning Theory Helps Explain the Process

ERIC Educational Resources Information Center

Razafimanjato, Laza Johany

2016-01-01

This qualitative study consisted of two case studies of southern public metropolitan universities, which successfully completed inaugural major comprehensive fundraising campaigns. The purpose of the study was to explore how the process of initiating and competing an inaugural comprehensive fundraising campaign was explained by organizational…

Teenagers' Explanations of Bullying

ERIC Educational Resources Information Center

Thornberg, Robert; Knutsen, Sven

2011-01-01

The aim of the present study was to explore how teenagers explain why bullying takes place at school, and whether there were any differences in explaining bullying due to gender and prior bullying experiences. One hundred and seventy-six Swedish students in Grade 9 responded to a questionnaire. Mixed methods (qualitative and quantitative methods)…

The Others: Equitable Access, International Students, and the Community College

ERIC Educational Resources Information Center

Viggiano, Tiffany; López Damián, Ariadna I.; Morales Vázquez, Evelyn; Levin, John S.

2018-01-01

This qualitative investigation explains the ways in which community college decision makers justify the inclusion of international students at three community colleges in the United States. We identify and explain the ways in which decision makers rationalize institutional policy--particularly recruitment strategies and motivations--related to…

Film, Literature, and Education: Trace of Ecopsychology Research in Indonesia

ERIC Educational Resources Information Center

Ahmadi, Anas; Ghazali, Syukur; Dermawan, Taufik; Maryaeni

2017-01-01

In this study, it is explained about the development of ecopsychology in Indonesia. Related to that, the research focus are ecopsychology development and ecopsychology concretization of education in Indonesia. This research uses descriptive-qualitative approach to explain about ecopsychology in Indonesia. Based on the research results, the…

Cycles of self-pulsations in a photonic integrated circuit.

PubMed

Karsaklian Dal Bosco, Andreas; Kanno, Kazutaka; Uchida, Atsushi; Sciamanna, Marc; Harayama, Takahisa; Yoshimura, Kazuyuki

2015-12-01

We report experimentally on the bifurcation cascade leading to the appearance of self-pulsation in a photonic integrated circuit in which a laser diode is subjected to delayed optical feedback. We study the evolution of the self-pulsing frequency with the increase of both the feedback strength and the injection current. Experimental observations show good qualitative accordance with numerical results carried out with the Lang-Kobayashi rate equation model. We explain the mechanism underlying the self-pulsations by a phenomenon of beating between successive pairs of external cavity modes and antimodes.

Bounded rationality leads to equilibrium of public goods games.

PubMed

Xu, Zhaojin; Wang, Zhen; Zhang, Lianzhong

2009-12-01

In this work, we introduce a degree of rationality to the public goods games in which players can determine whether or not to participate, and with it a new mechanism has been established. Existence of the bounded rationality would lead to a new equilibrium which differs from the Nash equilibrium and qualitatively explains the fundamental role of loners' payoff for maintaining cooperation. Meanwhile, it is shown how the potential strategy influences the players' decision. Finally, we explicitly demonstrate a rock-scissors-paper dynamics which is a consequence of this model.

Bounded rationality leads to equilibrium of public goods games

NASA Astrophysics Data System (ADS)

Xu, Zhaojin; Wang, Zhen; Zhang, Lianzhong

2009-12-01

In this work, we introduce a degree of rationality to the public goods games in which players can determine whether or not to participate, and with it a new mechanism has been established. Existence of the bounded rationality would lead to a new equilibrium which differs from the Nash equilibrium and qualitatively explains the fundamental role of loners’ payoff for maintaining cooperation. Meanwhile, it is shown how the potential strategy influences the players’ decision. Finally, we explicitly demonstrate a rock-scissors-paper dynamics which is a consequence of this model.

Extreme energetic particle decreases near geostationary orbit - A manifestation of current diversion within the inner plasma sheet

NASA Technical Reports Server (NTRS)

Baker, D. N.; Mcpherron, R. L.

1990-01-01

A qualitative model of cross-tail current flow is considered. It is suggested that when magnetic reconnection begins, the current effectively flows across the plasma sheet both earthward and tailward of the disruption region near the neutral line. It is shown that an enhanced cross-tail current earthward of this region would thin the plasma sheet substantially due to the magnetic pinch effect. The results explain the very taillike field and extreme particle dropouts often seen late in substorm growth phases.

Meta-ethnography to understand healthcare professionals’ experience of treating adults with chronic non-malignant pain

PubMed Central

Seers, Kate; Barker, Karen L

2017-01-01

Objectives We aimed to explore healthcare professionals’ experience of treating chronic non-malignant pain by conducting a qualitative evidence synthesis. Understanding this experience from the perspective of healthcare professionals will contribute to improvements in the provision of care. Design Qualitative evidence synthesis using meta-ethnography. We searched five electronic bibliographic databases from inception to November 2016. We included studies that explore healthcare professionals’ experience of treating adults with chronic non-malignant pain. We used the GRADE-CERQual framework to rate confidence in review findings. Results We screened the 954 abstracts and 184 full texts and included 77 published studies reporting the experiences of over 1551 international healthcare professionals including doctors, nurses and other health professionals. We abstracted six themes: (1) a sceptical cultural lens, (2) navigating juxtaposed models of medicine, (3) navigating the geography between patient and clinician, (4) challenge of dual advocacy, (5) personal costs and (6) the craft of pain management. We rated confidence in review findings as moderate to high. Conclusions This is the first qualitative evidence synthesis of healthcare professionals’ experiences of treating people with chronic non-malignant pain. We have presented a model that we developed to help healthcare professionals to understand, think about and modify their experiences of treating patients with chronic pain. Our findings highlight scepticism about chronic pain that might explain why patients feel they are not believed. Findings also indicate a dualism in the biopsychosocial model and the complexity of navigating therapeutic relationships. Our model may be transferable to other patient groups or situations. PMID:29273663

[The relevance of qualitative techniques in biomedical research].

PubMed

de Camargo, Kenneth Rochel

2008-01-01

On observing how qualitative and quantitative studies are reported in the biomedical literature it becomes evident that, besides the virtual absence of the former, they are presented in different ways. Authors of qualitative studies seem to need almost invariably to explain why they choose a qualitative approach whereas that does not occur in quantitative studies. This paper takes Ludwik Fleck's comparative epistemology as a means of exploring those differences empirically, illustrating on the basis of two studies dealing with different aspects of biomedical practices how qualitative methods can elucidate a variety of questions pertaining to this field. The paper concludes presenting some structural characteristics of the biomedical field which on one hand, would not be explored properly without employing qualitative methods and, on the other hand, can help understanding the little value given to qualitative techniques in this area.

Students' mental models on the solubility and solubility product concept

NASA Astrophysics Data System (ADS)

Rahmi, Chusnur; Katmiati, Siti; Wiji, Mulyani, Sri

2017-05-01

This study aims to obtain some information regarding profile of students' mental models on the solubility and solubility product concept. A descriptive qualitative method was the method employed in the study. The participants of the study were students XI grade of a senior high school in Bandung. To collect the data, diagnostic test on mental model-prediction, observation, explanation (TDM-POE) instrument was employed in the study. The results of the study revealed that on the concept of precipitation formation of a reaction, 30% of students were not able to explain the precipitation formation of a reaction either in submicroscopic or symbolic level although the microscopic have been shown; 26% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, but they were not able to explain the interaction of particles that involved in the reaction and to calculate Qsp; 26% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, and determine the particles involved, but they did not have the knowledge about the interactions occured and were uncapable of calculating Qsp; and 18% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, and determine the interactions of the particles involved in the reactions but they were not able to calculate Qsp. On the effect of adding common ions and decreasing pH towards the solubility concept, 96% of students were not able to explain the effect of adding common ions and decreasing pH towards the solubility either in submicroscopic or symbolic level although the microscopic have been shown; while 4% of students were only able to explain the effect of adding common ions towards the solubility based on the chemical equilibrium shifts and predict the effect of decreasing pH towards the solubility. However, they were not able to calculate the solubility before and after adding common ions and explain it up to the submicroscopic level either based on the shift of equilibrium solubility or the comparison of solubility calculation results before and after decreasing pH. Overall, the present study showed that most students obtain incomplete mental model on the solubility and solubility product concept. From the findings, it is recommended for the teachers to improve students' learning activity.

Computational modeling of mediator oxidation by oxygen in an amperometric glucose biosensor.

PubMed

Simelevičius, Dainius; Petrauskas, Karolis; Baronas, Romas; Razumienė, Julija

2014-02-07

In this paper, an amperometric glucose biosensor is modeled numerically. The model is based on non-stationary reaction-diffusion type equations. The model consists of four layers. An enzyme layer lies directly on a working electrode surface. The enzyme layer is attached to an electrode by a polyvinyl alcohol (PVA) coated terylene membrane. This membrane is modeled as a PVA layer and a terylene layer, which have different diffusivities. The fourth layer of the model is the diffusion layer, which is modeled using the Nernst approach. The system of partial differential equations is solved numerically using the finite difference technique. The operation of the biosensor was analyzed computationally with special emphasis on the biosensor response sensitivity to oxygen when the experiment was carried out in aerobic conditions. Particularly, numerical experiments show that the overall biosensor response sensitivity to oxygen is insignificant. The simulation results qualitatively explain and confirm the experimentally observed biosensor behavior.

Computational Modeling of Mediator Oxidation by Oxygen in an Amperometric Glucose Biosensor

PubMed Central

Šimelevičius, Dainius; Petrauskas, Karolis; Baronas, Romas; Julija, Razumienė

2014-01-01

In this paper, an amperometric glucose biosensor is modeled numerically. The model is based on non-stationary reaction-diffusion type equations. The model consists of four layers. An enzyme layer lies directly on a working electrode surface. The enzyme layer is attached to an electrode by a polyvinyl alcohol (PVA) coated terylene membrane. This membrane is modeled as a PVA layer and a terylene layer, which have different diffusivities. The fourth layer of the model is the diffusion layer, which is modeled using the Nernst approach. The system of partial differential equations is solved numerically using the finite difference technique. The operation of the biosensor was analyzed computationally with special emphasis on the biosensor response sensitivity to oxygen when the experiment was carried out in aerobic conditions. Particularly, numerical experiments show that the overall biosensor response sensitivity to oxygen is insignificant. The simulation results qualitatively explain and confirm the experimentally observed biosensor behavior. PMID:24514882

On the simple random-walk models of ion-channel gate dynamics reflecting long-term memory.

PubMed

Wawrzkiewicz, Agata; Pawelek, Krzysztof; Borys, Przemyslaw; Dworakowska, Beata; Grzywna, Zbigniew J

2012-06-01

Several approaches to ion-channel gating modelling have been proposed. Although many models describe the dwell-time distributions correctly, they are incapable of predicting and explaining the long-term correlations between the lengths of adjacent openings and closings of a channel. In this paper we propose two simple random-walk models of the gating dynamics of voltage and Ca(2+)-activated potassium channels which qualitatively reproduce the dwell-time distributions, and describe the experimentally observed long-term memory quite well. Biological interpretation of both models is presented. In particular, the origin of the correlations is associated with fluctuations of channel mass density. The long-term memory effect, as measured by Hurst R/S analysis of experimental single-channel patch-clamp recordings, is close to the behaviour predicted by our models. The flexibility of the models enables their use as templates for other types of ion channel.

Elements affecting food waste in the food service sector.

PubMed

Heikkilä, Lotta; Reinikainen, Anu; Katajajuuri, Juha-Matti; Silvennoinen, Kirsi; Hartikainen, Hanna

2016-10-01

Avoidable food waste is produced in the food service sector, with significant ecological and economical impacts. In order to understand and explain better the complex issue of food waste a qualitative study was conducted on the reasons for its generation in restaurants and catering businesses. Research data were collected during three participatory workshops for personnel from three different catering sector companies in Finland. Based on synthesized qualitative content analysis, eight elements influencing production and reduction of food waste were identified. Results revealed the diversity of managing food waste in the food service sector and how a holistic approach is required to prevent and reduce it. It is crucial to understand that food waste is manageable and should be an integral component of the management system. The model of eight factors provides a framework for recognition and management of food waste in the food service sector. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of the Bernoulli enthalpy concept to the study of vortex noise and jet impingement noise

NASA Technical Reports Server (NTRS)

Yates, J. E.

1978-01-01

A complete theory of aeroacoustics of homentropic fluid media is developed and compared with previous theories. The theory is applied to study the interaction of sound with vortex flows, for the DC-9 in a standard take-off configuration. The maximum engine-wake interference noise is estimated to be 3 or 4 db in the ground plane. It is shown that the noise produced by a corotating vortex pair departs significantly from the compact M scaling law for eddy Mach numbers (M) greater than 0.1. An estimate of jet impingement noise is given that is in qualitative agreement with experimental results. The increased noise results primarily from the nonuniform acceleration of turbulent eddies through the stagnation point flow. It is shown that the corotating vortex pair can be excited or de-excited by an externally applied sound field. The model is used to qualitatively explain experimental results on excited jets.

Variables affecting learning in a simulation experience: a mixed methods study.

PubMed

Beischel, Kelly P

2013-02-01

The primary purpose of this study was to test a hypothesized model describing the direct effects of learning variables on anxiety and cognitive learning outcomes in a high-fidelity simulation (HFS) experience. The secondary purpose was to explain and explore student perceptions concerning the qualities and context of HFS affecting anxiety and learning. This study used a mixed methods quantitative-dominant explanatory design with concurrent qualitative data collection to examine variables affecting learning in undergraduate, beginning nursing students (N = 124). Being ready to learn, having a strong auditory-verbal learning style, and being prepared for simulation directly affected anxiety, whereas learning outcomes were directly affected by having strong auditory-verbal and hands-on learning styles. Anxiety did not quantitatively mediate cognitive learning outcomes as theorized, although students qualitatively reported debilitating levels of anxiety. This study advances nursing education science by providing evidence concerning variables affecting learning outcomes in HFS.

Junior High School Physics: Using a Qualitative Strategy for Successful Problem Solving

ERIC Educational Resources Information Center

Mualem, Roni; Eylon, Bat Sheva

2010-01-01

Students at the junior high school (JHS) level often cannot use their knowledge of physics for explaining and predicting phenomena. We claim that this difficulty stems from the fact that explanations are multi-step reasoning tasks, and students often lack the qualitative problem-solving strategies needed to guide them. This article describes a new…

Symbolic Interactionism and Library Research: Using a Qualitative Methodology To Understand Library Interchange.

ERIC Educational Resources Information Center

Fidishun, Dolores

2002-01-01

Explains symbolic interactionism as a theory for analyzing research based on a qualitative interpretive process that can help librarians to understand the way in which the library staff and users view services, training, policy, and other issues. The theory focuses on the symbolic meaning of objects, such as books, and events as they are…

School Transitions: A Qualitative Study of the Supports Provided by Washington State Special Education Administrators

ERIC Educational Resources Information Center

Lewinsohn, Kari

2013-01-01

This study investigated the role of special education administrators in the transition planning process for children with disabilities ages 3-21 in selected Washington school districts. A basic qualitative study was selected to construct meaning from a described phenomenon. The study sought to identify and explain how special education…

Raman scattering of Cisplatin near silver nanoparticles

NASA Astrophysics Data System (ADS)

Mirsaleh-Kohan, Nasrin; Duplanty, Michael; Torres, Marjorie; Moazzezi, Mojtaba; Rostovtsev, Yuri V.

2018-03-01

The Raman scattering of Cisplatin (the first generation of anticancer drugs) has been studied. In the presence of silver nanoparticles, strong modifications of Raman spectra have been observed. The Raman frequencies have been shifted and the line profiles are broadened. We develop a theoretical model to explain the observed features of the Raman scattering. The model takes into account self-consistently the interaction of molecules with surface plasmonic waves excited in the silver nanoparticles, and it provides a qualitative agreement with the observed Raman spectra. We have demonstrated that the using silver nanoparticles can increase sensitivity of the technique, and potentially it has a broader range of applications to both spectroscopy and microscopy.

A Simple Model for Immature Retrovirus Capsid Assembly

NASA Astrophysics Data System (ADS)

Paquay, Stefan; van der Schoot, Paul; Dragnea, Bogdan

In this talk I will present simulations of a simple model for capsomeres in immature virus capsids, consisting of only point particles with a tunable range of attraction constrained to a spherical surface. We find that, at sufficiently low density, a short interaction range is sufficient for the suppression of five-fold defects in the packing and causes instead larger tears and scars in the capsid. These findings agree both qualitatively and quantitatively with experiments on immature retrovirus capsids, implying that the structure of the retroviral protein lattice can, for a large part, be explained simply by the effective interaction between the capsomeres. We thank the HFSP for funding under Grant RGP0017/2012.

Engine Data Interpretation System (EDIS)

NASA Technical Reports Server (NTRS)

Cost, Thomas L.; Hofmann, Martin O.

1990-01-01

A prototype of an expert system was developed which applies qualitative or model-based reasoning to the task of post-test analysis and diagnosis of data resulting from a rocket engine firing. A combined component-based and process theory approach is adopted as the basis for system modeling. Such an approach provides a framework for explaining both normal and deviant system behavior in terms of individual component functionality. The diagnosis function is applied to digitized sensor time-histories generated during engine firings. The generic system is applicable to any liquid rocket engine but was adapted specifically in this work to the Space Shuttle Main Engine (SSME). The system is applied to idealized data resulting from turbomachinery malfunction in the SSME.

Explaining Self-Harm: Youth Cybertalk and Marginalized Sexualities and Genders

ERIC Educational Resources Information Center

McDermott, Elizabeth; Roen, Katrina; Piela, Anna

2015-01-01

This study investigates self-harm among young lesbian, gay, bisexual, and trans (LGBT) people. Using qualitative virtual methods, we examined online forums to explore young LGBT people's cybertalk about emotional distress and self-harming. We investigated how youth explained the relationship between self-harm and sexuality and gender. We found…

Contradictions between and within School and University Activity Systems Helping to Explain Students' Difficulty with Advanced Mathematics

ERIC Educational Resources Information Center

Jooganah, Kamila; Williams, Julian S.

2016-01-01

This article explores how contradictions, as framed by activity theory (Engeström, 1987), can explain first-year undergraduate students' experiences of learning advanced mathematics. Analysing qualitative interview and observational data of students and lecturers based in one university mathematics department, we argue that contradictions between…

Ahead of the Pack? Explaining the Unequal Distribution of Scholarships in Germany

ERIC Educational Resources Information Center

Haas, Christina; Van De Werfhorst, Herman

2017-01-01

This article investigates to what extent scholarships are unequally distributed among students in Germany and how these inequalities can be explained. Following sociological theory, the article argues that elites seek qualitative ways of distinguishing themselves in a mass higher education system. Using student surveys, we demonstrate that class…

Testing a cognitive model to predict posttraumatic stress disorder following childbirth.

PubMed

King, Lydia; McKenzie-McHarg, Kirstie; Horsch, Antje

2017-01-14

One third of women describes their childbirth as traumatic and between 0.8 and 6.9% goes on to develop posttraumatic stress disorder (PTSD). The cognitive model of PTSD has been shown to be applicable to a range of trauma samples. However, childbirth is qualitatively different to other trauma types and special consideration needs to be taken when applying it to this population. Previous studies have investigated some cognitive variables in isolation but no study has so far looked at all the key processes described in the cognitive model. This study therefore aimed to investigate whether theoretically-derived variables of the cognitive model explain unique variance in postnatal PTSD symptoms when key demographic, obstetric and clinical risk factors are controlled for. One-hundred and fifty-seven women who were between 1 and 12 months post-partum (M = 6.5 months) completed validated questionnaires assessing PTSD and depressive symptoms, childbirth experience, postnatal social support, trauma memory, peritraumatic processing, negative appraisals, dysfunctional cognitive and behavioural strategies and obstetric as well as demographic risk factors in an online survey. A PTSD screening questionnaire suggested that 5.7% of the sample might fulfil diagnostic criteria for PTSD. Overall, risk factors alone predicted 43% of variance in PTSD symptoms and cognitive behavioural factors alone predicted 72.7%. A final model including both risk factors and cognitive behavioural factors explained 73.7% of the variance in PTSD symptoms, 37.1% of which was unique variance predicted by cognitive factors. All variables derived from Ehlers and Clark's cognitive model significantly explained variance in PTSD symptoms following childbirth, even when clinical, demographic and obstetric were controlled for. Our findings suggest that the CBT model is applicable and useful as a way of understanding and informing the treatment of PTSD following childbirth.

Effect of extracurricular geriatric medicine training: a model based on student reflections on healthcare delivery to elderly people.

PubMed

Goldenhar, Linda M; Margolin, E Gordon; Warshaw, Gregg

2008-03-01

Although many professional and accrediting bodies have identified competencies for medical students pertaining to caring for older patients, including understanding the basics of the healthcare delivery system, the highly structured curriculum in medical school provides few opportunities for these competencies to be achieved. One possible solution is to let students participate in geriatrics-related extracurricular educational and clinical activities and ask them to reflect on their experiences. This article presents the results of a qualitative analysis of student reflections from participating in such a program implemented at the University of Cincinnati College of Medicine. One hundred thirty of 321 student journal entries (collected over 3 academic years) containing any mention of the healthcare system were qualitatively analyzed. The themes and resulting model that emerged from the data includes three distinct levels of healthcare delivery: individual, organizational, and systems. Each level is presented and explained using illustrative student quotes. As a whole, the model indicates that students in this innovative extracurricular experience gained important knowledge about how medical care is provided to elderly people. The model developed may provide additional structure for future medical students as they reflect on their early encounters with the complex health and social forces affecting the quality of care received by older adults.

Modeling the factors affecting unsafe behavior in the construction industry from safety supervisors' perspective.

PubMed

Khosravi, Yahya; Asilian-Mahabadi, Hassan; Hajizadeh, Ebrahim; Hassanzadeh-Rangi, Narmin; Bastani, Hamid; Khavanin, Ali; Mortazavi, Seyed Bagher

2014-01-01

There can be little doubt that the construction is the most hazardous industry in the worldwide. This study was designed to modeling the factors affecting unsafe behavior from the perspective of safety supervisors. The qualitative research was conducted to extract a conceptual model. A structural model was then developed based on a questionnaire survey (n=266) by two stage Structural Equation Model (SEM) approach. An excellent confirmed 12-factors structure explained about 62% of variances unsafe behavior in the construction industry. A good fit structural model indicated that safety climate factors were positively correlated with safety individual factors (P<0.001) and workplace safety condition (P<0.001). The workplace safety condition was found to play a strong mediating role in linking the safety climate and construction workers' engagement in safe or unsafe behavior. In order to improve construction safety performance, more focus on the workplace condition is required.

Theory and interpretation in qualitative studies from general practice: Why and how?

PubMed

Malterud, Kirsti

2016-03-01

In this article, I want to promote theoretical awareness and commitment among qualitative researchers in general practice and suggest adequate and feasible theoretical approaches. I discuss different theoretical aspects of qualitative research and present the basic foundations of the interpretative paradigm. Associations between paradigms, philosophies, methodologies and methods are examined and different strategies for theoretical commitment presented. Finally, I discuss the impact of theory for interpretation and the development of general practice knowledge. A scientific theory is a consistent and soundly based set of assumptions about a specific aspect of the world, predicting or explaining a phenomenon. Qualitative research is situated in an interpretative paradigm where notions about particular human experiences in context are recognized from different subject positions. Basic theoretical features from the philosophy of science explain why and how this is different from positivism. Reflexivity, including theoretical awareness and consistency, demonstrates interpretative assumptions, accounting for situated knowledge. Different types of theoretical commitment in qualitative analysis are presented, emphasizing substantive theories to sharpen the interpretative focus. Such approaches are clearly within reach for a general practice researcher contributing to clinical practice by doing more than summarizing what the participants talked about, without trying to become a philosopher. Qualitative studies from general practice deserve stronger theoretical awareness and commitment than what is currently established. Persistent attention to and respect for the distinctive domain of knowledge and practice where the research deliveries are targeted is necessary to choose adequate theoretical endeavours. © 2015 the Nordic Societies of Public Health.

Using the framework method for the analysis of qualitative data in multi-disciplinary health research.

PubMed

Gale, Nicola K; Heath, Gemma; Cameron, Elaine; Rashid, Sabina; Redwood, Sabi

2013-09-18

The Framework Method is becoming an increasingly popular approach to the management and analysis of qualitative data in health research. However, there is confusion about its potential application and limitations. The article discusses when it is appropriate to adopt the Framework Method and explains the procedure for using it in multi-disciplinary health research teams, or those that involve clinicians, patients and lay people. The stages of the method are illustrated using examples from a published study. Used effectively, with the leadership of an experienced qualitative researcher, the Framework Method is a systematic and flexible approach to analysing qualitative data and is appropriate for use in research teams even where not all members have previous experience of conducting qualitative research.

Discrete-Slots Models of Visual Working-Memory Response Times

PubMed Central

Donkin, Christopher; Nosofsky, Robert M.; Gold, Jason M.; Shiffrin, Richard M.

2014-01-01

Much recent research has aimed to establish whether visual working memory (WM) is better characterized by a limited number of discrete all-or-none slots or by a continuous sharing of memory resources. To date, however, researchers have not considered the response-time (RT) predictions of discrete-slots versus shared-resources models. To complement the past research in this field, we formalize a family of mixed-state, discrete-slots models for explaining choice and RTs in tasks of visual WM change detection. In the tasks under investigation, a small set of visual items is presented, followed by a test item in 1 of the studied positions for which a change judgment must be made. According to the models, if the studied item in that position is retained in 1 of the discrete slots, then a memory-based evidence-accumulation process determines the choice and the RT; if the studied item in that position is missing, then a guessing-based accumulation process operates. Observed RT distributions are therefore theorized to arise as probabilistic mixtures of the memory-based and guessing distributions. We formalize an analogous set of continuous shared-resources models. The model classes are tested on individual subjects with both qualitative contrasts and quantitative fits to RT-distribution data. The discrete-slots models provide much better qualitative and quantitative accounts of the RT and choice data than do the shared-resources models, although there is some evidence for “slots plus resources” when memory set size is very small. PMID:24015956

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: A new mammalian circadian oscillator model including the cAMP module

NASA Astrophysics Data System (ADS)

Wang, Jun-Wei; Zhou, Tian-Shou

2009-12-01

In this paper, we develop a new mathematical model for the mammalian circadian clock, which incorporates both transcriptional/translational feedback loops (TTFLs) and a cAMP-mediated feedback loop. The model shows that TTFLs and cAMP signalling cooperatively drive the circadian rhythms. It reproduces typical experimental observations with qualitative similarities, e.g. circadian oscillations in constant darkness and entrainment to light-dark cycles. In addition, it can explain the phenotypes of cAMP-mutant and Rev-erbα-/--mutant mice, and help us make an experimentally-testable prediction: oscillations may be rescued when arrhythmic mice with constitutively low concentrations of cAMP are crossed with Rev-erbα-/- mutant mice. The model enhances our understanding of the mammalian circadian clockwork from the viewpoint of the entire cell.

"What about People Our Age?" Applying Qualitative and Quantitative Methods to Uncover How Political Ads Alienate College Students

ERIC Educational Resources Information Center

Parmelee, John H.; Perkins, Stephynie C.; Sayre, Judith J.

2007-01-01

This study uses a sequential transformative mixed methods research design to explain how political advertising fails to engage college students. Qualitative focus groups examined how college students interpret the value of political advertising to them, and a quantitative manifest content analysis concerning ad framing of more than 100 ads from…

The Study of Electronic Medical Record Adoption in a Medicare Certified Home Health Agency Using a Grounded Theory Approach

ERIC Educational Resources Information Center

May, Joy L.

2013-01-01

The purpose of this qualitative grounded theory study was to examine the experiences of clinicians in the adoption of Electronic Medical Records in a Medicare certified Home Health Agency. An additional goal for this study was to triangulate qualitative research between describing, explaining, and exploring technology acceptance. The experiences…

Understanding the physical attractiveness literature: Qualitative reviews versus meta-analysis.

PubMed

Feingold, Alan

2017-01-01

The target article is a qualitative review of selected findings in the physical attractiveness literature. This commentary explains why the meta-analytic approach, frequently used by other attractiveness reviewers, is preferable for drawing unbiased conclusions about the effects of attractiveness. The article's main contribution is affording a foundation for subsequent meta-analysis of the studies discussed in a subjective fashion.

A study of the electric field in an open magnetospheric model

NASA Technical Reports Server (NTRS)

Stern, D. P.

1973-01-01

Recently, Svalgaard and Heppner reported two separate features of the polar electromagnetic field that correlate with the dawn-dusk component of the interplanetary magnetic field. This work attempts to explain these findings in terms of properties of the open magnetosphere. The topology and qualitative properties of the open magnetosphere are first studied by means of a simple model, consisting of a dipole in a constant field. Many such properties are found to depend on the separation line, a curve connecting neutral points and separating different field line regimes. In the simple model it turns out that the electric field in the central polar cap tends to point from dawn to dusk for a wide variety of external fields, but, near the boundary of the polar cap, electric equipotentials are deformed into crescents.

A nutrient dependant switch explains mutually exclusive existence of meiosis and mitosis initiation in budding yeast.

PubMed

Wannige, C T; Kulasiri, D; Samarasinghe, S

2014-01-21

Nutrients from living environment are vital for the survival and growth of any organism. Budding yeast diploid cells decide to grow by mitosis type cell division or decide to create unique, stress resistant spores by meiosis type cell division depending on the available nutrient conditions. To gain a molecular systems level understanding of the nutrient dependant switching between meiosis and mitosis initiation in diploid cells of budding yeast, we develop a theoretical model based on ordinary differential equations (ODEs) including the mitosis initiator and its relations to budding yeast meiosis initiation network. Our model accurately and qualitatively predicts the experimentally revealed temporal variations of related proteins under different nutrient conditions as well as the diverse mutant studies related to meiosis and mitosis initiation. Using this model, we show how the meiosis and mitosis initiators form an all-or-none type bistable switch in response to available nutrient level (mainly nitrogen). The transitions to and from meiosis or mitosis initiation states occur via saddle node bifurcation. This bidirectional switch helps the optimal usage of available nutrients and explains the mutually exclusive existence of meiosis and mitosis pathways. © 2013 Elsevier Ltd. All rights reserved.

Reactivity and reactions to regulatory transparency in medicine, psychotherapy and counselling.

PubMed

McGivern, Gerry; Fischer, Michael D

2012-02-01

We explore how doctors, psychotherapists and counsellors in the U.K. react to regulatory transparency, drawing on qualitative research involving 51 semi-structured interviews conducted during 2008-10. We use the concept of 'reactivity mechanisms' (Espeland & Sauder, 2007) to explain how regulatory transparency disrupts practices through simplifying and decontextualizing them, altering practitioners' reflexivity, leading to defensive forms of practice. We make an empirical contribution by exploring the impact of transparency on doctors compared with psychotherapists and counsellors, who represent an extreme case due to their uniquely complex practice, which is particularly affected by this form of regulation. We make a contribution to knowledge by developing a model of reactivity mechanisms, which explains how clinical professionals make sense of media and professional narratives about regulation in ways that produce emotional reactions and, in turn, defensive reactivity to transparency. Copyright © 2011 Elsevier Ltd. All rights reserved.

Variation of high-power aluminum-wire array Z-pinch dynamics with wire number, load mass, and array radius

NASA Astrophysics Data System (ADS)

Sanford, T. W. L.; Mock, R. C.; Marder, B. M.; Nash, T. J.; Spielman, R. B.; Peterson, D. L.; Roderick, N. F.; Hammer, J. H.; De Groot, J. S.; Mosher, D.; Whitney, K. G.; Apruzese, J. P.

1997-05-01

A systematic study of annular aluminum-wire z-pinches on the Saturn accelerator shows that the quality of the implosion, (as measured by the radial convergence, the radiated energy, pulse width, and power), increases with wire number. Radiation magnetohydrodynamic (RMHC) xy simulations suggest that the implosion transitions from that of individual wire plasmas to that of a continuous plasma shell when the interwire spacing is reduced below ˜1.4 mm. In this "plasma-shell regime," many of the global radiation and plasma characteristics are in agreement with those simulated by 2D-RMHC rz simulations. In this regime, measured changes in the radiation pulse width with variations in load mass and array radius are consistent with the simulations and are explained by the development of 2D fluid motion in the rz plane. Associated variations in the K-shell yield are qualitatively explained by simple radiation-scaling models.

A mixture of sparse coding models explaining properties of face neurons related to holistic and parts-based processing

PubMed Central

2017-01-01

Experimental studies have revealed evidence of both parts-based and holistic representations of objects and faces in the primate visual system. However, it is still a mystery how such seemingly contradictory types of processing can coexist within a single system. Here, we propose a novel theory called mixture of sparse coding models, inspired by the formation of category-specific subregions in the inferotemporal (IT) cortex. We developed a hierarchical network that constructed a mixture of two sparse coding submodels on top of a simple Gabor analysis. The submodels were each trained with face or non-face object images, which resulted in separate representations of facial parts and object parts. Importantly, evoked neural activities were modeled by Bayesian inference, which had a top-down explaining-away effect that enabled recognition of an individual part to depend strongly on the category of the whole input. We show that this explaining-away effect was indeed crucial for the units in the face submodel to exhibit significant selectivity to face images over object images in a similar way to actual face-selective neurons in the macaque IT cortex. Furthermore, the model explained, qualitatively and quantitatively, several tuning properties to facial features found in the middle patch of face processing in IT as documented by Freiwald, Tsao, and Livingstone (2009). These included, in particular, tuning to only a small number of facial features that were often related to geometrically large parts like face outline and hair, preference and anti-preference of extreme facial features (e.g., very large/small inter-eye distance), and reduction of the gain of feature tuning for partial face stimuli compared to whole face stimuli. Thus, we hypothesize that the coding principle of facial features in the middle patch of face processing in the macaque IT cortex may be closely related to mixture of sparse coding models. PMID:28742816

A mixture of sparse coding models explaining properties of face neurons related to holistic and parts-based processing.

PubMed

Hosoya, Haruo; Hyvärinen, Aapo

2017-07-01

Experimental studies have revealed evidence of both parts-based and holistic representations of objects and faces in the primate visual system. However, it is still a mystery how such seemingly contradictory types of processing can coexist within a single system. Here, we propose a novel theory called mixture of sparse coding models, inspired by the formation of category-specific subregions in the inferotemporal (IT) cortex. We developed a hierarchical network that constructed a mixture of two sparse coding submodels on top of a simple Gabor analysis. The submodels were each trained with face or non-face object images, which resulted in separate representations of facial parts and object parts. Importantly, evoked neural activities were modeled by Bayesian inference, which had a top-down explaining-away effect that enabled recognition of an individual part to depend strongly on the category of the whole input. We show that this explaining-away effect was indeed crucial for the units in the face submodel to exhibit significant selectivity to face images over object images in a similar way to actual face-selective neurons in the macaque IT cortex. Furthermore, the model explained, qualitatively and quantitatively, several tuning properties to facial features found in the middle patch of face processing in IT as documented by Freiwald, Tsao, and Livingstone (2009). These included, in particular, tuning to only a small number of facial features that were often related to geometrically large parts like face outline and hair, preference and anti-preference of extreme facial features (e.g., very large/small inter-eye distance), and reduction of the gain of feature tuning for partial face stimuli compared to whole face stimuli. Thus, we hypothesize that the coding principle of facial features in the middle patch of face processing in the macaque IT cortex may be closely related to mixture of sparse coding models.

A heuristic mathematical model for the dynamics of sensory conflict and motion sickness

NASA Technical Reports Server (NTRS)

Oman, C. M.

1982-01-01

The etiology of motion sickness is now usually explained in terms of a qualitatively formulated sensory conflict hypothesis. By consideration of the information processing task faced by the central nervous system in estimating body spatial orientation and in controlling active body movement using an internal model referenced control strategy, a mathematical model for sensory conflict generation is developed. The model postulates a major dynamic functional role for sensory conflict signals in movement control, as well as in sensory motor adaptation. It accounts for the role of active movement in creating motion sickness symptoms in some experimental circumstances, and in alleviating them in others. The relationship between motion sickness produced by sensory rearrangement and that resulting from external motion disturbances is explicitly defined. A nonlinear conflict averaging model describes dynamic aspects of experimentally observed subjective discomfort sensation, and suggests resulting behavior.

A heuristic mathematical model for the dynamics of sensory conflict and motion sickness

NASA Technical Reports Server (NTRS)

Oman, C. M.

1980-01-01

The etiology of motion sickness is explained in terms of a qualitatively formulated sensory conflict hypothesis. By consideration of the information processing task faced by the central nervous system in estimating body spatial orientation and in controlling active body movement using an internal model referenced control strategy, a mathematical model for sensory conflict generation is developed. The model postulates a major dynamic functional role for sensory conflict signals in movement control, as well as in sensory-motor adaptation. It accounts for the role of active movement in creating motion sickness symptoms in some experimental circumstances, and in alleviating them in others. The relationship between motion sickness produced by sensory rearrangement and that resulting from external motion disturbances is explicitly defined. A nonlinear conflict averaging model is proposed which describes dynamic aspects of experimentally observed subjective discomfort sensation, and suggests resulting behaviors.

The consentaneous model of the financial markets exhibiting spurious nature of long-range memory

NASA Astrophysics Data System (ADS)

Gontis, V.; Kononovicius, A.

2018-09-01

It is widely accepted that there is strong persistence in the volatility of financial time series. The origin of the observed persistence, or long-range memory, is still an open problem as the observed phenomenon could be a spurious effect. Earlier we have proposed the consentaneous model of the financial markets based on the non-linear stochastic differential equations. The consentaneous model successfully reproduces empirical probability and power spectral densities of volatility. This approach is qualitatively different from models built using fractional Brownian motion. In this contribution we investigate burst and inter-burst duration statistics of volatility in the financial markets employing the consentaneous model. Our analysis provides an evidence that empirical statistical properties of burst and inter-burst duration can be explained by non-linear stochastic differential equations driving the volatility in the financial markets. This serves as an strong argument that long-range memory in finance can have spurious nature.

Cortico-hippocampal representations in simultaneous odor discrimination: a computational interpretation of Eichenbaum, Mathews, and Cohen (1989).

PubMed

Myers, C E; Gluck, M A

1996-08-01

A previous model of hippocampal region function in classical conditioning is generalized to H. Eichenbaum, A. Fagan, P. Mathews, and N.J. Cohen's (1989) and H. Eichenbaum, A. Fagan, and N.J. Cohen's (1989) simultaneous odor discrimination studies in rats. The model assumes that the hippocampal region forms new stimulus representations that compress redundant information while differentiating predictie information; the piriform (olfactory) cortex meanwhile clusters similar and co-occurring odors. Hippocampal damage interrupts the ability to differentiate odor representations, while leaving piriform-mediated odor clustering unchecked. The result is a net tendency to overcompress in the lesioned model. Behavior in the model is very similar to that of the rats, including lesion deficits, facilitation of successively learned tasks, and transfer performance. The computational mechanisms underlying model performance are consistent with the qualitative interpretations suggested by Eichen baum et al. to explain their empirical data.

Cognitive Correlates of Inadequate Response to Reading Intervention

PubMed Central

Fletcher, Jack M.; Stuebing, Karla K.; Barth, Amy E.; Denton, Carolyn A.; Cirino, Paul T.; Francis, David J.; Vaughn, Sharon

2012-01-01

The cognitive attributes of Grade 1 students who responded adequately and inadequately to a Tier 2 reading intervention were evaluated. The groups included inadequate responders based on decoding and fluency criteria (n = 29), only fluency criteria (n = 75), adequate responders (n = 85), and typically achieving students (n = 69). The cognitive measures included assessments of phonological awareness, rapid letter naming, oral language skills, processing speed, vocabulary, and nonverbal problem solving. Comparisons of all four groups identified phonological awareness as the most significant contributor to group differentiation. Measures of rapid letter naming, syntactic comprehension/working memory, and vocabulary also contributed uniquely to some comparisons of adequate and inadequate responders. In a series of regression analyses designed to evaluate the contributions of responder status to cognitive skills independently of variability in reading skills, only the model for rapid letter naming achieved statistical significance, accounting for a small (1%) increment in explained variance beyond that explained by models based only on reading levels. Altogether, these results do not suggest qualitative differences among the groups, but are consistent with a continuum of severity associated with the level of reading skills across the four groups. PMID:23125475

Characterization of the IMF By-dependent field-aligned currents in the cleft region based on DE 2 observations

NASA Technical Reports Server (NTRS)

Taguchi, S.; Sugiura, M.; Winningham, J. D.; Slavin, J. A.

1993-01-01

The magnetic field and plasma data from 47 passes of DE-2 are used to study the IMF By-dependent distribution of field-aligned currents in the cleft region. It is proposed that the low-latitude cleft current (LCC) region is not an extension of the region 1 or region 2 current system and that a pair of LCCs and high-latitude cleft currents (HCCs) constitutes the cleft field-aligned current regime. The proposed pair of cleft field-aligned currents is explained with a qualitative model in which this pair of currents is generated on open field lines that have just been reconnected on the dayside magnetopause. The electric fields are transmitted along the field lines to the ionosphere, creating a poleward electric field and a pair of field-aligned currents when By is positive; the pair of field-aligned currents consists of a downward current at lower latitudes and an upward current at higher latitudes. In the By negative case, the model explains the reversal of the field-aligned current direction in the LCC and HCC regions.

Zero-bias offsets in I-V characteristics of the staircase type quantum well infrared photodetectors

NASA Astrophysics Data System (ADS)

Nutku, Ferhat; Erol, Ayse; Arikan, M. Cetin; Ergun, Yuksel

2014-11-01

In this work, observed zero-bias offsets in I-V characteristics and differences in J-V characteristics of staircase quantum well infrared photodetectors were investigated. Temperature and voltage sweep rate dependence of the zero-bias offsets were studied on mesa structures shaped in different diameters. Furthermore, effect of mesa diameter on J-V characteristics was investigated. The temperature, initial bias voltage and voltage sweep rate dependence of the zero-bias offsets were explained by a qualitative model, which is based on a RC equivalent circuit of the quantum well infrared photodetector.

Noise-induced transitions in a double-well oscillator with nonlinear dissipation.

PubMed

Semenov, Vladimir V; Neiman, Alexander B; Vadivasova, Tatyana E; Anishchenko, Vadim S

2016-05-01

We develop a model of bistable oscillator with nonlinear dissipation. Using a numerical simulation and an electronic circuit realization of this system we study its response to additive noise excitations. We show that depending on noise intensity the system undergoes multiple qualitative changes in the structure of its steady-state probability density function (PDF). In particular, the PDF exhibits two pitchfork bifurcations versus noise intensity, which we describe using an effective potential and corresponding normal form of the bifurcation. These stochastic effects are explained by the partition of the phase space by the nullclines of the deterministic oscillator.

Emotional consciousness: a neural model of how cognitive appraisal and somatic perception interact to produce qualitative experience.

PubMed

Thagard, Paul; Aubie, Brandon

2008-09-01

This paper proposes a theory of how conscious emotional experience is produced by the brain as the result of many interacting brain areas coordinated in working memory. These brain areas integrate perceptions of bodily states of an organism with cognitive appraisals of its current situation. Emotions are neural processes that represent the overall cognitive and somatic state of the organism. Conscious experience arises when neural representations achieve high activation as part of working memory. This theory explains numerous phenomena concerning emotional consciousness, including differentiation, integration, intensity, valence, and change.

Mixis and Diagnôsis: Aristotle and the "Chemistry" of the Sublunary World.

PubMed

Viano, Cristina

2015-08-01

In On Generation and Corruption 1.10, Aristotle introduces the new idea of "chemical mixture" (mixis) to explain the constitution of those homogeneous substances from which all things in the sublunary world are comprised. In a mixture, the ingredients interact with one another to give rise to a new substance, qualitatively different, yet preserving the original ingredients in potentia, so that they can be separated again. In Book IV of the Meteorologica, Aristotle further suggests that bodies may be "diagnosed" according to certain passive properties, such as the fusibility of metals. While his theory of mixture has often led historians of science to identify Aristotle as one of the precursors of chemical science, his ideas have also been criticised as archaic, and implicated in a qualitative conception of the cosmos that delayed progress towards quantifying natural phenomena. In this paper, I take up the defence of Aristotle's theory by showing that his concept of mixture is not an obstacle to the development of natural science and chemistry, but, on the contrary, opens the way by offering an advanced model of qualitative analysis which does not exclude the possibility of quantitative development.

Religious leaders' opinions and guidance towards oral health maintenance and promotion: a qualitative study.

PubMed

Zini, Avraham; Sgan-Cohen, Harold D; Feder-Bubis, Paula

2015-04-01

Religions emphasize the supreme value of life. However, potential or concrete conflicts of perception between dictates of faith and science often present an inescapable dilemma. The aim of this qualitative research was to examine the views of spiritual and religious leaders towards general and oral health issues. A total of 11 eminent Jewish spiritual and religious community leaders were purposively chosen. They were interviewed using a semi-structured questionnaire. The verbatim transcriptions of the interviews were analysed in the spirit of grounded theory, using qualitative data analysis software. Open, axial, and thematic coding served to build categories and themes. Analysis of participants' perspectives reflected that they, based upon Jewish theology, attributed high importance to primary prevention at both personal and community levels. Religious and orthodox people were depicted as being motivated towards maintaining oral health behaviours due to a sense of obligation to follow religious edicts, strong social support, and elevated perceived spiritual levels. We offer a theoretical model that can explain the potential high motivation among these communities towards implementing positive general and oral health behaviours. Religiosity may be regarded as an example of a psycho-social health determinant, encompassing spiritual belief ("psycho") and social support ("social") components.

Optimizing clinical and organizational practice in cancer survivor transitions between specialized oncology and primary care teams: a realist evaluation of multiple case studies.

PubMed

Tremblay, Dominique; Prady, Catherine; Bilodeau, Karine; Touati, Nassera; Chouinard, Maud-Christine; Fortin, Martin; Gaboury, Isabelle; Rodrigue, Jean; L'Italien, Marie-France

2017-12-16

Cancer is now viewed as a chronic disease, presenting challenges to follow-up and survivorship care. Models to shift from haphazard, suboptimal and fragmented episodes of care to an integrated cancer care continuum must be developed, tested and implemented. Numerous studies demonstrate improved care when follow-up is assured by both oncology and primary care providers rather than either group alone. However, there is little data on the roles assumed by specialized oncology teams and primary care providers and the extent to which they work together. This study aims to develop, pilot test and measure outcomes of an innovative risk-based coordinated cancer care model for patients transitioning from specialized oncology teams to primary care providers. This multiple case study using a sequential mixed-methods design rests on a theory-driven realist evaluation approach to understand how transitions might be improved. The cases are two health regions in Quebec, Canada, defined by their geographic territory. Each case includes a Cancer Centre and three Family Medicine Groups selected based on differences in their determining characteristics. Qualitative data will be collected from document review (scientific journal, grey literature, local documentation), semi-directed interviews with key informants, and observation of care coordination practices. Qualitative data will be supplemented with a survey to measure the outcome of the coordinated model among providers (scope of practice, collaboration, relational coordination, leadership) and patients diagnosed with breast, colorectal or prostate cancer (access to care, patient-centredness, communication, self-care, survivorship profile, quality of life). Results from descriptive and regression analyses will be triangulated with thematic analysis of qualitative data. Qualitative, quantitative, and mixed methods data will be interpreted within and across cases in order to identify context-mechanism associations that explain outcomes. The study will provide empirical data on a risk-based coordinated model of cancer care to guide actions at different levels in the health system. This in-depth multiple case study using a realist approach considers both the need for context-specific intervention research and the imperative to address research gaps regarding coordinated models of cancer care.

Inter-species investigation of the mechano-regulation of bone healing: comparison of secondary bone healing in sheep and rat.

PubMed

Checa, Sara; Prendergast, Patrick J; Duda, Georg N

2011-04-29

Inter-species differences in regeneration exist in various levels. One aspect is the dynamics of bone regeneration and healing, e.g. small animals show a faster healing response when compared to large animals. Mechanical as well as biological factors are known to play a key role in the process. However, it remains so far unknown whether different animals follow at all comparable mechano-biological rules during tissue regeneration, and in particular during bone healing. In this study, we investigated whether differences observed in vivo in the dynamics of bone healing between rat and sheep are only due to differences in the animal size or whether these animals have a different mechano-biological response during the healing process. Histological sections from in vivo experiments were compared to in silico predictions of a mechano-biological computer model for the simulation of bone healing. Investigations showed that the healing processes in both animal models occur under significantly different levels of mechanical stimuli within the callus region, which could explain histological observations of early intramembranous ossification at the endosteal side. A species-specific adaptation of a mechano-biological model allowed a qualitative match of model predictions with histological observations. Specifically, when keeping cell activity processes at the same rate, the amount of tissue straining defining favorable mechanical conditions for the formation of bone had to be increased in the large animal model, with respect to the small animal, to achieve a qualitative agreement of model predictions with histological data. These findings illustrate that geometrical (size) differences alone cannot explain the distinctions seen in the histological appearance of secondary bone healing in sheep and rat. It can be stated that significant differences in the mechano-biological regulation of the healing process exist between these species. Future investigations should aim towards understanding whether these differences are due to differences in cell behavior, material properties of the newly formed tissues within the callus and/or differences in response to the mechanical environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

System monitoring and diagnosis with qualitative models

NASA Technical Reports Server (NTRS)

Kuipers, Benjamin

1991-01-01

A substantial foundation of tools for model-based reasoning with incomplete knowledge was developed: QSIM (a qualitative simulation program) and its extensions for qualitative simulation; Q2, Q3 and their successors for quantitative reasoning on a qualitative framework; and the CC (component-connection) and QPC (Qualitative Process Theory) model compilers for building QSIM QDE (qualitative differential equation) models starting from different ontological assumptions. Other model-compilers for QDE's, e.g., using bond graphs or compartmental models, have been developed elsewhere. These model-building tools will support automatic construction of qualitative models from physical specifications, and further research into selection of appropriate modeling viewpoints. For monitoring and diagnosis, plausible hypotheses are unified against observations to strengthen or refute the predicted behaviors. In MIMIC (Model Integration via Mesh Interpolation Coefficients), multiple hypothesized models of the system are tracked in parallel in order to reduce the 'missing model' problem. Each model begins as a qualitative model, and is unified with a priori quantitative knowledge and with the stream of incoming observational data. When the model/data unification yields a contradiction, the model is refuted. When there is no contradiction, the predictions of the model are progressively strengthened, for use in procedure planning and differential diagnosis. Only under a qualitative level of description can a finite set of models guarantee the complete coverage necessary for this performance. The results of this research are presented in several publications. Abstracts of these published papers are presented along with abtracts of papers representing work that was synergistic with the NASA grant but funded otherwise. These 28 papers include but are not limited to: 'Combined qualitative and numerical simulation with Q3'; 'Comparative analysis and qualitative integral representations'; 'Model-based monitoring of dynamic systems'; 'Numerical behavior envelopes for qualitative models'; 'Higher-order derivative constraints in qualitative simulation'; and 'Non-intersection of trajectories in qualitative phase space: a global constraint for qualitative simulation.'

[Regulations of sickness certification as a factor for increased health care utilization in Germany].

PubMed

Herrmann, Wolfram J; Haarmann, Alexander; Bærheim, Anders

2015-01-01

In Germany, utilization of ambulatory health care is high compared to other countries. Classical models of health care utilization cannot sufficiently explain these differences. The aim of this study was to explore relevant factors which can explain the higher health care utilization in Germany. In this article, we focus on regulations regarding sickness certification as a potential factor. An explorative qualitative study design. We conducted episodic interviews with 20 patients in Germany and 20 patients in Norway and participant observation in four primary care practices each. Additionally, we conducted a context analysis of relevant health care system related factors which emerged during the study. Qualitative data analysis was done by thematic coding in the framework of grounded theory. The need for a sickness certificate was an important reason for encounter in Germany, especially regarding minor illnesses. Sickness certification is a societal topic. GPs play a double role regarding sickness certification, both as the patients' advocate and as an expert witness for social security services. In Norway, longer periods of self-administered sickness certification and more differentiated possibilities of sickness certification have been introduced successfully. Our results point to regulations regarding sickness certification as a relevant factor for higher health care utilization in Germany. In pilot studies, the effect of extended self-certification of sickness and part-time sickness certification should be further assessed. Copyright © 2015. Published by Elsevier GmbH.

Genetic and Environmental Influences on Smoking Behavior across Adolescence and Young Adulthood in the Virginia Twin Study of Adolescent Behavioral Development and the Transitions to Substance Abuse Follow-Up

PubMed Central

Do, Elizabeth K.; Prom-Wormley, Elizabeth C.; Eaves, Lindon J.; Silberg, Judy L.; Miles, Donna R.; Maes, Hermine H.

2016-01-01

Little is known regarding the underlying relationship between smoking initiation and current quantity smoked during adolescence into young adulthood. It is possible that the influences of genetic and environmental factors on this relationship vary across sex and age. To investigate this further, the current study applied a common causal contingency model to data from a Virginia-based twin study to determine: (1) if the same genetic and environmental factors are contributing to smoking initiation and current quantity smoked; (2) whether the magnitude of genetic and environmental factor contributions are the same across adolescence and young adulthood; and (3) if qualitative and quantitative differences in the sources of variance between males and females exist. Study results found no qualitative or quantitative sex differences in the relationship between smoking initiation and current quantity smoked, though relative contributions of genetic and environmental factors changed across adolescence and young adulthood. More specifically, smoking initiation and current quantity smoked remain separate constructs until young adulthood, when liabilities are correlated. Smoking initiation is explained by genetic, shared, and unique environmental factors in early adolescence and by genetic and unique environmental factors in young adulthood; while current quantity smoked is explained by shared environmental and unique environmental factors until young adulthood, when genetic and unique environmental factors play a larger role. PMID:25662421

Genetic and Environmental Influences on Smoking Behavior across Adolescence and Young Adulthood in the Virginia Twin Study of Adolescent Behavioral Development and the Transitions to Substance Abuse Follow-Up.

PubMed

Do, Elizabeth K; Prom-Wormley, Elizabeth C; Eaves, Lindon J; Silberg, Judy L; Miles, Donna R; Maes, Hermine H

2015-02-01

Little is known regarding the underlying relationship between smoking initiation and current quantity smoked during adolescence into young adulthood. It is possible that the influences of genetic and environmental factors on this relationship vary across sex and age. To investigate this further, the current study applied a common causal contingency model to data from a Virginia-based twin study to determine: (1) if the same genetic and environmental factors are contributing to smoking initiation and current quantity smoked; (2) whether the magnitude of genetic and environmental factor contributions are the same across adolescence and young adulthood; and (3) if qualitative and quantitative differences in the sources of variance between males and females exist. Study results found no qualitative or quantitative sex differences in the relationship between smoking initiation and current quantity smoked, though relative contributions of genetic and environmental factors changed across adolescence and young adulthood. More specifically, smoking initiation and current quantity smoked remain separate constructs until young adulthood, when liabilities are correlated. Smoking initiation is explained by genetic, shared, and unique environmental factors in early adolescence and by genetic and unique environmental factors in young adulthood; while current quantity smoked is explained by shared environmental and unique environmental factors until young adulthood, when genetic and unique environmental factors play a larger role.

Airburst-Generated Tsunamis

NASA Astrophysics Data System (ADS)

Berger, Marsha; Goodman, Jonathan

2018-04-01

This paper examines the questions of whether smaller asteroids that burst in the air over water can generate tsunamis that could pose a threat to distant locations. Such airburst-generated tsunamis are qualitatively different than the more frequently studied earthquake-generated tsunamis, and differ as well from tsunamis generated by asteroids that strike the ocean. Numerical simulations are presented using the shallow water equations in several settings, demonstrating very little tsunami threat from this scenario. A model problem with an explicit solution that demonstrates and explains the same phenomena found in the computations is analyzed. We discuss the question of whether compressibility and dispersion are important effects that should be included, and show results from a more sophisticated model problem using the linearized Euler equations that begins to addresses this.

Understanding the complex interplay of barriers to physical activity amongst black and minority ethnic groups in the United Kingdom: a qualitative synthesis using meta-ethnography.

PubMed

Koshoedo, Sejlo A; Paul-Ebhohimhen, Virginia A; Jepson, Ruth G; Watson, Margaret C

2015-07-12

To conduct a meta-ethnographic analysis of qualitative studies to identify barriers to Black and Minority Ethnic (BME) individuals engaging in physical activity in the UK context. A qualitative synthesis using meta-ethnographic methods to synthesis studies of barriers to engaging in physical activity among BME groups in the UK. A comprehensive search strategy of multiple databases was employed to identify qualitative research studies published up to October 2012. The eleven searched databases included ASSIA, MEDLINE, EMBASE, CINAHL, Health Technology Assessment (HTA), NHS Scotland Library, Physical Activity Health Alliance (PAHA), PsyINFO, Social Services Abstract, Sport discuss and Web of Science. The Noblit and Hare's meta-ethnographic approach was undertaken to develop an inductive and interpretive form of knowledge synthesis. Fourteen papers met the inclusion criteria. The synthesis indicated that barriers to physical activity among BME individuals were influenced by four main concepts: perceptions; cultural expectations; personal barriers; and factors limiting access to facilities. BME individuals had different understandings of physical activity were influenced by migration history, experiences, cultural and health beliefs. This in turn may have a disempowering effect on BME individuals in terms of adopting or maintaining physical activity. These barriers to physical activity were explained at a higher conceptual level by a socio-ecological model. The social construct 'individual perception and understanding of physical activity' was particularly relevant to theoretical models and interventions. Interventions to promote engagement with physical activity need to address perceptions of this behaviour. The elicited concepts and contexts could be used to enhance the development of tailored effective health promotion interventions for BME individuals.

How do Turkish High School Graduates Use the Wave Theory of Light to Explain Optics Phenomena?

ERIC Educational Resources Information Center

Sengoren, S. K.

2010-01-01

This research was intended to investigate whether Turkish students who had graduated from high school used the wave theory of light properly in explaining optical phenomena. The survey method was used in this research. The data, which were collected from 175 first year university students in Turkey, were analysed quantitatively and qualitatively.…

Analysing How Scientists Explain Their Research: A Rubric for Measuring the Effectiveness of Scientific Explanations

ERIC Educational Resources Information Center

Sevian, Hannah; Gonsalves, Lisa

2008-01-01

The present article presents a rubric we developed for assessing the quality of scientific explanations by science graduate students. The rubric was developed from a qualitative analysis of science graduate students' abilities to explain their own research to an audience of non-scientists. Our intention is that use of the rubric to characterise…

Factors Facilitating the Implementation of Church-Based Heart Health Promotion Programs for Older Adults: A Qualitative Study Guided by the Precede-Proceed Model.

PubMed

Banerjee, Ananya Tina; Kin, R; Strachan, Patricia H; Boyle, Michael H; Anand, Sonia S; Oremus, Mark

2015-01-01

To describe the factors facilitating the implementation of heart health promotion programs for older adults in Anglican, United, and Catholic churches. The study used qualitative methods comprising semistructured interviews and focus groups. The interviews and focus groups were conducted in Anglican, Catholic, and United churches located in the Canadian cities of Toronto and Hamilton, Ontario. Twelve ordained pastors and 21 older parishioners who attended church regularly and who had no health conditions were recruited to best explain how churches could be suitable locations for health promotion activities targeting older adults. Twelve semistructured interviews with the pastors and three focus groups with the 21 parishioners were undertaken. A component of the Precede-Proceed model (a model for planning health education and health promotion programs and policies) was applied to the findings after direct content analysis of the data. Participants identified pastor leadership, funding for a parish nurse, community-focused interventions, secured infrastructure, and social support from congregation members as pertinent factors required for implementing health promotion programs in Anglican, United, and Catholic churches. The findings have particular relevance for health promotion and public health because they suggest factors that would be necessary to design church-based heart health promotion programs for older adults at risk of chronic diseases.

Bifurcation analysis and phase diagram of a spin-string model with buckled states.

PubMed

Ruiz-Garcia, M; Bonilla, L L; Prados, A

2017-12-01

We analyze a one-dimensional spin-string model, in which string oscillators are linearly coupled to their two nearest neighbors and to Ising spins representing internal degrees of freedom. String-spin coupling induces a long-range ferromagnetic interaction among spins that competes with a spin-spin antiferromagnetic coupling. As a consequence, the complex phase diagram of the system exhibits different flat rippled and buckled states, with first or second order transition lines between states. This complexity translates to the two-dimensional version of the model, whose numerical solution has been recently used to explain qualitatively the rippled to buckled transition observed in scanning tunneling microscopy experiments with suspended graphene sheets. Here we describe in detail the phase diagram of the simpler one-dimensional model and phase stability using bifurcation theory. This gives additional insight into the physical mechanisms underlying the different phases and the behavior observed in experiments.

A Short-Term Population Model of the Suicide Risk: The Case of Spain.

PubMed

De la Poza, Elena; Jódar, Lucas

2018-06-14

A relevant proportion of deaths by suicide have been attributed to other causes that produce the number of suicides remains hidden. The existence of a hidden number of cases is explained by the nature of the problem. Problems like this involve violence, and produce fear and social shame in victims' families. The existence of violence, fear and social shame experienced by victims favours a considerable number of suicides, identified as accidents or natural deaths. This paper proposes a short time discrete compartmental mathematical model to measure the suicidal risk for the case of Spain. The compartment model classifies and quantifies the amount of the Spanish population within the age intervals (16, 78) by their degree of suicide risk and their changes over time. Intercompartmental transits are due to the combination of quantitative and qualitative factors. Results are computed and simulations are performed to analyze the sensitivity of the model under uncertain coefficients.

A simple polymeric model describes cell nuclear mechanical response

NASA Astrophysics Data System (ADS)

Banigan, Edward; Stephens, Andrew; Marko, John

The cell nucleus must continually resist inter- and intracellular mechanical forces, and proper mechanical response is essential to basic cell biological functions as diverse as migration, differentiation, and gene regulation. Experiments probing nuclear mechanics reveal that the nucleus stiffens under strain, leading to two characteristic regimes of force response. This behavior depends sensitively on the intermediate filament protein lamin A, which comprises the outer layer of the nucleus, and the properties of the chromatin interior. To understand these mechanics, we study a simulation model of a polymeric shell encapsulating a semiflexible polymer. This minimalistic model qualitatively captures the typical experimental nuclear force-extension relation and observed nuclear morphologies. Using a Flory-like theory, we explain the simulation results and mathematically estimate the force-extension relation. The model and experiments suggest that chromatin organization is a dominant contributor to nuclear mechanics, while the lamina protects cell nuclei from large deformations.

Differences between the insulating limit quasiparticles of one-band and three-band cuprate models

NASA Astrophysics Data System (ADS)

Ebrahimnejad, H.; Sawatzky, G. A.; Berciu, M.

2016-03-01

We study the charge dynamics of the quasiparticle that forms when a single hole is doped in a two-dimensional antiferromagnet as described by the one-band t-{{t}\\prime} -{{t}\\prime \\prime} -J model, using a variational approximation that includes spin fluctuations in the vicinity of the hole. We explain why the spin fluctuations and the longer range hopping have complementary contributions to the quasiparticle dynamics, and thus why both are essential to obtain a dispersion in agreement with that measured experimentally. This is very different from the three-band Emery model in the strongly-correlated limit, where the same variational approximation shows that spin fluctuations have a minor effect on the quasiparticle dynamics. This difference proves that these one-band and three-band models describe qualitatively different quasiparticles in the insulating limit, and therefore that they cannot both be suitable to describe the physics of very underdoped cuprates.

Vibration transmission through rolling element bearings in geared rotor system, part 1. Ph.D. Thesis Final Report

NASA Technical Reports Server (NTRS)

Singh, Rajendra; Lim, Teik Chin

1989-01-01

A mathematical model is proposed to examine the vibration transmission through rolling element bearings in geared rotor systems. Current bearing models, based on either ideal boundary conditions for the shaft or purely translational stiffness element description, cannot explain how the vibratory motion may be transmitted from the rotating shaft to the casing. This study clarifies this issue qualitatively and quantitatively by developing a comprehensive bearing stiffness matrix of dimension 6 model for the precision rolling element bearings from basic principles. The proposed bearing formulation is extended to analyze the overall geared rotor system dynamics including casing and mounts. The bearing stiffness matrix is included in discrete system models using lumped parameter and/or dynamic finite element techniques. Eigensolution and forced harmonic response due to rotating mass unbalance or kinematic transmission error excitation for a number of examples are computed.

Bifurcation analysis and phase diagram of a spin-string model with buckled states

NASA Astrophysics Data System (ADS)

Ruiz-Garcia, M.; Bonilla, L. L.; Prados, A.

2017-12-01

We analyze a one-dimensional spin-string model, in which string oscillators are linearly coupled to their two nearest neighbors and to Ising spins representing internal degrees of freedom. String-spin coupling induces a long-range ferromagnetic interaction among spins that competes with a spin-spin antiferromagnetic coupling. As a consequence, the complex phase diagram of the system exhibits different flat rippled and buckled states, with first or second order transition lines between states. This complexity translates to the two-dimensional version of the model, whose numerical solution has been recently used to explain qualitatively the rippled to buckled transition observed in scanning tunneling microscopy experiments with suspended graphene sheets. Here we describe in detail the phase diagram of the simpler one-dimensional model and phase stability using bifurcation theory. This gives additional insight into the physical mechanisms underlying the different phases and the behavior observed in experiments.

Modeling fast and slow earthquakes at various scales

PubMed Central

IDE, Satoshi

2014-01-01

Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes. PMID:25311138

Modeling fast and slow earthquakes at various scales.

PubMed

Ide, Satoshi

2014-01-01

Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes.

A model of impulsive acceleration and transport of energetic particles in Mercury's magnetosphere

NASA Technical Reports Server (NTRS)

Baker, D. N.; Simpson, J. A.; Eraker, J. H.

1986-01-01

A qualitative model of substorm processes in the Mercury magnetosphere is presented based on Mariner 10 observations obtained in 1974-1975. The model is predicated on close analogies observed with the terrestrial case. Particular emphasis is given to energetic particle phenomena as observed by Mariner on March 29, 1974. The suggestion is supported that energetic particles up to about 500 keV are produced by strong induced electric fields at 3 to about 6 Mercury radii in the Hermean tail in association with substorm neutral line formation. The bursts of energetic particles produced are, in this model, subsequently confined on closed field lines near Mercury and drift adiabatically on quasi-trapped orbits for many tens of seconds. Such gradient and curvature drift of the particles can explain prominent periodicities of 5-10 s seen in the Mariner for greater than 170-keV electron flux profiles.

Discrepancies between UN models and DHS survey estimates of maternal orphan prevalence: insights from analyses of survey data from Zimbabwe

PubMed Central

Robertson, L; Gregson, S; Madanhire, C; Walker, N; Mushati, P; Garnett, G; Nyamukapa, C

2008-01-01

Objectives: Model-based estimates of maternal (but not paternal) orphanhood are higher than those based on data from demographic and health surveys (DHS). We investigate the consistency of reporting of parental survival status in data from Manicaland, Zimbabwe. Methods: We compared estimates of paternal and maternal orphan prevalence in three rounds of a prospective household census in Manicaland (1998–2005) with estimates from DHS surveys and UNAIDS model projections. We investigated the consistency of reporting of parental survival status across the three rounds and compared estimates of adult mortality from the orphan data with direct estimates from concurrent follow-up of a general population cohort. Qualitative data were collected on possible reasons for misreporting. Results: Paternal and maternal orphan prevalence is increasing in Zimbabwe. Mothers reported as deceased in round 1 of the Manicaland survey were more likely than fathers to be reported as alive in rounds 2 or 3 (33.3% vs 13.4%). This pattern was most apparent among younger children. The qualitative findings suggest that foster parents sometimes claim adopted children as their natural children. Conclusions: These results are consistent with misreporting of foster parents as natural parents. This appears to be particularly common among foster mothers and could partly explain the discrepancy between mathematical model and DHS estimates of maternal orphanhood. PMID:18647868

Nonlinearity of the forward-backward correlation function in the model with string fusion

NASA Astrophysics Data System (ADS)

Vechernin, Vladimir

2017-12-01

The behavior of the forward-backward correlation functions and the corresponding correlation coefficients between multiplicities and transverse momenta of particles produced in high energy hadronic interactions is analyzed by analytical and MC calculations in the models with and without string fusion. The string fusion is taking into account in simplified form by introducing the lattice in the transverse plane. The results obtained with two alternative definitions of the forward-backward correlation coefficient are compared. It is shown that the nonlinearity of correlation functions increases with the width of observation windows, leading at small string density to a strong dependence of correlation coefficient value on the definition. The results of the modeling enable qualitatively to explain the experimentally observed features in the behavior of the correlation functions between multiplicities and mean transverse momenta at small and large multiplicities.

Bootstrapping in a language of thought: a formal model of numerical concept learning.

PubMed

Piantadosi, Steven T; Tenenbaum, Joshua B; Goodman, Noah D

2012-05-01

In acquiring number words, children exhibit a qualitative leap in which they transition from understanding a few number words, to possessing a rich system of interrelated numerical concepts. We present a computational framework for understanding this inductive leap as the consequence of statistical inference over a sufficiently powerful representational system. We provide an implemented model that is powerful enough to learn number word meanings and other related conceptual systems from naturalistic data. The model shows that bootstrapping can be made computationally and philosophically well-founded as a theory of number learning. Our approach demonstrates how learners may combine core cognitive operations to build sophisticated representations during the course of development, and how this process explains observed developmental patterns in number word learning. Copyright © 2011 Elsevier B.V. All rights reserved.

A pharmacokinetic model of filgrastim and pegfilgrastim application in normal mice and those with cyclophosphamide-induced granulocytopaenia.

PubMed

Scholz, M; Ackermann, M; Engel, C; Emmrich, F; Loeffler, M; Kamprad, M

2009-12-01

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is widely used as treatment for granulocytopaenia during cytotoxic chemotherapy; however, optimal scheduling of this pharmaceutical is unknown. Biomathematical models can help to pre-select optimal application schedules but precise pharmacokinetic properties of the pharmaceuticals are required at first. In this study, we have aimed to construct a pharmacokinetic model of G-CSF derivatives filgrastim and pegfilgrastim in mice. Healthy CD-1 mice and those with cyclophosphamide-induced granulocytopaenia were studied after administration of filgrastim and pegfilgrastim in different dosing and timing schedules. Close meshed time series of granulocytes and G-CSF plasma concentrations were determined. An ordinary differential equations model of pharmacokinetics was constructed on the basis of known mechanisms of drug distribution and degradation. Predictions of the model fit well with all experimental data for both filgrastim and pegfilgrastim. We obtained a unique parameter setting for all experimental scenarios. Differences in pharmacokinetics between filgrastim and pegfilgrastim can be explained by different estimates of model parameters rather than by different model mechanisms. Parameter estimates with respect to distribution and clearance of the drug derivatives are in agreement with qualitative experimental results. Dynamics of filgrastim and pegfilgrastim plasma levels can be explained by the same pharmacokinetic model but different model parameters. Beause of a strong clearance mechanism mediated by granulocytes, granulocytotic and granulocytopaenic conditions must be studied simultaneously to construct a reliable model. The pharmacokinetic model will be extended to a murine model of granulopoiesis under chemotherapy and G-CSF application.

How to do a grounded theory study: a worked example of a study of dental practices

PubMed Central

2011-01-01

Background Qualitative methodologies are increasingly popular in medical research. Grounded theory is the methodology most-often cited by authors of qualitative studies in medicine, but it has been suggested that many 'grounded theory' studies are not concordant with the methodology. In this paper we provide a worked example of a grounded theory project. Our aim is to provide a model for practice, to connect medical researchers with a useful methodology, and to increase the quality of 'grounded theory' research published in the medical literature. Methods We documented a worked example of using grounded theory methodology in practice. Results We describe our sampling, data collection, data analysis and interpretation. We explain how these steps were consistent with grounded theory methodology, and show how they related to one another. Grounded theory methodology assisted us to develop a detailed model of the process of adapting preventive protocols into dental practice, and to analyse variation in this process in different dental practices. Conclusions By employing grounded theory methodology rigorously, medical researchers can better design and justify their methods, and produce high-quality findings that will be more useful to patients, professionals and the research community. PMID:21902844

How to do a grounded theory study: a worked example of a study of dental practices.

PubMed

Sbaraini, Alexandra; Carter, Stacy M; Evans, R Wendell; Blinkhorn, Anthony

2011-09-09

Qualitative methodologies are increasingly popular in medical research. Grounded theory is the methodology most-often cited by authors of qualitative studies in medicine, but it has been suggested that many 'grounded theory' studies are not concordant with the methodology. In this paper we provide a worked example of a grounded theory project. Our aim is to provide a model for practice, to connect medical researchers with a useful methodology, and to increase the quality of 'grounded theory' research published in the medical literature. We documented a worked example of using grounded theory methodology in practice. We describe our sampling, data collection, data analysis and interpretation. We explain how these steps were consistent with grounded theory methodology, and show how they related to one another. Grounded theory methodology assisted us to develop a detailed model of the process of adapting preventive protocols into dental practice, and to analyse variation in this process in different dental practices. By employing grounded theory methodology rigorously, medical researchers can better design and justify their methods, and produce high-quality findings that will be more useful to patients, professionals and the research community.

Emergence of Lévy walks in systems of interacting individuals

NASA Astrophysics Data System (ADS)

Fedotov, Sergei; Korabel, Nickolay

2017-03-01

We propose a model of superdiffusive Lévy walk as an emergent nonlinear phenomenon in systems of interacting individuals. The aim is to provide a qualitative explanation of recent experiments [G. Ariel et al., Nat. Commun. 6, 8396 (2015), 10.1038/ncomms9396] revealing an intriguing behavior: swarming bacteria fundamentally change their collective motion from simple diffusion into a superdiffusive Lévy walk dynamics. We introduce microscopic mean-field kinetic equations in which we combine two key ingredients: (1) alignment interactions between individuals and (2) non-Markovian effects. Our interacting run-and-tumble model leads to the superdiffusive growth of the mean-squared displacement and the power-law distribution of run length with infinite variance. The main result is that the superdiffusive behavior emerges as a cooperative effect without using the standard assumption of the power-law distribution of run distances from the inception. At the same time, we find that the collision and repulsion interactions lead to the density-dependent exponential tempering of power-law distributions. This qualitatively explains the experimentally observed transition from superdiffusion to the diffusion of mussels as their density increases [M. de Jager et al., Proc. R. Soc. B 281, 20132605 (2014), 10.1098/rspb.2013.2605].

Developing a change model for peer worker interventions in mental health services: a qualitative research study.

PubMed

Gillard, S; Gibson, S L; Holley, J; Lucock, M

2015-10-01

A range of peer worker roles are being introduced into mental health services internationally. There is some evidence that attests to the benefits of peer workers for the people they support but formal trial evidence in inconclusive, in part because the change model underpinning peer support-based interventions is underdeveloped. Complex intervention evaluation guidance suggests that understandings of how an intervention is associated with change in outcomes should be modelled, theoretically and empirically, before the intervention can be robustly evaluated. This paper aims to model the change mechanisms underlying peer worker interventions. In a qualitative, comparative case study of ten peer worker initiatives in statutory and voluntary sector mental health services in England in-depth interviews were carried out with 71 peer workers, service users, staff and managers, exploring their experiences of peer working. Using a Grounded Theory approach we identified core processes within the peer worker role that were productive of change for service users supported by peer workers. Key change mechanisms were: (i) building trusting relationships based on shared lived experience; (ii) role-modelling individual recovery and living well with mental health problems; (iii) engaging service users with mental health services and the community. Mechanisms could be further explained by theoretical literature on role-modelling and relationship in mental health services. We were able to model process and downstream outcomes potentially associated with peer worker interventions. An empirically and theoretically grounded change model can be articulated that usefully informs the development, evaluation and planning of peer worker interventions.

Literature search strategies for conducting knowledge-building and theory-generating qualitative systematic reviews.

PubMed

Finfgeld-Connett, Deborah; Johnson, E Diane

2013-01-01

To report literature search strategies for the purpose of conducting knowledge-building and theory-generating qualitative systematic reviews. Qualitative systematic reviews lie on a continuum from knowledge-building and theory-generating to aggregating and summarizing. Different types of literature searches are needed to optimally support these dissimilar reviews. Articles published between 1989-Autumn 2011. These documents were identified using a hermeneutic approach and multiple literature search strategies. Redundancy is not the sole measure of validity when conducting knowledge-building and theory-generating systematic reviews. When conducting these types of reviews, literature searches should be consistent with the goal of fully explicating concepts and the interrelationships among them. To accomplish this objective, a 'berry picking' approach is recommended along with strategies for overcoming barriers to finding qualitative research reports. To enhance integrity of knowledge-building and theory-generating systematic reviews, reviewers are urged to make literature search processes as transparent as possible, despite their complexity. This includes fully explaining and rationalizing what databases were used and how they were searched. It also means describing how literature tracking was conducted and grey literature was searched. In the end, the decision to cease searching also needs to be fully explained and rationalized. Predetermined linear search strategies are unlikely to generate search results that are adequate for purposes of conducting knowledge-building and theory-generating qualitative systematic reviews. Instead, it is recommended that iterative search strategies take shape as reviews evolve. © 2012 Blackwell Publishing Ltd.

Narrative interviews: an important resource in qualitative research.

PubMed

Muylaert, Camila Junqueira; Sarubbi, Vicente; Gallo, Paulo Rogério; Neto, Modesto Leite Rolim

2014-12-01

Objetives This methodological study explain and emphasize the extent and fertility of the narrative interview in qualitative research. Methods To describe the narrative method within the qualitative research. Results The qualitative research method is characterized by addressing issues related to the singularities of the field and individuals investigated, being the narrative interviews a powerful method for use by researchers who aggregate it. They allow the deepening of research, the combination of life stories with socio-historical contexts, making the understanding of the senses that produce changes in the beliefs and values that motivate and justify the actions of possible informants. Conclusion The use of narrative is an advantageous investigative resource in qualitative research, in which the narrative is a traditional form of communication whose purpose is to serve content from which the subjective experiences can be transmitted.

Postpartum depression and culture: Pesado Corazon.

PubMed

Callister, Lynn Clark; Beckstrand, Renea L; Corbett, Cheryl

2010-01-01

The purpose of this article is to describe what the literature has shown about postpartum depression (PPD) in culturally diverse women. The majority of qualitative studies done with women identified as having PPD have been conducted with Western women, with the second largest group focusing on Chinese women. This article reviews the qualitative studies in the literature and discusses how the management of PPD in technocentric and ethnokinship cultures differs. Social support has been shown to be significantly related to fewer symptoms of PPD, and culturally prescribed practices may or may not be cultural mediators in decreasing the incidence of PPD. Nurses should be sensitive to the varied ways in which culturally diverse women perceive, explain, and report symptoms of PPD. Exemplary interventions for culturally diverse women suffering from PPD are examined in this article as well, although it is clear that additional research is needed to develop models for culturally competent interventions for PPD in culturally diverse women and to document the outcomes of such interventions.

Participants' Accounts on Their Decision to Join a Cohort Study With an Attached Biobank: A Qualitative Content Analysis Study Within Two German Studies.

PubMed

Nobile, Hélène; Bergmann, Manuela M; Moldenhauer, Jennifer; Borry, Pascal

2016-07-01

Reliable participation and sustained retention rates are crucial in longitudinal studies involving human subjects and biomaterials. Understanding the decision to enroll is an essential step to develop adequate strategies promoting long-term participation. Semi-structured interviews were implemented with newly recruited and long-term participants randomly drawn from two ongoing longitudinal studies with a biobank component in Germany. Iterative qualitative content analysis was applied to the transcribed interviews. Participants (n = 31) expressed their decision to enroll or remain in the study as the result of the complex interplay of individual factors, institutional cues, study-related features, and societal dynamics. Different forms of trust were identified as central within the elements used to explain participation and could be compared to Dibben, Morris, and Lean's dynamic model of interpersonal trust. Given these high levels of trust, an investigation of the morality of the trustful relationship at stake between participants and research(ers) is warranted. © The Author(s) 2016.

Explaining the Impact of Disabled Children's Engagement with Physical Activity on Their Parents' Smartphone Addiction Levels: A Sequential Explanatory Mixed Methods Research

ERIC Educational Resources Information Center

Gündogdu, Cemal; Aygün, Yalin; Ilkim, Mehmet; Tüfekçi, Sakir

2018-01-01

In this research, quantitative findings and qualitative follow-up themes were used to quantify, conceptualize and finally try to explain the impact of disabled children's engagement with physical activity on their parents' smartphone addiction levels. An initial phase of quantitative investigation was conducted with 116 parents. Analyses of…

Comfort vs risk: a grounded theory about female adolescent behaviour in the sun.

PubMed

Norton, Elizabeth; Holloway, Immy; Galvin, Kathleen

2014-07-01

To generate a grounded theory about female adolescent behaviour in the sun. Nurses have key roles in health promotion and skin cancer prevention. Adolescents' resistance to sun safety messages and their vulnerability to sunburn are of concern internationally. Understanding why young women do as they do in the sun may enhance skin cancer prevention, but their behaviour has not been explained before in the UK. The study incorporated a qualitative grounded theory design using the approach of Glaser. Qualitative data were gleaned from group and one-to-one, semi-structured interviews with 20 female participants aged 14-17, research memos and literature. Sampling was purposive and theoretical. Data collection, analysis and theory generation occurred concurrently. Data were analysed using the constant comparative method. Data collection ended when a substantive theory had been generated. Data analysis revealed five categories of findings: fitting in, being myself, being physically comfortable, slipping up and being comfortable (the core category). The theory generated around the core explains how young women direct their sun-related activities towards meeting their physical and psychosocial comfort needs. A contribution of this research is the grounded theory explaining the behaviour of young women in the sun. Further, the theory challenges assumptions that female adolescents necessarily take risks; it explains their sun-related activities in terms of comfort. The theory extends findings from other researchers' descriptive qualitative studies and also appears to apply to young people in countries other than the UK. Understanding the sun-related activity of young women in terms of physical and psychosocial comfort may help nurses to develop new approaches to skin cancer prevention. These could complement existing messages and humanise health promotion. © 2013 John Wiley & Sons Ltd.

Perceived connections between information and communication technology use and mental symptoms among young adults - a qualitative study.

PubMed

Thomée, Sara; Dellve, Lotta; Härenstam, Annika; Hagberg, Mats

2010-02-12

Prospective associations have been found between high use of information and communication technology (ICT) and reported mental symptoms among young adult university students, but the causal mechanisms are unclear. Our aim was to explore possible explanations for associations between high ICT use and symptoms of depression, sleep disorders, and stress among young adults in order to propose a model of possible pathways to mental health effects that can be tested epidemiologically. We conducted a qualitative interview study with 16 women and 16 men (21-28 years), recruited from a cohort of university students on the basis of reporting high computer (n = 28) or mobile phone (n = 20) use at baseline and reporting mental symptoms at the one-year follow-up. Semi-structured interviews were performed, with open-ended questions about possible connections between the use of computers and mobile phones, and stress, depression, and sleep disturbances. The interview data were analyzed with qualitative content analysis and summarized in a model. Central factors appearing to explain high quantitative ICT use were personal dependency, and demands for achievement and availability originating from the domains of work, study, social life, and individual aspirations. Consequences included mental overload, neglect of other activities and personal needs, time pressure, role conflicts, guilt feelings, social isolation, physical symptoms, worry about electromagnetic radiation, and economic problems. Qualitative aspects (destructive communication and information) were also reported, with consequences including vulnerability, misunderstandings, altered values, and feelings of inadequacy. User problems were a source of frustration. Altered ICT use as an effect of mental symptoms was reported, as well as possible positive effects of ICT on mental health. The concepts and ideas of the young adults with high ICT use and mental symptoms generated a model of possible paths for associations between ICT exposure and mental symptoms. Demands for achievement and availability as well as personal dependency were major causes of high ICT exposure but also direct sources of stress and mental symptoms. The proposed model shows that factors in different domains may have an impact and should be considered in epidemiological and intervention studies.

Perceived connections between information and communication technology use and mental symptoms among young adults - a qualitative study

PubMed Central

2010-01-01

Background Prospective associations have been found between high use of information and communication technology (ICT) and reported mental symptoms among young adult university students, but the causal mechanisms are unclear. Our aim was to explore possible explanations for associations between high ICT use and symptoms of depression, sleep disorders, and stress among young adults in order to propose a model of possible pathways to mental health effects that can be tested epidemiologically. Methods We conducted a qualitative interview study with 16 women and 16 men (21-28 years), recruited from a cohort of university students on the basis of reporting high computer (n = 28) or mobile phone (n = 20) use at baseline and reporting mental symptoms at the one-year follow-up. Semi-structured interviews were performed, with open-ended questions about possible connections between the use of computers and mobile phones, and stress, depression, and sleep disturbances. The interview data were analyzed with qualitative content analysis and summarized in a model. Results Central factors appearing to explain high quantitative ICT use were personal dependency, and demands for achievement and availability originating from the domains of work, study, social life, and individual aspirations. Consequences included mental overload, neglect of other activities and personal needs, time pressure, role conflicts, guilt feelings, social isolation, physical symptoms, worry about electromagnetic radiation, and economic problems. Qualitative aspects (destructive communication and information) were also reported, with consequences including vulnerability, misunderstandings, altered values, and feelings of inadequacy. User problems were a source of frustration. Altered ICT use as an effect of mental symptoms was reported, as well as possible positive effects of ICT on mental health. Conclusions The concepts and ideas of the young adults with high ICT use and mental symptoms generated a model of possible paths for associations between ICT exposure and mental symptoms. Demands for achievement and availability as well as personal dependency were major causes of high ICT exposure but also direct sources of stress and mental symptoms. The proposed model shows that factors in different domains may have an impact and should be considered in epidemiological and intervention studies. PMID:20152023

Understanding knee osteoarthritis from the patients' perspective: a qualitative study.

PubMed

Carmona-Terés, Victoria; Moix-Queraltó, Jenny; Pujol-Ribera, Enriqueta; Lumillo-Gutiérrez, Iris; Mas, Xavier; Batlle-Gualda, Enrique; Gobbo-Montoya, Milena; Jodar-Fernández, Lina; Berenguera, Anna

2017-05-30

No studies of Health Coach Interventions for knee OA sufferers that include patients' perspectives have been published. The study assesses current clinical practice and primary care professionals' advice from the patients' perspective, in order to obtain a participative design for a complex intervention based on coaching psychology. Moreover, wants to analyse the experiences, perceptions, cognitive evaluation, values, emotions, beliefs and coping strategies of patients with knee osteoarthritis, and secondly the impact of these factors in the Self-management of this condition. It is an interpretative qualitative study. The study included patients with diagnosis of knee osteoarthritis (OA) from 4 primary health care centres in Barcelona. A theoretical sampling based on a prior definition of participants' characteristics was carried out. Ten semi-structured interviews with knee OA patients were carried out. A content thematic analysis was performed following a mixed-strategy text codification in Lazarus framework and in emerging codes from the data. The results are structured in two blocks: Experiences and perceptions of informants and Experiences of knee osteoarthritis according to the Lazarus model. Regarding experiences and perceptions of informants: Some participants reported that the information was mostly provided by health professionals. Informants know which food they should eat to lose weight and the benefits of weight loss. Moreover, participants explained that they like walking but that sometimes it is difficult to put into practice. Regarding experiences of knee osteoarthritis according Lazarus model: Cognitive evaluation is influenced by cognitive distortions such as obligation, guilt, dramatization and catastrophism. Family is the value most associated with wellbeing. Helping others is another recurring value. Emotions: Most participants explain that they feel anxiety, irritability or sadness. Beliefs: To some, physiotherapy helps them feel less pain. However, others explain that it is of no use to them. Participants are aware of the association overweight- pain. Coping strategies: The strategies for coping with emotions aim to reduce psychological distress (anxiety, sadness, anger) and some are more active than others. The study highlights that patients with knee osteoarthritis require a person-centered approach that provides them with strategies to overcome the psychological distress caused by this condition.

Exploring the gender gap in the conceptual survey of electricity and magnetism

NASA Astrophysics Data System (ADS)

Henderson, Rachel; Stewart, Gay; Stewart, John; Michaluk, Lynnette; Traxler, Adrienne

2017-12-01

The "gender gap" on various physics conceptual evaluations has been extensively studied. Men's average pretest scores on the Force Concept Inventory and Force and Motion Conceptual Evaluation are 13% higher than women's, and post-test scores are on average 12% higher than women's. This study analyzed the gender differences within the Conceptual Survey of Electricity and Magnetism (CSEM) in which the gender gap has been less well studied and is less consistent. In the current study, data collected from 1407 students (77% men, 23% women) in a calculus-based physics course over ten semesters showed that male students outperformed female students on the CSEM pretest (5%) and post-test (6%). Separate analyses were conducted for qualitative and quantitative problems on lab quizzes and course exams and showed that male students outperformed female students by 3% on qualitative quiz and exam problems. Male and female students performed equally on the quantitative course exam problems. The gender gaps within CSEM post-test scores, qualitative lab quiz scores, and qualitative exam scores were insignificant for students with a CSEM pretest score of 25% or less but grew as pretest scores increased. Structural equation modeling demonstrated that a latent variable, called Conceptual Physics Performance/Non-Quantitative (CPP/NonQnt), orthogonal to quantitative test performance was useful in explaining the differences observed in qualitative performance; this variable was most strongly related to CSEM post-test scores. The CPP/NonQnt of male students was 0.44 standard deviations higher than female students. The CSEM pretest measured CPP/NonQnt much less accurately for women (R2=4 % ) than for men (R2=17 % ). The failure to detect a gender gap for students scoring 25% or less on the pretest suggests that the CSEM instrument itself is not gender biased. The failure to find a performance difference in quantitative test performance while detecting a gap in qualitative performance suggests the qualitative differences do not result from psychological factors such as science anxiety or stereotype threat.

Understanding the relationships between the physical environment and physical activity in older adults: a systematic review of qualitative studies.

PubMed

Moran, Mika; Van Cauwenberg, Jelle; Hercky-Linnewiel, Rachel; Cerin, Ester; Deforche, Benedicte; Plaut, Pnina

2014-07-17

While physical activity (PA) provides many physical, social, and mental health benefits for older adults, they are the least physically active age group. Ecological models highlight the importance of the physical environment in promoting PA. However, results of previous quantitative research revealed inconsistencies in environmental correlates of older adults' PA that may be explained by methodological issues. Qualitative studies can inform and complement quantitative research on environment-PA relationships by providing insight into how and why the environment influences participants' PA behaviors. The current study aimed to provide a systematic review of qualitative studies exploring the potential impact of the physical environment on older adults' PA behaviors. A systematic search was conducted in databases of various disciplines, including: health, architecture and urban planning, transportation, and interdisciplinary databases. From 3,047 articles identified in the physical activity, initial search, 31 articles published from 1996 to 2012 met all inclusion criteria. An inductive content analysis was performed on the extracted findings to identify emerging environmental elements related to older adults' PA. The identified environmental elements were then grouped by study methodologies [indoor interviews (individual or focus groups) vs spatial methods (photo-voice, observations, walk-along interviews)]. This review provides detailed information about environmental factors that potentially influence older adults' PA behaviors. These factors were categorized into five themes: pedestrian infrastructure, safety, access to amenities, aesthetics, and environmental conditions. Environmental factors especially relevant to older adults (i.e., access to facilities, green open spaces and rest areas) tended to emerge more frequently in studies that combined interviews with spatial qualitative methods. Findings showed that qualitative research can provide in-depth information on environmental elements that influence older adults' PA. Future qualitative studies on the physical environment and older adults' PA would benefit from combining interviews with more spatially-oriented methods. Multidisciplinary mixed-methods studies are recommended to establish quantitative relationships complemented with in-depth qualitative information.

Shot noise enhancement from non-equilibrium plasmons in Luttinger liquid junctions.

PubMed

Kim, Jaeuk U; Kinaret, Jari M; Choi, Mahn-Soo

2005-06-29

We consider a quantum wire double junction system with each wire segment described by a spinless Luttinger model, and study theoretically shot noise in this system in the sequential tunnelling regime. We find that the non-equilibrium plasmonic excitations in the central wire segment give rise to qualitatively different behaviour compared to the case with equilibrium plasmons. In particular, shot noise is greatly enhanced by them, and exceeds the Poisson limit. We show that the enhancement can be explained by the emergence of several current-carrying processes, and that the effect disappears if the channels effectively collapse to one because of fast plasmon relaxation processes, for example.

Shot noise enhancement from non-equilibrium plasmons in Luttinger liquid junctions

NASA Astrophysics Data System (ADS)

Kim, Jaeuk U.; Kinaret, Jari M.; Choi, Mahn-Soo

2005-06-01

We consider a quantum wire double junction system with each wire segment described by a spinless Luttinger model, and study theoretically shot noise in this system in the sequential tunnelling regime. We find that the non-equilibrium plasmonic excitations in the central wire segment give rise to qualitatively different behaviour compared to the case with equilibrium plasmons. In particular, shot noise is greatly enhanced by them, and exceeds the Poisson limit. We show that the enhancement can be explained by the emergence of several current-carrying processes, and that the effect disappears if the channels effectively collapse to one because of fast plasmon relaxation processes, for example.

Room temperature exchange bias in multiferroic BiFeO3 nano- and microcrystals with antiferromagnetic core and two-dimensional diluted antiferromagnetic shell

NASA Astrophysics Data System (ADS)

Zhang, Chuang; Wang, Shou Yu; Liu, Wei Fang; Xu, Xun Ling; Li, Xiu; Zhang, Hong; Gao, Ju; Li, De Jun

2017-05-01

Exchange bias (EB) of multiferroics presents many potential opportunities for magnetic devices. However, instead of using low-temperature field cooling in the hysteresis loop measurement, which usually shows an effective approach to obtain obvious EB phenomenon, there are few room temperature EB. In this article, extensive studies on room temperature EB without field cooling were observed in BiFeO3 nano- and microcrystals. Moreover, with increasing size the hysteresis loops shift from horizontal negative exchange bias (NEB) to positive exchange bias (PEB). In order to explain the tunable EB behaviors with size dependence, a phenomenological qualitative model based on the framework of antiferromagnetic (AFM) core-two-dimensional diluted antiferromagnet in a field (2D-DAFF) shell structure was proposed. The training effect (TE) ascertained the validity of model and the presence of unstable magnetic structure using Binek's model. Experimental results show that the tunable EB effect can be explained by the competition of ferromagnetic (FM) exchange coupling and AFM exchange coupling interaction between AFM core and 2D-DAFF shell. Additionally, the local distortion of lattice fringes was observed in hexagonal-shaped BiFeO3 nanocrystals with well-dispersed behavior. The electrical conduction properties agreed well with the space charge-limited conduction mechanism.

Stacking interactions and DNA intercalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dr. Shen; Cooper, Valentino R; Thonhauser, Prof. Timo

2009-01-01

The relationship between stacking interactions and the intercalation of proflavine and ellipticine within DNA is investigated using a nonempirical van der Waals density functional for the correlation energy. Our results, employing a binary stack model, highlight fundamental, qualitative differences between base-pair base-pair interactions and that of the stacked intercalator base pair system. Most notable result is the paucity of torque which so distinctively defines the Twist of DNA. Surprisingly, this model, when combined with a constraint on the twist of the surrounding base-pair steps to match the observed unwinding of the sugar-phosphate backbone, was sufficient for explaining the experimentally observedmore » proflavine intercalator configuration. Our extensive mapping of the potential energy surface of base-pair intercalator interactions can provide valuable information for future nonempirical studies of DNA intercalation dynamics.« less

Multiscale simulations of the early stages of the growth of graphene on copper

NASA Astrophysics Data System (ADS)

Gaillard, P.; Chanier, T.; Henrard, L.; Moskovkin, P.; Lucas, S.

2015-07-01

We have performed multiscale simulations of the growth of graphene on defect-free copper (111) in order to model the nucleation and growth of graphene flakes during chemical vapour deposition and potentially guide future experimental work. Basic activation energies for atomic surface diffusion were determined by ab initio calculations. Larger scale growth was obtained within a kinetic Monte Carlo approach (KMC) with parameters based on the ab initio results. The KMC approach counts the first and second neighbours to determine the probability of surface diffusion. We report qualitative results on the size and shape of the graphene islands as a function of deposition flux. The dominance of graphene zigzag edges for low deposition flux, also observed experimentally, is explained by its larger dynamical stability that the present model fully reproduced.

Qualitative Student Models.

ERIC Educational Resources Information Center

Clancey, William J.

The concept of a qualitative model is used as the focus of this review of qualitative student models in order to compare alternative computational models and to contrast domain requirements. The report is divided into eight sections: (1) Origins and Goals (adaptive instruction, qualitative models of processes, components of an artificial…

Strong fast long-period waves in the Efpalio 2010 earthquake records: explanation in terms of leaking modes

NASA Astrophysics Data System (ADS)

Vackář, Jiří; Zahradník, Jiří; Sokos, Efthimios

2014-01-01

The January 18, 2010, shallow earthquake in the Corinth Gulf, Greece ( M w 5.3) generated unusually strong long-period waves (periods 4-8 s) between the P and S wave arrival. These periods, being significantly longer than the source duration, indicated a structural effect. The waves were observed in epicentral distances 40-250 km and were significant on radial and vertical component. None of existing velocity models of the studied region provided explanation of the waves. By inverting complete waveforms, we obtained an 1-D crustal model explaining the observation. The most significant feature of the best-fitting model (as well as the whole suite of models almost equally well fitting the waveforms) is a strong velocity step at depth about 4 km. In the obtained velocity model, the fast long-period wave was modeled by modal summation and identified as a superposition of several leaking modes. In this sense, the wave is qualitatively similar to P long or Pnl waves, which however are usually reported in larger epicentral distances. The main innovation of this paper is emphasis to smaller epicentral distances. We studied properties of the wave using synthetic seismograms. The wave has a normal dispersion. Azimuthal and distance dependence of the wave partially explains its presence at 46 stations of 70 examined. Depth dependence shows that the studied earthquake was very efficient in the excitation of these waves just due to its shallow centroid depth (4.5 km).

Modelling elderly patients' perception of the community pharmacist image when providing professional services.

PubMed

Sabater-Galindo, Marta; Sabater-Hernández, Daniel; Ruiz de Maya, Salvador; Gastelurrutia, Miguel Angel; Martínez-Martínez, Fernando; Benrimoj, Shalom I

2017-06-01

Professional pharmaceutical services may impact on patient's health behaviour as well as influence on patients' perceptions of the pharmacist image. The Health Belief Model predicts health-related behaviours using patients' beliefs. However, health beliefs (HBs) could transcend beyond predicting health behaviour and may have an impact on the patients' perceptions of the pharmacist image. This study objective was to develop and test a model that relates patients' HBs to patient's perception of the image of the pharmacist, and to assess if the provision of pharmacy services (Intervention group-IG) influences this perception compared to usual care (Control group). A qualitative study was undertaken and a questionnaire was created for the development of the model. The content, dimensions, validity and reliability of the questionnaire were pre-tested qualitatively and in a pilot mail survey. The reliability and validity of the proposed model were tested using Confirmatory Factor Analysis (CFA). Structural Equation Modelling (SEM) was used to explain relationships between dimensions of the final model and to analyse differences between groups. As a result, a final model was developed. CFA concluded that the model was valid and reliable (Goodness of Fit indices: x²(80) = 125.726, p = .001, RMSEA = .04, SRMR = .04, GFI = .997, NFI = .93, CFI = .974). SEM indicated that 'Perceived benefits' were significantly associated with 'Perceived Pharmacist Image' in the whole sample. Differences were found in the IG with also 'Self-efficacy' significantly influencing 'Perceived pharmacist image'. A model of patients' HBs related to their image of the pharmacist was developed and tested. When pharmacists deliver professional services, these services modify some patients' HBs that in turn influence public perception of the pharmacist.

Pushing the Frontier of Data-Oriented Geodynamic Modeling: from Qualitative to Quantitative to Predictive

NASA Astrophysics Data System (ADS)

Liu, L.; Hu, J.; Zhou, Q.

2016-12-01

The rapid accumulation of geophysical and geological data sets poses an increasing demand for the development of geodynamic models to better understand the evolution of the solid Earth. Consequently, the earlier qualitative physical models are no long satisfying. Recent efforts are focusing on more quantitative simulations and more efficient numerical algorithms. Among these, a particular line of research is on the implementation of data-oriented geodynamic modeling, with the purpose of building an observationally consistent and physically correct geodynamic framework. Such models could often catalyze new insights into the functioning mechanisms of the various aspects of plate tectonics, and their predictive nature could also guide future research in a deterministic fashion. Over the years, we have been working on constructing large-scale geodynamic models with both sequential and variational data assimilation techniques. These models act as a bridge between different observational records, and the superposition of the constraining power from different data sets help reveal unknown processes and mechanisms of the dynamics of the mantle and lithosphere. We simulate the post-Cretaceous subduction history in South America using a forward (sequential) approach. The model is constrained using past subduction history, seafloor age evolution, tectonic architecture of continents, and the present day geophysical observations. Our results quantify the various driving forces shaping the present South American flat slabs, which we found are all internally torn. The 3-D geometry of these torn slabs further explains the abnormal seismicity pattern and enigmatic volcanic history. An inverse (variational) model simulating the late Cenozoic western U.S. mantle dynamics with similar constraints reveals a different mechanism for the formation of Yellowstone-related volcanism from traditional understanding. Furthermore, important insights on the mantle density and viscosity structures also emerge from these models.

Polarization recovery in lead zirconate titanate thin films deposited on nanosheets-buffered Si (001)

NASA Astrophysics Data System (ADS)

Chopra, Anuj; Bayraktar, Muharrem; Nijland, Maarten; ten Elshof, Johan E.; Bijkerk, Fred; Rijnders, Guus

2016-12-01

Fatigue behavior of Pb(Zr,Ti)O3 (PZT) films is one of the deterrent factors that limits the use of these films in technological applications. Thus, understanding and minimization of the fatigue behavior is highly beneficial for fabricating reliable devices using PZT films. We have investigated the fatigue behavior of preferentially oriented PZT films deposited on nanosheets-buffered Si substrates using LaNiO3 bottom and top electrodes. The films show fatigue of up to 10% at 100 kHz, whereas no fatigue has been observed at 1 MHz. This frequency dependence of the fatigue behavior is found to be in accordance with Dawber-Scott fatigue model that explains the origin of the fatigue as migration of oxygen vacancies. Interestingly, a partial recovery of remnant polarization up to ˜97% of the maximum value is observed after 4×109 cycles which can be further extended to full recovery by increasing the applied electric field. This full recovery is qualitatively explained using kinetic approach as a manifestation of depinning of domains walls. The understanding of the fatigue behavior and polarization recovery that is explained in this paper can be highly useful in developing more reliable PZT devices.

Qualitative methods in PhD theses from general practice in Scandinavia.

PubMed

Malterud, Kirsti; Hamberg, Katarina; Reventlow, Susanne

2017-12-01

Qualitative methodology is gaining increasing attention and esteem in medical research, with general practice research taking a lead. With these methods, human and social interaction and meaning can be explored and shared by systematic interpretation of text from talk, observation or video. Qualitative studies are often included in Ph.D. theses from general practice in Scandinavia. Still, the Ph.D. programs across nations and institutions offer only limited training in qualitative methods. In this opinion article, we draw upon our observations and experiences, unpacking and reflecting upon values and challenges at stake when qualitative studies are included in Ph.D. theses. Hypotheses to explain these observations are presented, followed by suggestions for standards of evaluation and improvement of Ph.D. programs. The authors conclude that multimethod Ph.D. theses should be encouraged in general practice research, in order to offer future researchers an appropriate toolbox.

Qualitative methods in PhD theses from general practice in Scandinavia

PubMed Central

Malterud, Kirsti; Hamberg, Katarina; Reventlow, Susanne

2017-01-01

Qualitative methodology is gaining increasing attention and esteem in medical research, with general practice research taking a lead. With these methods, human and social interaction and meaning can be explored and shared by systematic interpretation of text from talk, observation or video. Qualitative studies are often included in Ph.D. theses from general practice in Scandinavia. Still, the Ph.D. programs across nations and institutions offer only limited training in qualitative methods. In this opinion article, we draw upon our observations and experiences, unpacking and reflecting upon values and challenges at stake when qualitative studies are included in Ph.D. theses. Hypotheses to explain these observations are presented, followed by suggestions for standards of evaluation and improvement of Ph.D. programs. The authors conclude that multimethod Ph.D. theses should be encouraged in general practice research, in order to offer future researchers an appropriate toolbox. PMID:29094644

Rocket engine diagnostics using qualitative modeling techniques

NASA Technical Reports Server (NTRS)

Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

1992-01-01

Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system has been created. The qualitative model describes the effects of seal failures on the system steady-state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

Rocket engine diagnostics using qualitative modeling techniques

NASA Technical Reports Server (NTRS)

Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

1992-01-01

Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system was created. The qualitative model describes the effects of seal failures on the system steady state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

What is on your mind? Using the perceptual cycle model and critical decision method to understand the decision-making process in the cockpit.

PubMed

Plant, Katherine L; Stanton, Neville A

2013-01-01

Aeronautical decision-making is complex as there is not always a clear coupling between the decision made and decision outcome. As such, there is a call for process-orientated decision research in order to understand why a decision made sense at the time it was made. Schema theory explains how we interact with the world using stored mental representations and forms an integral part of the perceptual cycle model (PCM); proposed here as a way to understand the decision-making process. This paper qualitatively analyses data from the critical decision method (CDM) based on the principles of the PCM. It is demonstrated that the approach can be used to understand a decision-making process and highlights how influential schemata can be at informing decision-making. The reliability of this approach is established, the general applicability is discussed and directions for future work are considered. This paper introduces the PCM, and the associated schema theory, as a framework to structure and explain data collected from the CDM. The reliability of both the method and coding scheme is addressed.

On irreversible adsorption of electron-donating compounds in aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamon, Hajime; Atsushi, Masanori; Okazaki, Morio

Activated carbons and synthetic adsorbents have been used for liquid purification and wastewater treatment. The feasibility of an adsorption process depends greatly on the cost of regeneration of spent adsorbents. If irreversible adsorption occurs, regeneration of spent adsorbent is very difficult. Hence, it is very important to understand why irreversible adsorption appears in aqueous solution. In the adsorption of electron-donating compounds such as phenol, aniline, L-phenylalanine, and L-tyrosine from aqueous solution, irreversibility was observed on activated carbon and graphite. The compounds, except L-tyrosine, were reversibly adsorbed on a synthetic adsorbent. In the case where the carbonaceous adsorbents contacted the aqueousmore » solution containing electron-donating compounds for a long time, the irreversible amount adsorbed increased with the contact time. A two-state adsorption model was used to explain why the irreversible adsorption of electron-donating compound appears in aqueous solution. First, the compound is adsorbed in the precursor state for irreversible adsorption, and then moves into its irreversible state over a potential energy barrier after a long contact time. The appearance of irreversible adsorption was qualitatively explained by the two-state adsorption model.« less

Advanced diffusion MRI and biomarkers in the central nervous system: a new approach.

PubMed

Martín Noguerol, T; Martínez Barbero, J P

The introduction of diffusion-weighted sequences has revolutionized the detection and characterization of central nervous system (CNS) disease. Nevertheless, the assessment of diffusion studies of the CNS is often limited to qualitative estimation. Moreover, the pathophysiological complexity of the different entities that affect the CNS cannot always be correctly explained through classical models. The development of new models for the analysis of diffusion sequences provides numerous parameters that enable a quantitative approach to both diagnosis and prognosis as well as to monitoring the response to treatment; these parameters can be considered potential biomarkers of health and disease. In this update, we review the physical bases underlying diffusion studies and diffusion tensor imaging, advanced models for their analysis (intravoxel coherent motion and kurtosis), and the biological significance of the parameters derived. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Analysis of perceived risk among construction workers: a cross-cultural study and reflection on the Hofstede model.

PubMed

Martinez-Fiestas, Myriam; Rodríguez-Garzón, Ignacio; Delgado-Padial, Antonio; Lucas-Ruiz, Valeriano

2017-09-01

This article presents a cross-cultural study on perceived risk in the construction industry. Worker samples from three different countries were studied: Spain, Peru and Nicaragua. The main goal was to explain how construction workers perceive their occupational hazard and to analyze how this is related to their national culture. The model used to measure perceived risk was the psychometric paradigm. The results show three very similar profiles, indicating that risk perception is independent of nationality. A cultural analysis was conducted using the Hofstede model. The results of this analysis and the relation to perceived risk showed that risk perception in construction is independent of national culture. Finally, a multiple lineal regression analysis was conducted to determine what qualitative attributes could predict the global quantitative size of risk perception. All of the findings have important implications regarding the management of safety in the workplace.

A study of stiffness, residual strength and fatigue life relationships for composite laminates

NASA Technical Reports Server (NTRS)

Ryder, J. T.; Crossman, F. W.

1983-01-01

Qualitative and quantitative exploration of the relationship between stiffness, strength, fatigue life, residual strength, and damage of unnotched, graphite/epoxy laminates subjected to tension loading. Clarification of the mechanics of the tension loading is intended to explain previous contradictory observations and hypotheses; to develop a simple procedure to anticipate strength, fatigue life, and stiffness changes; and to provide reasons for the study of more complex cases of compression, notches, and spectrum fatigue loading. Mathematical models are developed based upon analysis of the damage states. Mathematical models were based on laminate analysis, free body type modeling or a strain energy release rate. Enough understanding of the tension loaded case is developed to allow development of a proposed, simple procedure for calculating strain to failure, stiffness, strength, data scatter, and shape of the stress-life curve for unnotched laminates subjected to tension load.

The effect of primary recoil spectrum on radiation induced segregation in nickel-silicon alloys

NASA Astrophysics Data System (ADS)

Averback, R. S.; Rehn, L. E.; Wagner, W.; Ehrhart, P.

1983-08-01

Segregation of silicon to the surface of Ni-12.7 at% Si alloys during 2.0-MeV He and 3.25-MeV Kr irradiations was measured using Rutherford backscattering spectrometry. For equal calculated defect production rates the Kr irradiation was < 3 % as efficient as the He irradiation for promoting segregation in the temperature range, 450 °C-580 °C. It was further observed that Kr preirradiation of specimens dramatically reduced segregation during subsequent He irradiation. A model for cascade annealing in Ni-Si alloys is presented which qualitatively explains the segregation results. The model assumes that small interstitial-atom-clusters form in individual cascades and that these clusters become trapped at silicon solute atoms. The vacancy thereby becomes the more mobile defect. The model should also have relevance for the observation that void swelling in nickel is suppressed by the addition of silicon solute.

Quantum interference on electron scattering in graphene by carbon impurities in underlying h -BN

NASA Astrophysics Data System (ADS)

Kaneko, Tomoaki; Koshino, Mikito; Saito, Riichiro

2017-03-01

Electronic structures and transport properties of graphene on h -BN with carbon impurities are investigated by first-principles calculation and the tight-binding model. We show that the coupling between the impurity level and the graphene's Dirac cone sensitively depends on the impurity position, and in particular, it nearly vanishes when the impurity is located right below the center of the six membered ring of graphene. The Bloch phase factor at the Brillouin zone edge plays a decisive role in the cancellation of the hopping integrals. The impurity position dependence on the electronic structures of graphene on h -BN is investigated by the first-principles calculation, and its qualitative feature is well explained by a tight-binding model with graphene and a single impurity site. We also propose a simple one-dimensional chain-impurity model to analytically describe the role of the quantum interference in the position-dependent coupling.

A Ball Lightning Model as a Possible Explanation of Recently Reported Cavity Lights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fryberger, David; /SLAC

The salient features of cavity lights, in particular, mobile luminous objects (MLO's), as have been experimentally observed in superconducting accelerator cavities, are summarized. A model based upon standard electromagnetic interactions between a small particle and the 1.5 GHz cavity excitation field is described. This model can explain some features of these data, in particular, the existence of particle orbits without wall contact. While this result is an important success for the model, it is detailed why the model as it stands is incomplete. It is argued that no avenues for a suitable extension of the model through established physics appearmore » evident, which motivates an investigation of a model based upon a more exotic object, ball lightning. As discussed, further motivation derives from the fact that there are significant similarities in many of the qualitative features of ball lightning and MLO's, even though they appear in quite different circumstances and differ in scale by orders of magnitude. The ball lightning model, which incorporates electromagnetic charges and currents, is based on a symmetrized set of Maxwell's equations in which the electromagnetic sources and fields are characterized by a process called dyality rotation. It is shown that a consistent mathematical description of dyality rotation as a physical process can be achieved by adding suitable (phenomenological) current terms to supplement the usual current terms in the symmetrized Maxwell's equations. These currents, which enable the conservation of electric and magnetic charge, are called vacuum currents. It is shown that the proposed ball lightning model offers a good qualitative explanation of the perplexing aspects of the MLO data. Avenues for further study are indicated.« less

Latent constructs model explaining the attachment-linked variation in autobiographical remembering.

PubMed

Öner, Sezin; Gülgöz, Sami

2016-01-01

In the current study, we proposed a latent constructs model to characterise the qualitative aspects of autobiographical remembering and investigated the structural relations in the model that may vary across individuals. Primarily, we focused on the memories of romantic relationships and argued that attachment anxiety and avoidance would be reflected in the ways that individuals encode, rehearse, or remember autobiographical memories in close relationships. Participants reported two positive and two negative relationship-specific memories and rated the characteristics for each memory. As predicted, the basic memory model yielded appropriate fit, indicating that event characteristics (EC) predicted the frequency of rehearsal (RC) and phenomenology at retrieval (PC). When attachment variables were integrated, the model showed that rehearsal mediated the link between anxiety and PC, especially for negative memories. On the other hand, for avoidance EC was the key factor mediating the link between avoidance and RC, as well as PC. Findings were discussed with respect to autobiographical memory functions emphasising a systematically, integrated framework.

``Physics with a Smile''-Explaining Phenomena with a Qualitative Problem-Solving Strategy

NASA Astrophysics Data System (ADS)

Mualem, Roni; Eylon, Bat-Sheva

2007-03-01

Various studies indicate that high school physics students and even college students majoring in physics have difficulties in qualitative understanding of basic concepts and principles of physics.1-5 For example, studies carried out with the Force Concept Inventory (FCI)1,6 illustrate that qualitative tasks are not easy to solve even at the college level. Consequently, "conceptual physics" courses have been designed to foster qualitative understanding, and advanced high school physics courses as well as introductory college-level courses strive to develop qualitative understanding. Many physics education researchers emphasize the importance of acquiring some qualitative understanding of basic concepts in physics as early as middle school or in the context of courses that offer "Physics First" in the ninth grade before biology or chemistry.7 This trend is consistent with the call to focus the science curriculum on a small number of basic concepts and ideas, and to instruct students in a more "meaningful way" leading to better understanding. Studies7-10 suggest that familiar everyday contexts (see Fig. 1) are useful in fostering qualitative understanding.

Spin-wave resonances and surface spin pinning in Ga1-xMnxAs thin films

NASA Astrophysics Data System (ADS)

Bihler, C.; Schoch, W.; Limmer, W.; Goennenwein, S. T. B.; Brandt, M. S.

2009-01-01

We investigate the dependence of the spin-wave resonance (SWR) spectra of Ga0.95Mn0.05As thin films on the sample treatment. We find that for the external magnetic field perpendicular to the film plane, the SWR spectrum of the as-grown thin films and the changes upon etching and short-term hydrogenation can be quantitatively explained via a linear gradient in the uniaxial magnetic anisotropy field in growth direction. The model also qualitatively explains the SWR spectra observed for the in-plane easy-axis orientation of the external magnetic field. Furthermore, we observe a change in the effective surface spin pinning of the partially hydrogenated sample, which results from the tail in the hydrogen-diffusion profile. The latter leads to a rapidly changing hole concentration/magnetic anisotropy profile acting as a barrier for the spin-wave excitations. Therefore, short-term hydrogenation constitutes a simple method to efficiently manipulate the surface spin pinning.

Charge ordering in ionic fluids mediate repulsive surface interactions

NASA Astrophysics Data System (ADS)

Dasbiswas, Kinjal; Ludwig, Nicholas B.; Zhang, Hao; Talapin, Dmitri; Vaikuntanathan, Suri

Recent experiments on ionic fluids, such as surface force measurements in organic ionic liquids and the observation of colloidal stability in inorganic molten salts, suggest the presence of long-ranged repulsive forces. These cannot be explained within the classical Debye-Hückel theory for dilute electrolytes. We argue that such repulsive interactions can arise from long-range (several nm) charge density oscillations induced by a surface that preferentially binds one of the ionic species in an ionic fluid. We present a continuum theory that accounts for such charge layering based on a frustrated Ising model that incorporates both long-range Coulombic and short-range steric interactions. The mean-field analytic treatment qualitatively matches results from molecular simulations. A careful analysis of the ionic correlation functions arising from such charge ordering may also explain the long electrostatic screening lengths observed in various ionic fluids and their non-monotonic dependence on the electrolyte concentration. We acknowledge the University of Chicago for support.

A permeation theory for single-file ion channels: one- and two-step models.

PubMed

Nelson, Peter Hugo

2011-04-28

How many steps are required to model permeation through ion channels? This question is investigated by comparing one- and two-step models of permeation with experiment and MD simulation for the first time. In recent MD simulations, the observed permeation mechanism was identified as resembling a Hodgkin and Keynes knock-on mechanism with one voltage-dependent rate-determining step [Jensen et al., PNAS 107, 5833 (2010)]. These previously published simulation data are fitted to a one-step knock-on model that successfully explains the highly non-Ohmic current-voltage curve observed in the simulation. However, these predictions (and the simulations upon which they are based) are not representative of real channel behavior, which is typically Ohmic at low voltages. A two-step association/dissociation (A/D) model is then compared with experiment for the first time. This two-parameter model is shown to be remarkably consistent with previously published permeation experiments through the MaxiK potassium channel over a wide range of concentrations and positive voltages. The A/D model also provides a first-order explanation of permeation through the Shaker potassium channel, but it does not explain the asymmetry observed experimentally. To address this, a new asymmetric variant of the A/D model is developed using the present theoretical framework. It includes a third parameter that represents the value of the "permeation coordinate" (fractional electric potential energy) corresponding to the triply occupied state n of the channel. This asymmetric A/D model is fitted to published permeation data through the Shaker potassium channel at physiological concentrations, and it successfully predicts qualitative changes in the negative current-voltage data (including a transition to super-Ohmic behavior) based solely on a fit to positive-voltage data (that appear linear). The A/D model appears to be qualitatively consistent with a large group of published MD simulations, but no quantitative comparison has yet been made. The A/D model makes a network of predictions for how the elementary steps and the channel occupancy vary with both concentration and voltage. In addition, the proposed theoretical framework suggests a new way of plotting the energetics of the simulated system using a one-dimensional permeation coordinate that uses electric potential energy as a metric for the net fractional progress through the permeation mechanism. This approach has the potential to provide a quantitative connection between atomistic simulations and permeation experiments for the first time.

A meta-ethnography of patients' experiences of chronic pelvic pain: struggling to construct chronic pelvic pain as 'real'.

PubMed

Toye, Francine; Seers, Kate; Barker, Karen

2014-12-01

To review systematically and integrate the findings of qualitative research to increase our understanding of patients' experiences of chronic pelvic pain. Chronic pelvic pain is a prevalent pain condition with a high disease burden for men and women. Its multifactorial nature makes it challenging for clinicians and patients. Synthesis of qualitative research using meta-ethnography. Five electronic bibliographic databases from inception until March 2014 supplemented by citation tracking. Of 488 papers retrieved, 32 met the review aim. Central to meta-ethnography is identifying 'concepts' and developing a conceptual model through constant comparison. Concepts are the primary data of meta-ethnography. Two team members read each paper to identify and collaboratively describe the concepts. We next compared concepts across studies and organized them into categories with shared meaning. Finally, we developed a conceptual model, or line of argument, to explain the conceptual categories. Our findings incorporate the following categories into a conceptual model: relentless and overwhelming pain; threat to self; unpredictability, struggle to construct pain as normal or pathological; a culture of secrecy; validation by diagnosis; ambiguous experience of health care; elevation of experiential knowledge and embodiment of knowledge through a community. The innovation of our model is to demonstrate, for the first time, the central struggle to construct 'pathological' vs. 'normal' chronic pelvic pain, a struggle that is exacerbated by a culture of secrecy. More research is needed to explore men's experience and to compare this with women's experience. © 2014 John Wiley & Sons Ltd.

The effects of temperature on the stability of a neuronal oscillator.

PubMed

Rinberg, Anatoly; Taylor, Adam L; Marder, Eve

2013-01-01

The crab Cancer borealis undergoes large daily fluctuations in environmental temperature (8-24°C) and must maintain appropriate neural function in the face of this perturbation. In the pyloric circuit of the crab stomatogastric ganglion, we pharmacologically isolated the pacemaker kernel (the AB and PD neurons) and characterized its behavior in response to temperature ramps from 7°C to 31°C. For moderate temperatures, the pacemaker displayed a frequency-temperature curve statistically indistinguishable from that of the intact circuit, and like the intact circuit maintained a constant duty cycle. At high temperatures (above 23°C), a variety of different behaviors were seen: in some preparations the pacemaker increased in frequency, in some it slowed, and in many preparations the pacemaker stopped oscillating ("crashed"). Furthermore, these crashes seemed to fall into two qualitatively different classes. Additionally, the animal-to-animal variability in frequency increased at high temperatures. We used a series of Morris-Lecar mathematical models to gain insight into these phenomena. The biophysical components of the final model have temperature sensitivities similar to those found in nature, and can crash via two qualitatively different mechanisms that resemble those observed experimentally. The crash type is determined by the precise parameters of the model at the reference temperature, 11°C, which could explain why some preparations seem to crash in one way and some in another. Furthermore, even models with very similar behavior at the reference temperature diverge greatly at high temperatures, resembling the experimental observations.

A Mixed Mode Cochlear Amplifier Including Neural Feedback

NASA Astrophysics Data System (ADS)

Flax, Matthew R.; Holmes, W. Harvey

2011-11-01

The mixed mode cochlear amplifier (MMCA) model is derived from the physiology of the cochlea. It is comprised of three main elements of the peripheral hearing system: the cochlear mechanics, hair cell motility, and neurophysiology. This model expresses both active compression wave and active traveling wave modes of operation. The inclusion of a neural loop with a time delay, and a new paradigm for the mechanical response of the outer hair cells, are believed to be unique features of the MMCA. These elements combine to form an active feedback loop to constitute the cochlear amplifier, whose input is a passive traveling wave vibration. The result is a cycle-by-cycle amplifier with nonlinear response. This system can assume an infinite number of different operating states. The stable state and the first few amplitude-limited unstable (Hopf-bifurcated) states are significant in describing the operation of the peripheral hearing system. A hierarchy of models can be constructed from this concept, depending on the amount of detail included. The simplest model of the MMCA is a nonlinear delay line resonator. It was found that even this simple MMCA version can explain a large number of hearing phenomena, at least qualitatively. This paper concentrates on explaining the fractional octave shift from the living to postmortem response in terms of the new model. Other mechanical, hair cell and neurological phenomena can also be accounted for by the MMCA, including two-tone suppression behavior, distortion product responses, otoacoustic emissions and neural spontaneous rates.

Probabilistic prediction of barrier-island response to hurricanes

USGS Publications Warehouse

Plant, Nathaniel G.; Stockdon, Hilary F.

2012-01-01

Prediction of barrier-island response to hurricane attack is important for assessing the vulnerability of communities, infrastructure, habitat, and recreational assets to the impacts of storm surge, waves, and erosion. We have demonstrated that a conceptual model intended to make qualitative predictions of the type of beach response to storms (e.g., beach erosion, dune erosion, dune overwash, inundation) can be reformulated in a Bayesian network to make quantitative predictions of the morphologic response. In an application of this approach at Santa Rosa Island, FL, predicted dune-crest elevation changes in response to Hurricane Ivan explained about 20% to 30% of the observed variance. An extended Bayesian network based on the original conceptual model, which included dune elevations, storm surge, and swash, but with the addition of beach and dune widths as input variables, showed improved skill compared to the original model, explaining 70% of dune elevation change variance and about 60% of dune and shoreline position change variance. This probabilistic approach accurately represented prediction uncertainty (measured with the log likelihood ratio), and it outperformed the baseline prediction (i.e., the prior distribution based on the observations). Finally, sensitivity studies demonstrated that degrading the resolution of the Bayesian network or removing data from the calibration process reduced the skill of the predictions by 30% to 40%. The reduction in skill did not change conclusions regarding the relative importance of the input variables, and the extended model's skill always outperformed the original model.

An Individualized Approach to Introductory Physics

ERIC Educational Resources Information Center

Rigden, John S.

1970-01-01

Explains individualization of a physics course in terms of organization, testing, and philosophy. Organization of laboratory and lecture is focused on two topics, classical mechanics and relativity theory. The testing consists of quantitative and qualitative questions. (DS)

The Policies, Politics, and Players in the North Carolina Parental School Choice Voucher Debate: Why Wisconsin Said Yes, but North Carolina Says No

ERIC Educational Resources Information Center

Haire, Rita C.

2010-01-01

This qualitative study examines the education policies, political dynamics, and key players in Wisconsin (WI) and North Carolina (NC) to develop a theory to explain how a targeted parental school choice voucher policy was legislated in WI but not in NC. The study seeks to offer a theoretical policy framework that explains the absence of a targeted…

Self-calibrating models for dynamic monitoring and diagnosis

NASA Technical Reports Server (NTRS)

Kuipers, Benjamin

1994-01-01

The present goal in qualitative reasoning is to develop methods for automatically building qualitative and semiquantitative models of dynamic systems and to use them for monitoring and fault diagnosis. The qualitative approach to modeling provides a guarantee of coverage while our semiquantitative methods support convergence toward a numerical model as observations are accumulated. We have developed and applied methods for automatic creation of qualitative models, developed two methods for obtaining tractable results on problems that were previously intractable for qualitative simulation, and developed more powerful methods for learning semiquantitative models from observations and deriving semiquantitative predictions from them. With these advances, qualitative reasoning comes significantly closer to realizing its aims as a practical engineering method.

Qualitative models for space system engineering

NASA Technical Reports Server (NTRS)

Forbus, Kenneth D.

1990-01-01

The objectives of this project were: (1) to investigate the implications of qualitative modeling techniques for problems arising in the monitoring, diagnosis, and design of Space Station subsystems and procedures; (2) to identify the issues involved in using qualitative models to enhance and automate engineering functions. These issues include representing operational criteria, fault models, alternate ontologies, and modeling continuous signals at a functional level of description; and (3) to develop a prototype collection of qualitative models for fluid and thermal systems commonly found in Space Station subsystems. Potential applications of qualitative modeling to space-systems engineering, including the notion of intelligent computer-aided engineering are summarized. Emphasis is given to determining which systems of the proposed Space Station provide the most leverage for study, given the current state of the art. Progress on using qualitative models, including development of the molecular collection ontology for reasoning about fluids, the interaction of qualitative and quantitative knowledge in analyzing thermodynamic cycles, and an experiment on building a natural language interface to qualitative reasoning is reported. Finally, some recommendations are made for future research.

Surface waves on a soft viscoelastic layer produced by an oscillating microbubble.

PubMed

Tinguely, Marc; Hennessy, Matthew G; Pommella, Angelo; Matar, Omar K; Garbin, Valeria

2016-05-14

Ultrasound-driven bubbles can cause significant deformation of soft viscoelastic layers, for instance in surface cleaning and biomedical applications. The effect of the viscoelastic properties of a boundary on the bubble-boundary interaction has been explored only qualitatively, and remains poorly understood. We investigate the dynamic deformation of a viscoelastic layer induced by the volumetric oscillations of an ultrasound-driven microbubble. High-speed video microscopy is used to observe the deformation produced by a bubble oscillating at 17-20 kHz in contact with the surface of a hydrogel. The localised oscillating pressure applied by the bubble generates surface elastic (Rayleigh) waves on the gel, characterised by elliptical particle trajectories. The tilt angle of the elliptical trajectories varies with increasing distance from the bubble. Unexpectedly, the direction of rotation of the surface elements on the elliptical trajectories shifts from prograde to retrograde at a distance from the bubble that depends on the viscoelastic properties of the gel. To explain these behaviours, we develop a simple three-dimensional model for the deformation of a viscoelastic solid by a localised oscillating force. By using as input for the model the values of the shear modulus obtained from the propagation velocity of the Rayleigh waves, we find good qualitative agreement with the experimental observations.

Energy balance and stability. [in stellar coronae

NASA Technical Reports Server (NTRS)

Hammer, R.

1982-01-01

The energy balance of the outer atmospheres of solarlike stars is discussed. The energy balance of open coronal regions is considered, discussing the construction and characteristics of models of such regions in some detail. In particular, the temperature as a function of height is considered, as are the damping length dependence of the global energy balance in the region between the base of the transition region and the critical point, and the effects of changing the amount of coronal heating, the stellar mass, and the stellar radius. Models of coronal loops are more briefly discussed. The chromosphere is then included in the discussion of the energy balance, and the connection between global energy balance and global thermal stability is addressed. The observed positive correlations between the chromospheric and coronal energy losses and the pressure of the transition region is qualitatively explained.

Stable Eigenmodes and Energy Dynamics in a Model of LAPD Turbulence

NASA Astrophysics Data System (ADS)

Friedman, Brett; Carter, T. A.; Umansky, M. V.

2011-10-01

A three field Braginskii fluid model that semi-quantitatively predicts turbulent statistics in the Large Plasma Device (LAPD) at UCLA is analyzed. A 3D simulation of turbulence in LAPD using the BOUT++ fluid code is shown to reproduce experimental turbulent properties such as the frequency spectrum and correlation length with semi-qualitative and semi-quantitative accuracy. In an attempt to explain turbulent saturation in the simulation, equations for the energy dynamics are derived and applied to the results. The degree to which stable linear drift wave eigenmodes draw energy from the system and the affect that zonal flows have on transferring energy to stable eigenmode branches is explored. It is also shown that zonal flows drive Kelvin-Helmholtz flute modes, which come to dominate the energy dynamics in the quasi steady state regime.

How Qualitative Methods Can be Used to Inform Model Development.

PubMed

Husbands, Samantha; Jowett, Susan; Barton, Pelham; Coast, Joanna

2017-06-01

Decision-analytic models play a key role in informing healthcare resource allocation decisions. However, there are ongoing concerns with the credibility of models. Modelling methods guidance can encourage good practice within model development, but its value is dependent on its ability to address the areas that modellers find most challenging. Further, it is important that modelling methods and related guidance are continually updated in light of any new approaches that could potentially enhance model credibility. The objective of this article was to highlight the ways in which qualitative methods have been used and recommended to inform decision-analytic model development and enhance modelling practices. With reference to the literature, the article discusses two key ways in which qualitative methods can be, and have been, applied. The first approach involves using qualitative methods to understand and inform general and future processes of model development, and the second, using qualitative techniques to directly inform the development of individual models. The literature suggests that qualitative methods can improve the validity and credibility of modelling processes by providing a means to understand existing modelling approaches that identifies where problems are occurring and further guidance is needed. It can also be applied within model development to facilitate the input of experts to structural development. We recommend that current and future model development would benefit from the greater integration of qualitative methods, specifically by studying 'real' modelling processes, and by developing recommendations around how qualitative methods can be adopted within everyday modelling practice.

Qualitative, semi-quantitative, and quantitative simulation of the osmoregulation system in yeast

PubMed Central

Pang, Wei; Coghill, George M.

2015-01-01

In this paper we demonstrate how Morven, a computational framework which can perform qualitative, semi-quantitative, and quantitative simulation of dynamical systems using the same model formalism, is applied to study the osmotic stress response pathway in yeast. First the Morven framework itself is briefly introduced in terms of the model formalism employed and output format. We then built a qualitative model for the biophysical process of the osmoregulation in yeast, and a global qualitative-level picture was obtained through qualitative simulation of this model. Furthermore, we constructed a Morven model based on existing quantitative model of the osmoregulation system. This model was then simulated qualitatively, semi-quantitatively, and quantitatively. The obtained simulation results are presented with an analysis. Finally the future development of the Morven framework for modelling the dynamic biological systems is discussed. PMID:25864377

Why Open-Ended Survey Questions Are Unlikely to Support Rigorous Qualitative Insights.

PubMed

LaDonna, Kori A; Taylor, Taryn; Lingard, Lorelei

2018-03-01

Health professions education researchers are increasingly relying on a combination of quantitative and qualitative research methods to explore complex questions in the field. This important and necessary development, however, creates new methodological challenges that can affect both the rigor of the research process and the quality of the findings. One example is "qualitatively" analyzing free-text responses to survey or assessment instrument questions. In this Invited Commentary, the authors explain why analysis of such responses rarely meets the bar for rigorous qualitative research. While the authors do not discount the potential for free-text responses to enhance quantitative findings or to inspire new research questions, they caution that these responses rarely produce data rich enough to generate robust, stand-alone insights. The authors consider exemplars from health professions education research and propose strategies for treating free-text responses appropriately.

Iterative categorization (IC): a systematic technique for analysing qualitative data

PubMed Central

2016-01-01

Abstract The processes of analysing qualitative data, particularly the stage between coding and publication, are often vague and/or poorly explained within addiction science and research more broadly. A simple but rigorous and transparent technique for analysing qualitative textual data, developed within the field of addiction, is described. The technique, iterative categorization (IC), is suitable for use with inductive and deductive codes and can support a range of common analytical approaches, e.g. thematic analysis, Framework, constant comparison, analytical induction, content analysis, conversational analysis, discourse analysis, interpretative phenomenological analysis and narrative analysis. Once the data have been coded, the only software required is a standard word processing package. Worked examples are provided. PMID:26806155

Patients' expectations of the role of the community pharmacist: Development and testing of a conceptual model.

PubMed

Sabater-Galindo, Marta; Ruiz de Maya, Salvador; Benrimoj, Shalom I; Gastelurrutia, Miguel Angel; Martínez-Martínez, Fernando; Sabater-Hernández, Daniel

The roles of community pharmacists are evolving to include provision of expanded professional pharmacy services, thus leading to an increased interest in pharmacist-patient interactions. Role theory can be used to explain the interaction between this pair of individuals, by focusing on the roles performed by each one. To develop and test a model that relates patients' image of the pharmacist to their expectations of pharmacist's role, and how this then influences patients' reactions toward the pharmacist's role. A qualitative study was undertaken, and a questionnaire was created for the development of the model, based on role theory. The content, dimensions, validity and reliability of the questionnaire were pre-tested qualitatively and in a pilot mail survey. The reliability and validity of the proposed model were tested using confirmatory factor analysis (CFA). Structural equation modelling (SEM) was used to explain relationships between dimensions of the final model. A final model was developed. CFA concluded that the model was valid and reliable (Goodness of Fit indices: χ 2 (109) = 227.662, P = 0.000, RMSEA = 0.05, SRMR = 0.05, GFI = 1.00, NNFI = 0.90, CFI = 0.92). SEM indicated that "perceived pharmacist image" was associated positively and significantly with both "professional expectations" (the standardized path coefficient of (H) = 0.719, P < 0.05), as well as "courtesy expectations" (the standardized path coefficient of (H) = 0.582, P < 0.05). At the same time, "professional expectations" were associated positively and significantly with "positive reactions" (the standardized path coefficient of (H) = 0.358, P < 0.05), but negatively with "Negative reactions" (the standardized path coefficient of (H) = -0.427, P < 0.05). "Courtesy expectations" were associated positively and significantly with "positive reactions" (the standardized path coefficient of (H) = 0.081, P < 0.05), as well as "negative reactions" (the standardized path coefficient of (H) = 0.450, P < 0.05). A valid and reliable model of patients' image of the pharmacist related to their expectations and reactions to the pharmacist's role was developed and tested. When the perceived image of the pharmacist is enhanced, patients' expectations of the pharmacist are heightened; in turn, these expectations were associated with reactions of patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Metallicity-dependent kinematics and morphology of the Milky Way bulge

NASA Astrophysics Data System (ADS)

Athanassoula, E.; Rodionov, S. A.; Prantzos, N.

2017-05-01

We use N-body chemo-dynamic simulations to study the coupling between morphology, kinematics and metallicity of the bar/bulge region of our Galaxy. We make qualitative comparisons of our results with available observations and find very good agreement. We conclude that this region is complex, since it comprises several stellar components with different properties - I.e. a boxy/peanut bulge, thin and thick disc components, and, to lesser extents, a disky pseudo-bulge, a stellar halo and a small classical bulge - all cohabiting in dynamical equilibrium. Our models show strong links between kinematics and metallicity, or morphology and metallicity, as already suggested by a number of recent observations. We discuss and explain these links.

Dissipation in a rotating frame: Master equation, effective temperature, and Lamb shift

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verso, Alvise; Ankerhold, Joachim

Motivated by recent realizations of microwave-driven nonlinear resonators in superconducting circuits, the impact of environmental degrees of freedom is analyzed as seen from a rotating frame. A system plus reservoir model is applied to consistently derive in the weak coupling limit the master equation for the reduced density in the moving frame and near the first bifurcation threshold. The concept of an effective temperature is introduced to analyze to what extent a detailed balance relation exists. Explicit expressions are also found for the Lamb-shift. Results for ohmic baths are in agreement with experimental findings, while for structured environments population inversionmore » is predicted that may qualitatively explain recent observations.« less

New Approach to Image Aerogels by Scanning Electron Microscopy

NASA Astrophysics Data System (ADS)

Solá, Francisco; Hurwitz, Frances; Yang, Jijing

2011-03-01

A new scanning electron microscopy (SEM) technique to image poor electrically conductive aerogels is presented. The process can be performed by non-expert SEM users. We showed that negative charging effects on aerogels can be minimized significantly by inserting dry nitrogen gas close to the region of interest. The process involves the local recombination of accumulated negative charges with positive ions generated from ionization processes. This new technique made possible the acquisition of images of aerogels with pores down to approximately 3nm in diameter using a positively biased Everhart-Thornley (E-T) detector. Well-founded concepts based on known models will also be presented with the aim to explain the results qualitatively.

Pleasure, power, and inequality: incorporating sexuality into research on contraceptive use.

PubMed

Higgins, Jenny A; Hirsch, Jennifer S

2008-10-01

We know surprisingly little about how contraception affects sexual enjoyment and functioning (and vice versa), particularly for women. What do people seek from sex, and how do sexual experiences shape contraceptive use? We draw on qualitative data to make 3 points. First, pleasure varies. Both women and men reported multiple aspects of enjoyment, of which physical pleasure was only one. Second, pleasure matters. Clear links exist between the forms of pleasure respondents seek and their contraceptive practices. Third, pleasure intersects with power and social inequality. Both gender and social class shape sexual preferences and contraceptive use patterns. These findings call for a reframing of behavioral models that explain why people use (or do not use) contraception.

Tuning the critical solution temperature of polymers by copolymerization

NASA Astrophysics Data System (ADS)

Schulz, Bernhard; Chudoba, Richard; Heyda, Jan; Dzubiella, Joachim

2015-12-01

We study statistical copolymerization effects on the upper critical solution temperature (CST) of generic homopolymers by means of coarse-grained Langevin dynamics computer simulations and mean-field theory. Our systematic investigation reveals that the CST can change monotonically or non-monotonically with copolymerization, as observed in experimental studies, depending on the degree of non-additivity of the monomer (A-B) cross-interactions. The simulation findings are confirmed and qualitatively explained by a combination of a two-component Flory-de Gennes model for polymer collapse and a simple thermodynamic expansion approach. Our findings provide some rationale behind the effects of copolymerization and may be helpful for tuning CST behavior of polymers in soft material design.

Pre-service primary school teachers’ abilities in explaining water and air pollution scientifically

NASA Astrophysics Data System (ADS)

Lukmannudin; Sopandi, W.; Sujana, A.; Sukardi, R.

2018-05-01

The purpose of this study is to determine the ability of pre-service primary school teachers (PSPST) in explaining the phenomenon of water and air pollution scientifically. The research method used descriptive method of analysis with qualitative approach. The respondents were PSPTP at 4th semester. This study used a four-tier instrument diagnostic test. The number of subjects was 84 PSPTP at Universitas Pendidikan Indonesia, Kampus Daerah Sumedang. The results demonstrate the ability of PSPST in explaining water and air pollution scientifically. The results show that only 6% of PSPST who are able to explain the phenomenon of water pollution and only 4% of PSPST who are able to explain the phenomenon of air pollution. The fact should be attention for PSPST because these understanding are crucial in the process of learning activities in the classroom.

Understanding practice change in community pharmacy: a qualitative research instrument based on organisational theory.

PubMed

Roberts, Alison S; Hopp, Trine; Sørensen, Ellen Westh; Benrimoj, Shalom I; Chen, Timothy F; Herborg, Hanne; Williams, Kylie; Aslani, Parisa

2003-10-01

The past decade has seen a notable shift in the practice of pharmacy, with a strong focus on the provision of cognitive pharmaceutical services (CPS) by community pharmacists. The benefits of these services have been well documented, yet their uptake appears to be slow. Various strategies have been developed to overcome barriers to the implementation of CPS, with varying degrees of success, and little is known about the sustainability of the practice changes they produce. Furthermore, the strategies developed are often specific to individual programs or services, and their applicability to other CPS has not been explored. There seems to be a need for a flexible change management model for the implementation and dissemination of a range of CPS, but before it can be developed, a better understanding of the change process is required. This paper describes the development of a qualitative research instrument that may be utilised to investigate practice change in community pharmacy. Specific objectives included gaining knowledge about the circumstances surrounding attempts to implement CPS, and understanding relationships that are important to the change process. Organisational theory provided the conceptual framework for development of the qualitative research instrument, within which two theories were used to give insight into the change process: Borum's theory of organisational change, which categorizes change strategies as rational, natural, political or open; and Social Network Theory, which helps identify and explain the relationships between key people involved in the change process. A semi-structured affecting practice change found in the literature that warranted further investigation with the theoretical perspectives of organisational change and social networks. To address the research objectives, the instrument covered four broad themes: roles, experiences, strategies and networks. The qualitative research instrument developed in this study provides a starting point for future research to lead to a description and understanding of practice change in community pharmacy, and subsequent development of models for the sustainable implementation of CPS.

Using secondary analysis of qualitative data of patient experiences of health care to inform health services research and policy.

PubMed

Ziebland, Sue; Hunt, Kate

2014-07-01

Qualitative research is recognized as an important method for including patients' voices and experiences in health services research and policy-making, yet the considerable potential to analyse existing qualitative data to inform health policy and practice has been little realized. This failure may partly be explained by: a lack of awareness amongst health policy makers of the increasing wealth of qualitative data available; and around 15 years of internal debates among qualitative researchers on the strengths, limitations and validity of re-use of qualitative data. Whilst acknowledging the challenges of qualitative secondary data analysis, we argue that there is a growing imperative to be pragmatic and to undertake analysis of existing qualitative data collections where they have the potential to contribute to health policy formulation. Time pressures are inherent in the policy-making process and in many circumstances it is not possible to seek funding, conduct and analyse new qualitative studies of patients' experiences in time to inform a specific policy. The danger then is that the patient voice, and the experiences of relatives and carers, is either excluded or included in a way that is easily dismissed as 'unrepresentative'. We argue that secondary analysis of qualitative data collections may sometimes be an effective means to enable patient experiences to inform policy decision-making. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

The perception of probability.

PubMed

Gallistel, C R; Krishan, Monika; Liu, Ye; Miller, Reilly; Latham, Peter E

2014-01-01

We present a computational model to explain the results from experiments in which subjects estimate the hidden probability parameter of a stepwise nonstationary Bernoulli process outcome by outcome. The model captures the following results qualitatively and quantitatively, with only 2 free parameters: (a) Subjects do not update their estimate after each outcome; they step from one estimate to another at irregular intervals. (b) The joint distribution of step widths and heights cannot be explained on the assumption that a threshold amount of change must be exceeded in order for them to indicate a change in their perception. (c) The mapping of observed probability to the median perceived probability is the identity function over the full range of probabilities. (d) Precision (how close estimates are to the best possible estimate) is good and constant over the full range. (e) Subjects quickly detect substantial changes in the hidden probability parameter. (f) The perceived probability sometimes changes dramatically from one observation to the next. (g) Subjects sometimes have second thoughts about a previous change perception, after observing further outcomes. (h) The frequency with which they perceive changes moves in the direction of the true frequency over sessions. (Explaining this finding requires 2 additional parametric assumptions.) The model treats the perception of the current probability as a by-product of the construction of a compact encoding of the experienced sequence in terms of its change points. It illustrates the why and the how of intermittent Bayesian belief updating and retrospective revision in simple perception. It suggests a reinterpretation of findings in the recent literature on the neurobiology of decision making. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Young Children's Reasoning About Physical & Behavioural Family Resemblance: Is There a Place for a Precursor Model of Inheritance?

NASA Astrophysics Data System (ADS)

Ergazaki, Marida; Alexaki, Aspa; Papadopoulou, Chrysa; Kalpakiori, Marieleni

2014-02-01

This paper aims at exploring (a) whether preschoolers recognize that offspring share physical traits with their parents due to birth and behavioural ones due to nurture, and (b) whether they seem ready to explain shared physical traits with a `pre-biological' causal model that includes the contribution of both parents and a rudimentary notion of genes. This exploration is supposed to provide evidence for our next step, which is the development of an early years' learning environment about inheritance. Conducting individual, semi-structured interviews with 90 preschoolers (age 4.5-5.5) of four public kindergartens in Patras, we attempted to trace their reasoning about (a) whether and why offspring share physical and behavioural traits with parents and (b) which mechanism could better explain the shared physical traits. The probes were a modified six-case version of Solomon et al. (Child Dev 67:151-171, 1996) `adoption task, as well as a three-case task based on Springer's (Child Dev 66:547-558, 1995) `mechanism task' and on Solomon and Johnson's (Br J Dev Psychol 18(1):81-96, 2000) idea of genes as a `conceptual placeholder'. The qualitative and quantitative analysis of the interviews showed overlapping reasoning about the origin of physical and behavioural family resemblance. Nevertheless, we did trace the `birth-driven' argument for the attribution of the offspring's physical traits to the biological parents, as well as a preference for the `pre-biological' model that introduces a rudimentary idea of genes in order to explain shared physical traits between parents and offspring. The findings of the study and the educational implications are thoroughly discussed.

Investigation of the surface potential of TiO2 (110) by frequency-modulation Kelvin probe force microscopy

NASA Astrophysics Data System (ADS)

Kou, Lili; Li, Yan Jun; Kamijyo, Takeshi; Naitoh, Yoshitaka; Sugawara, Yasuhiro

2016-12-01

We investigate the surface potential distribution on a TiO2 (110)-1 × 1 surface by Kelvin probe force microscopy (KPFM) and atom-dependent bias-distance spectroscopic mapping. The experimental results demonstrate that the local contact potential difference increases on twofold-coordinated oxygen sites, and decreases on OH defects and fivefold-coordinated Ti sites. We propose a qualitative model to explain the origin of the surface potential of TiO2 (110). We qualitatively calculate the surface potential induced by chemical potential and permanent surface dipole. The calculated results agree with our experimental ones. Therefore, we suggest that the surface potential of TiO2 (110) is dominated not only by the permanent surface dipole between the tip apex atom and surface, but also by the dipoles induced by the chemical interaction between the tip and sample. The KPFM technique demonstrate the possibility of investigation of the charge transfer phenomenon on TiO2 surface under gas conditions. It is useful for the elucidation of the mechanism of the catalytic reactions.

Investigation of the surface potential of TiO2 (110) by frequency-modulation Kelvin probe force microscopy.

PubMed

Kou, Lili; Li, Yan Jun; Kamijyo, Takeshi; Naitoh, Yoshitaka; Sugawara, Yasuhiro

2016-12-16

We investigate the surface potential distribution on a TiO 2 (110)-1 × 1 surface by Kelvin probe force microscopy (KPFM) and atom-dependent bias-distance spectroscopic mapping. The experimental results demonstrate that the local contact potential difference increases on twofold-coordinated oxygen sites, and decreases on OH defects and fivefold-coordinated Ti sites. We propose a qualitative model to explain the origin of the surface potential of TiO 2 (110). We qualitatively calculate the surface potential induced by chemical potential and permanent surface dipole. The calculated results agree with our experimental ones. Therefore, we suggest that the surface potential of TiO 2 (110) is dominated not only by the permanent surface dipole between the tip apex atom and surface, but also by the dipoles induced by the chemical interaction between the tip and sample. The KPFM technique demonstrate the possibility of investigation of the charge transfer phenomenon on TiO 2 surface under gas conditions. It is useful for the elucidation of the mechanism of the catalytic reactions.

iPhone ECG screening by practice nurses and receptionists for atrial fibrillation in general practice: the GP-SEARCH qualitative pilot study.

PubMed

Orchard, Jessica; Freedman, Saul Benedict; Lowres, Nicole; Peiris, David; Neubeck, Lis

2014-05-01

Atrial fibrillation (AF) is often asymptomatic and substantially increases stroke risk. A single-lead iPhone electrocardiograph (iECG) with a validated AF algorithm could make systematic AF screening feasible in general practice. A qualitative screening pilot study was conducted in three practices. Receptionists and practice nurses screened patients aged ≥65 years using an iECG (transmitted to a secure website) and general practitioner (GP) review was then provided during the patient's consultation. Fourteen semi-structured interviews with GPs, nurses, receptionists and patients were audio-recorded, transcribed and analysed thematically. Eighty-eight patients (51% male; mean age 74.8 ± 8.8 years) were screened: 17 patients (19%) were in AF (all previously diagnosed). The iECG was well accepted by GPs, nurses and patients. Receptionists were reluctant, whereas nurses were confident in using the device, explaining and providing screening. AF screening in general practice is feasible. A promising model is likely to be one delivered by a practice nurse, but depends on relevant contextual factors for each practice.

Qualitative, semi-quantitative, and quantitative simulation of the osmoregulation system in yeast.

PubMed

Pang, Wei; Coghill, George M

2015-05-01

In this paper we demonstrate how Morven, a computational framework which can perform qualitative, semi-quantitative, and quantitative simulation of dynamical systems using the same model formalism, is applied to study the osmotic stress response pathway in yeast. First the Morven framework itself is briefly introduced in terms of the model formalism employed and output format. We then built a qualitative model for the biophysical process of the osmoregulation in yeast, and a global qualitative-level picture was obtained through qualitative simulation of this model. Furthermore, we constructed a Morven model based on existing quantitative model of the osmoregulation system. This model was then simulated qualitatively, semi-quantitatively, and quantitatively. The obtained simulation results are presented with an analysis. Finally the future development of the Morven framework for modelling the dynamic biological systems is discussed. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Development and application of the RE-AIM QuEST mixed methods framework for program evaluation.

PubMed

Forman, Jane; Heisler, Michele; Damschroder, Laura J; Kaselitz, Elizabeth; Kerr, Eve A

2017-06-01

To increase the likelihood of successful implementation of interventions and promote dissemination across real-world settings, it is essential to evaluate outcomes related to dimensions other than Effectiveness alone. Glasgow and colleagues' RE-AIM framework specifies four additional types of outcomes that are important to decision-makers: Reach, Adoption, Implementation (including cost), and Maintenance. To further strengthen RE-AIM, we propose integrating qualitative assessments in an expanded framework: RE-AIM Qualitative Evaluation for Systematic Translation (RE-AIM QuEST), a mixed methods framework. RE-AIM QuEST guides formative evaluation to identify real-time implementation barriers and explain how implementation context may influence translation to additional settings. RE-AIM QuEST was used to evaluate a pharmacist-led hypertension management intervention at 3 VA facilities in 2008-2009. We systematically reviewed each of the five RE-AIM dimensions and created open-ended companion questions to quantitative measures and identified qualitative and quantitative data sources, measures, and analyses. To illustrate use of the RE-AIM QuEST framework, we provide examples of real-time, coordinated use of quantitative process measures and qualitative methods to identify site-specific issues, and retrospective use of these data sources and analyses to understand variation across sites and explain outcomes. For example, in the Reach dimension, we conducted real-time measurement of enrollment across sites and used qualitative data to better understand and address barriers at a low-enrollment site. The RE-AIM QuEST framework may be a useful tool for improving interventions in real-time, for understanding retrospectively why an intervention did or did not work, and for enhancing its sustainability and translation to other settings.

Impurity effect of iron(III) on the growth of potassium sulfate crystal in aqueous solution

NASA Astrophysics Data System (ADS)

Kubota, Noriaki; Katagiri, Ken-ichi; Yokota, Masaaki; Sato, Akira; Yashiro, Hitoshi; Itai, Kazuyoshi

1999-01-01

Growth rates of the {1 1 0} faces of a potassium sulfate crystal were measured in a flow cell in the presence of traces of impurity Fe(III) (up to 2 ppm) over the range of pH=2.5-6.0. The growth rate was significantly suppressed by the impurity. The effect became stronger as the impurity concentration was increased and at pH<5. It became weaker with increasing supersaturation. It also became weaker as the pH was increased and at pH>5 it finally disappeared completely. The concentration and supersaturation effects on the impurity action were reasonably explained with a model proposed by Kubota and Mullin [J. Crystal Growth, 152 (1995) 203]. The surface coverage of the active sites by Fe(III) is estimated to increase linearly on increasing its concentration in solution in the range examined by growth experiments. The impurity effectiveness factor is confirmed to increase inversely proportional to the supersaturation as predicted by the model. Apart from the discussion based on the model, the pH effect on the impurity action is qualitatively explained by assuming that the first hydrolysis product of aqua Fe(III) complex compound, [Fe(H 2O) 5(OH)] 2+, is both growth suppression and adsorption active, but the second hydrolysis product, [Fe(H 2O) 4(OH) 2] +, is only adsorption active.

The Importance Of Integrating Narrative Into Health Care Decision Making.

PubMed

Dohan, Daniel; Garrett, Sarah B; Rendle, Katharine A; Halley, Meghan; Abramson, Corey

2016-04-01

When making health care decisions, patients and consumers use data but also gather stories from family and friends. When advising patients, clinicians consult the medical evidence but also use professional judgment. These stories and judgments, as well as other forms of narrative, shape decision making but remain poorly understood. Furthermore, qualitative research methods to examine narrative are rarely included in health science research. We illustrate how narratives shape decision making and explain why it is difficult but necessary to integrate qualitative research on narrative into the health sciences. We draw on social-scientific insights on rigorous qualitative research and our ongoing studies of decision making by patients with cancer, and we describe new tools and approaches that link qualitative research findings with the predominantly quantitative health science scholarship. Finally, we highlight the benefits of more fully integrating qualitative research and narrative analysis into the medical evidence base and into evidence-based medical practice. Project HOPE—The People-to-People Health Foundation, Inc.

77 FR 24685 - Proposed Information Collection; Comment Request; Client Focus Groups and Qualitative Interviews

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-25

... ask the client to evaluate the U.S. Commercial Service on its customer service provision. Results from... will enrich the quantitative survey data by providing insights and a descriptive context to explain the...

Efferent feedback can explain many hearing phenomena

NASA Astrophysics Data System (ADS)

Holmes, W. Harvey; Flax, Matthew R.

2015-12-01

The mixed mode cochlear amplifier (MMCA) model was presented at the last Mechanics of Hearing workshop [4]. The MMCA consists principally of a nonlinear feedback loop formed when an efferent-controlled outer hair cell (OHC) is combined with the cochlear mechanics and the rest of the relevant neurobiology. Essential elements of this model are efferent control of the OHC motility and a delay in the feedback to the OHC. The input to the MMCA is the passive travelling wave. In the MMCA amplification is localized where both the neural and tuned mechanical systems meet in the Organ of Corti (OoC). The simplest model based on this idea is a nonlinear delay line resonator (DLR), which is mathematically described by a nonlinear delay-differential equation (DDE). This model predicts possible Hopf bifurcations and exhibits its most interesting behaviour when operating near a bifurcation. This contribution presents some simulation results using the DLR model. These show that various observed hearing phenomena can be accounted for by this model, at least qualitatively, including compression effects, two-tone suppression and some forms of otoacoustic emissions (OAEs).

Patterns in the English language: phonological networks, percolation and assembly models

NASA Astrophysics Data System (ADS)

Stella, Massimo; Brede, Markus

2015-05-01

In this paper we provide a quantitative framework for the study of phonological networks (PNs) for the English language by carrying out principled comparisons to null models, either based on site percolation, randomization techniques, or network growth models. In contrast to previous work, we mainly focus on null models that reproduce lower order characteristics of the empirical data. We find that artificial networks matching connectivity properties of the English PN are exceedingly rare: this leads to the hypothesis that the word repertoire might have been assembled over time by preferentially introducing new words which are small modifications of old words. Our null models are able to explain the ‘power-law-like’ part of the degree distributions and generally retrieve qualitative features of the PN such as high clustering, high assortativity coefficient and small-world characteristics. However, the detailed comparison to expectations from null models also points out significant differences, suggesting the presence of additional constraints in word assembly. Key constraints we identify are the avoidance of large degrees, the avoidance of triadic closure and the avoidance of large non-percolating clusters.

How do People Make Sense of Unfamiliar Visualizations?: A Grounded Model of Novice's Information Visualization Sensemaking.

PubMed

Lee, Sukwon; Kim, Sung-Hee; Hung, Ya-Hsin; Lam, Heidi; Kang, Youn-ah; Yi, Ji Soo

2016-01-01

In this paper, we would like to investigate how people make sense of unfamiliar information visualizations. In order to achieve the research goal, we conducted a qualitative study by observing 13 participants when they endeavored to make sense of three unfamiliar visualizations (i.e., a parallel-coordinates plot, a chord diagram, and a treemap) that they encountered for the first time. We collected data including audio/video record of think-aloud sessions and semi-structured interview; and analyzed the data using the grounded theory method. The primary result of this study is a grounded model of NOvice's information Vlsualization Sensemaking (NOVIS model), which consists of the five major cognitive activities: 1 encountering visualization, 2 constructing a frame, 3 exploring visualization, 4 questioning the frame, and 5 floundering on visualization. We introduce the NOVIS model by explaining the five activities with representative quotes from our participants. We also explore the dynamics in the model. Lastly, we compare with other existing models and share further research directions that arose from our observations.

Coping and help in birth: An investigation into 'normal' childbirth as described by new mothers and their attending midwives.

PubMed

Darra, Susanne; Murphy, Fiona

2016-09-01

to investigate how 'normal' childbirth is described by new mothers and their attending midwives. a qualitative, reflexive, narrative study was used to explore birth stories using in-depth, un-structured interviews. 21 new mothers and their 16 attending midwives were recruited from the locality surrounding a district general hospital in South Wales, United Kingdom (UK). the findings identified that the mothers wanted to cope with labour and birth, by breathing through it and using some birth interventions with the help of knowledgeable midwives. Midwives aimed to achieve 'normality' in birth but also commonly utilised birth interventions. Consequently the notion of 'normal' birth as not involving interventions in birth was not found to be a useful defining concept in this study. Furthermore, current dichotomous models and theories of birth and midwifery in particular those relating to pain management did not fully explain the perspectives of these women and their midwives. dichotomous models and theories for birth and midwifery practice and those which incorporate the term 'normal' birth are shown to be not entirely useful to fully explain the contemporary complexity of childbirth in the UK. Therefore it is now necessary to consider avoiding using dichotomous models of birth and midwifery in the UK and to instead concentrate on developing integrated models that reflect the real life current experiences of women and their midwives. Copyright © 2016 Elsevier Ltd. All rights reserved.

Building factorial regression models to explain and predict nitrate concentrations in groundwater under agricultural land

NASA Astrophysics Data System (ADS)

Stigter, T. Y.; Ribeiro, L.; Dill, A. M. M. Carvalho

2008-07-01

SummaryFactorial regression models, based on correspondence analysis, are built to explain the high nitrate concentrations in groundwater beneath an agricultural area in the south of Portugal, exceeding 300 mg/l, as a function of chemical variables, electrical conductivity (EC), land use and hydrogeological setting. Two important advantages of the proposed methodology are that qualitative parameters can be involved in the regression analysis and that multicollinearity is avoided. Regression is performed on eigenvectors extracted from the data similarity matrix, the first of which clearly reveals the impact of agricultural practices and hydrogeological setting on the groundwater chemistry of the study area. Significant correlation exists between response variable NO3- and explanatory variables Ca 2+, Cl -, SO42-, depth to water, aquifer media and land use. Substituting Cl - by the EC results in the most accurate regression model for nitrate, when disregarding the four largest outliers (model A). When built solely on land use and hydrogeological setting, the regression model (model B) is less accurate but more interesting from a practical viewpoint, as it is based on easily obtainable data and can be used to predict nitrate concentrations in groundwater in other areas with similar conditions. This is particularly useful for conservative contaminants, where risk and vulnerability assessment methods, based on assumed rather than established correlations, generally produce erroneous results. Another purpose of the models can be to predict the future evolution of nitrate concentrations under influence of changes in land use or fertilization practices, which occur in compliance with policies such as the Nitrates Directive. Model B predicts a 40% decrease in nitrate concentrations in groundwater of the study area, when horticulture is replaced by other land use with much lower fertilization and irrigation rates.

The Systems Biology Markup Language (SBML) Level 3 Package: Qualitative Models, Version 1, Release 1.

PubMed

Chaouiya, Claudine; Keating, Sarah M; Berenguier, Duncan; Naldi, Aurélien; Thieffry, Denis; van Iersel, Martijn P; Le Novère, Nicolas; Helikar, Tomáš

2015-09-04

Quantitative methods for modelling biological networks require an in-depth knowledge of the biochemical reactions and their stoichiometric and kinetic parameters. In many practical cases, this knowledge is missing. This has led to the development of several qualitative modelling methods using information such as, for example, gene expression data coming from functional genomic experiments. The SBML Level 3 Version 1 Core specification does not provide a mechanism for explicitly encoding qualitative models, but it does provide a mechanism for SBML packages to extend the Core specification and add additional syntactical constructs. The SBML Qualitative Models package for SBML Level 3 adds features so that qualitative models can be directly and explicitly encoded. The approach taken in this package is essentially based on the definition of regulatory or influence graphs. The SBML Qualitative Models package defines the structure and syntax necessary to describe qualitative models that associate discrete levels of activities with entity pools and the transitions between states that describe the processes involved. This is particularly suited to logical models (Boolean or multi-valued) and some classes of Petri net models can be encoded with the approach.

Comparision of alternatively certified and traditionally certified Missouri high school science teachers' perceptions of self-efficacy during the induction period

NASA Astrophysics Data System (ADS)

Gaither, Linda

Sixty percent of America's teachers choose traditional baccalaureate programs while the remaining choose one of several alternative pathways. While certification/training is certainly important to preparing effective teachers, other research indicates that teacher efficacy serves as the foundation of teacher behaviors and classroom practice. The purpose of this study ( N = 94 induction high school science teachers) was to determine the relationships between certification pathway and opportunities to observe modeling; between years of experience and personal teaching efficacy; and teachers' perceptions of what characteristics/ experiences best explain personal teaching efficacy. The Teacher Sense of Efficacy Scale was used in an on-line survey for Phase 1 (n = 91), to measure teacher self-efficacy. In Phase 2, a basic qualitative study was conducted using telephone interviews ( n = 2) and a focus group (n = 4) along with a series of short essay questions from the online survey (n = 91). The findings indicate a significant relationship (p = 0.01) between years of teaching and overall personal teaching-efficacy, student engagement, and instructional strategies; a relationship between opportunities to see modeling and certification pathway, where traditionally certified teachers had significantly more opportunities (p = 0.000); and a relationship between classroom management and opportunities to see modeling (p = 0.005). Qualitative analyses confirmed that traditionally-prepared teachers saw a range of "modeling" and model teachers; respondents related such opportunities to more effective teaching, especially in the realm of classroom management. As more teachers choose alternative certification, it is imperative that adequate opportunities to observe teaching strategies are modeled during the certification process and once teachers enter the classroom; they must have intrinsic and extrinsic support to be successful.

Recurrent competition explains temporal effects of attention in MSTd

PubMed Central

Layton, Oliver W.; Browning, N. Andrew

2012-01-01

Navigation in a static environment along straight paths without eye movements produces radial optic flow fields. A singularity called the focus of expansion (FoE) specifies the direction of travel (heading) of the observer. Cells in primate dorsal medial superior temporal area (MSTd) respond to radial fields and are therefore thought to be heading-sensitive. Humans frequently shift their focus of attention while navigating, for example, depending on the favorable or threatening context of approaching independently moving objects. Recent neurophysiological studies show that the spatial tuning curves of primate MSTd neurons change based on the difference in visual angle between an attentional prime and the FoE. Moreover, the peak mean population activity in MSTd retreats linearly in time as the distance between the attentional prime and FoE increases. We present a dynamical neural circuit model that demonstrates the same linear temporal peak shift observed electrophysiologically. The model qualitatively matches the neuron tuning curves and population activation profiles. After model MT dynamically pools short-range motion, model MSTd incorporates recurrent competition between units tuned to different radial optic flow templates, and integrates attentional signals from model area frontal eye fields (FEF). In the model, population activity peaks occur when the recurrent competition is most active and uncertainty is greatest about the relative position of the FoE. The nature of attention, multiplicative or non-multiplicative, is largely irrelevant, so long as attention has a Gaussian-like profile. Using an appropriately tuned sigmoidal signal function to modulate recurrent feedback affords qualitative fits of deflections in the population activity that otherwise appear to be low-frequency noise. We predict that these deflections mark changes in the balance of attention between the priming and FoE locations. PMID:23060788

Managing lifestyle change to reduce coronary risk: a synthesis of qualitative research on peoples' experiences.

PubMed

Astin, Felicity; Horrocks, Judith; Closs, S Jose

2014-08-05

Coronary heart disease is an incurable condition. The only approach known to slow its progression is healthy lifestyle change and concordance with cardio-protective medicines. Few people fully succeed in these daily activities so potential health improvements are not fully realised. Little is known about peoples' experiences of managing lifestyle change. The aim of this study was to synthesise qualitative research to explain how participants make lifestyle change after a cardiac event and explore this within the wider illness experience. A qualitative synthesis was conducted drawing upon the principles of meta-ethnography. Qualitative studies were identified through a systematic search of 7 databases using explicit criteria. Key concepts were identified and translated across studies. Findings were discussed and diagrammed during a series of audiotaped meetings. The final synthesis is grounded in findings from 27 studies, with over 500 participants (56% male) across 8 countries. All participants experienced a change in their self-identity from what was 'familiar' to 'unfamiliar'. The transition process involved 'finding new limits and a life worth living' , 'finding support for self' and 'finding a new normal'. Analyses of these concepts led to the generation of a third order construct, namely an ongoing process of 'reassessing past, present and future lives' as participants considered their changed identity. Participants experienced a strong urge to get back to 'normal'. Support from family and friends could enable or constrain life change and lifestyle changes. Lifestyle change was but one small part of a wider 'life' change that occurred. The final synthesis presents an interpretation, not evident in the primary studies, of a person-centred model to explain how lifestyle change is situated within 'wider' life changes. The magnitude of individual responses to a changed health status varied. Participants experienced distress as their notion of self identity shifted and emotions that reflected the various stages of the grief process were evident in participants' accounts. The process of self-managing lifestyle took place through experiential learning; the level of engagement with lifestyle change reflected an individual's unique view of the balance needed to manage 'realistic change' whilst leading to a life that was perceived as 'worth living'. Findings highlight the importance of providing person centred care that aligns with both psychological and physical dimensions of recovery which are inextricably linked.

Qualitative model-based diagnosis using possibility theory

NASA Technical Reports Server (NTRS)

Joslyn, Cliff

1994-01-01

The potential for the use of possibility in the qualitative model-based diagnosis of spacecraft systems is described. The first sections of the paper briefly introduce the Model-Based Diagnostic (MBD) approach to spacecraft fault diagnosis; Qualitative Modeling (QM) methodologies; and the concepts of possibilistic modeling in the context of Generalized Information Theory (GIT). Then the necessary conditions for the applicability of possibilistic methods to qualitative MBD, and a number of potential directions for such an application, are described.

It's a sentence, not a word: insights from a keyword analysis in cancer communication.

PubMed

Taylor, Kimberly; Thorne, Sally; Oliffe, John L

2015-01-01

Keyword analysis has been championed as a methodological option for expanding the insights that can be extracted from qualitative datasets using various properties available in qualitative software. Intrigued by the pioneering applications of Clive Seale and his colleagues in this regard, we conducted keyword analyses for word frequency and "keyness" on a qualitative database of interview transcripts from a study on cancer communication. We then subjected the results from these operations to an in-depth contextual inquiry by resituating word instances within their original speech contexts, finding that most of what had initially appeared as group variations broke down under close analysis. In this article, we illustrate the various threads of analysis, and explain how they unraveled under closer scrutiny. On the basis of this tentative exercise, we conclude that a healthy skepticism for the benefits of keyword analysis within a qualitative investigative process seems warranted. © The Author(s) 2014.

Stravinsky's "Firebird" and Young Children.

ERIC Educational Resources Information Center

Roebuck, Edith

1999-01-01

Describes how the young children of the Early Learning Center in the Chelsea (Massachusetts) school district learned about Igor Stravinsky's ballet suite, "The Firebird." Explains that children in three kindergarten classes depicted the ballet's characters in a participatory performance. Highlights some qualitative observations. (CMK)

Analysis of polarized-light effects in glass-promoting solutions with applications to cryopreservation and organ banking.

PubMed

Solanki, Prem K; Rabin, Yoed

2018-01-01

This study presents experimental results and an analysis approach for polarized light effects associated with thermomechanical stress during cooling of glass promoting solutions, with applications to cryopreservation and tissue banking in a process known as vitrification. Polarized light means have been previously integrated into the cryomacroscope-a visualization device to detect physical effects associated with cryopreservation success, such as crystallization, fracture formation, and contamination. The experimental study concerns vitrification in a cuvette, which is a rectangular container. Polarized light modeling in the cuvette is based on subdividing the tridimensional (3D) domain into a series of planar (2D) problems, for which a mathematical solution is available in the literature. The current analysis is based on tracking the accumulated changes in light polarization and magnitude, as it passes through the sequence of planar problems. Results of this study show qualitative agreement in light intensity history and distribution between experimental data and simulated results. The simulated results help explaining differences between 2D and 3D effects in photoelasticity, most notably, the counterintuitive observation that high stress areas may correlate with low light intensity regions based on the particular experimental conditions. Finally, it is suggested that polarized-light analysis must always be accompanied by thermomechanical stress modeling in order to explain 3D effects.

Alignment of cellular motility forces with tissue flow as a mechanism for efficient wound healing

PubMed Central

Basan, Markus; Elgeti, Jens; Hannezo, Edouard; Rappel, Wouter-Jan; Levine, Herbert

2013-01-01

Recent experiments have shown that spreading epithelial sheets exhibit a long-range coordination of motility forces that leads to a buildup of tension in the tissue, which may enhance cell division and the speed of wound healing. Furthermore, the edges of these epithelial sheets commonly show finger-like protrusions whereas the bulk often displays spontaneous swirls of motile cells. To explain these experimental observations, we propose a simple flocking-type mechanism, in which cells tend to align their motility forces with their velocity. Implementing this idea in a mechanical tissue simulation, the proposed model gives rise to efficient spreading and can explain the experimentally observed long-range alignment of motility forces in highly disordered patterns, as well as the buildup of tensile stress throughout the tissue. Our model also qualitatively reproduces the dependence of swirl size and swirl velocity on cell density reported in experiments and exhibits an undulation instability at the edge of the spreading tissue commonly observed in vivo. Finally, we study the dependence of colony spreading speed on important physical and biological parameters and derive simple scaling relations that show that coordination of motility forces leads to an improvement of the wound healing process for realistic tissue parameters. PMID:23345440

Analysis of polarized-light effects in glass-promoting solutions with applications to cryopreservation and organ banking

PubMed Central

2018-01-01

This study presents experimental results and an analysis approach for polarized light effects associated with thermomechanical stress during cooling of glass promoting solutions, with applications to cryopreservation and tissue banking in a process known as vitrification. Polarized light means have been previously integrated into the cryomacroscope—a visualization device to detect physical effects associated with cryopreservation success, such as crystallization, fracture formation, and contamination. The experimental study concerns vitrification in a cuvette, which is a rectangular container. Polarized light modeling in the cuvette is based on subdividing the tridimensional (3D) domain into a series of planar (2D) problems, for which a mathematical solution is available in the literature. The current analysis is based on tracking the accumulated changes in light polarization and magnitude, as it passes through the sequence of planar problems. Results of this study show qualitative agreement in light intensity history and distribution between experimental data and simulated results. The simulated results help explaining differences between 2D and 3D effects in photoelasticity, most notably, the counterintuitive observation that high stress areas may correlate with low light intensity regions based on the particular experimental conditions. Finally, it is suggested that polarized-light analysis must always be accompanied by thermomechanical stress modeling in order to explain 3D effects. PMID:29912973

Characterizing steady states of genome-scale metabolic networks in continuous cell cultures.

PubMed

Fernandez-de-Cossio-Diaz, Jorge; Leon, Kalet; Mulet, Roberto

2017-11-01

In the continuous mode of cell culture, a constant flow carrying fresh media replaces culture fluid, cells, nutrients and secreted metabolites. Here we present a model for continuous cell culture coupling intra-cellular metabolism to extracellular variables describing the state of the bioreactor, taking into account the growth capacity of the cell and the impact of toxic byproduct accumulation. We provide a method to determine the steady states of this system that is tractable for metabolic networks of arbitrary complexity. We demonstrate our approach in a toy model first, and then in a genome-scale metabolic network of the Chinese hamster ovary cell line, obtaining results that are in qualitative agreement with experimental observations. We derive a number of consequences from the model that are independent of parameter values. The ratio between cell density and dilution rate is an ideal control parameter to fix a steady state with desired metabolic properties. This conclusion is robust even in the presence of multi-stability, which is explained in our model by a negative feedback loop due to toxic byproduct accumulation. A complex landscape of steady states emerges from our simulations, including multiple metabolic switches, which also explain why cell-line and media benchmarks carried out in batch culture cannot be extrapolated to perfusion. On the other hand, we predict invariance laws between continuous cell cultures with different parameters. A practical consequence is that the chemostat is an ideal experimental model for large-scale high-density perfusion cultures, where the complex landscape of metabolic transitions is faithfully reproduced.

Characterizing steady states of genome-scale metabolic networks in continuous cell cultures

PubMed Central

Leon, Kalet; Mulet, Roberto

2017-01-01

In the continuous mode of cell culture, a constant flow carrying fresh media replaces culture fluid, cells, nutrients and secreted metabolites. Here we present a model for continuous cell culture coupling intra-cellular metabolism to extracellular variables describing the state of the bioreactor, taking into account the growth capacity of the cell and the impact of toxic byproduct accumulation. We provide a method to determine the steady states of this system that is tractable for metabolic networks of arbitrary complexity. We demonstrate our approach in a toy model first, and then in a genome-scale metabolic network of the Chinese hamster ovary cell line, obtaining results that are in qualitative agreement with experimental observations. We derive a number of consequences from the model that are independent of parameter values. The ratio between cell density and dilution rate is an ideal control parameter to fix a steady state with desired metabolic properties. This conclusion is robust even in the presence of multi-stability, which is explained in our model by a negative feedback loop due to toxic byproduct accumulation. A complex landscape of steady states emerges from our simulations, including multiple metabolic switches, which also explain why cell-line and media benchmarks carried out in batch culture cannot be extrapolated to perfusion. On the other hand, we predict invariance laws between continuous cell cultures with different parameters. A practical consequence is that the chemostat is an ideal experimental model for large-scale high-density perfusion cultures, where the complex landscape of metabolic transitions is faithfully reproduced. PMID:29131817

Color-Word Stroop test performance across the adult life span.

PubMed

Uttl, B; Graf, P

1997-06-01

In the Color-Word Stroop test (CWST), the basic task is to name the ink color of rows of XXXs, and performance in this condition is compared with performance in naming the ink-color of color words under conditions where word meanings and ink colors mismatch or are incongruent (e.g., the word red printed in green ink). The present study investigated whether Stroop test interference, defined as the cost associated with ink-color naming in the incongruous stimulus condition versus in the basic color-naming condition, provides positive evidence for a kind of processing qualitatively different than that which is required for color naming or for word reading. Does the pattern of age-related differences in Stroop interference force the conclusion that the incongruous condition taps a qualitatively different kind of processing than that required for color naming or for word reading? We gave the CWST to 310 healthy adults. Their performance in each condition of the test replicates and extends previous findings. Structural equation modeling of the data showed a significant, direct link between age and performance in the latent factor associated with the incongruent condition. However, this direct link with age produced a relatively small increase in the model's fit; it amounted to only a .024 increase in the proportion of variance explained in the incongruent condition. In light of this small direct influence due to age, the most parsimonious explanation of our findings is that age effects in Stroop interference are due to age-related slowing (which is also indexed by color naming and by word reading) primarily; the findings do not provide evidence for a qualitatively different kind of processing that declines with age.

Beyond Corroboration: Strengthening Model Validation by Looking for Unexpected Patterns

PubMed Central

Chérel, Guillaume; Cottineau, Clémentine; Reuillon, Romain

2015-01-01

Models of emergent phenomena are designed to provide an explanation to global-scale phenomena from local-scale processes. Model validation is commonly done by verifying that the model is able to reproduce the patterns to be explained. We argue that robust validation must not only be based on corroboration, but also on attempting to falsify the model, i.e. making sure that the model behaves soundly for any reasonable input and parameter values. We propose an open-ended evolutionary method based on Novelty Search to look for the diverse patterns a model can produce. The Pattern Space Exploration method was tested on a model of collective motion and compared to three common a priori sampling experiment designs. The method successfully discovered all known qualitatively different kinds of collective motion, and performed much better than the a priori sampling methods. The method was then applied to a case study of city system dynamics to explore the model’s predicted values of city hierarchisation and population growth. This case study showed that the method can provide insights on potential predictive scenarios as well as falsifiers of the model when the simulated dynamics are highly unrealistic. PMID:26368917

Diffuse scattering in relaxor ferroelectrics: true three-dimensional mapping, experimental artefacts and modelling.

PubMed

Bosak, A; Chernyshov, D; Vakhrushev, Sergey; Krisch, M

2012-01-01

The available body of experimental data in terms of the relaxor-specific component of diffuse scattering is critically analysed and a collection of related models is reviewed; the sources of experimental artefacts and consequent failures of modelling efforts are enumerated. Furthermore, it is shown that the widely used concept of polar nanoregions as individual static entities is incompatible with the experimental diffuse scattering results. Based on the synchrotron diffuse scattering three-dimensional data set taken for the prototypical ferroelectric relaxor lead magnesium niobate-lead titanate (PMN-PT), a new parameterization of diffuse scattering in relaxors is presented and a simple phenomenological picture is proposed to explain the unusual properties of the relaxor behaviour. The model assumes a specific slowly changing displacement pattern, which is indirectly controlled by the low-energy acoustic phonons of the system. The model provides a qualitative but rather detailed explanation of temperature, pressure and electric-field dependence of diffuse neutron and X-ray scattering, as well as of the existence of a hierarchy in the relaxation times of these materials.

Spin-dependence of the electron scattering cross section by a magnetic layer system and the magneto-resistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, J.T.; Tang, F.; Brown, W.D.

1998-12-20

The authors present a theoretical model for calculating the spin-dependent cross section of the scattering of electrons by a magnetic layer system. The model demonstrates that the cross sections of the scattering are different for spin up and spin down electrons. The model assumes that the electrical resistivity in a conductor is proportional to the scattering cross section of the electron in it. It is believed to support the two channel mechanism in interpreting magneto-resistance (MR). Based on the model without considering the scattering due to the interfacial roughness and the spin flipping scattering, the authors have established a relationshipmore » between MR and the square of the magnetic moment in the bulk sample without considering the scattering due to the interfacial roughness and the spin flipping scattering. It can also qualitatively explain the MR difference between the current in plane (CIP) and current perpendicular to the plane (CPP) configurations. The predictions by the model agree well with the experimental findings.« less

[Adherence as a result of a "particular relationship". HIV-infected patients about their physician-patient relationship].

PubMed

Engelbach, Ute; Dannecker, Martin; Kaufhold, Johannes; Lenz, Cynthia; Grabhorn, Ralph

2008-06-01

This qualitative study examines the relationship between doctors and HIV-infected patients with regard to problems of adherence. Objective hermeneutics was used to analyze the scene of a doctor-patient conversation produced through psychodrama. Specific traits shared by the patients in question were a confused regulation of closeness and distance as well as a non-maintenance of the traditional asymmetry within the doctor-patient relation. The patients faced the doctors on a level of diffuse social relations and showed the tendency to involve the doctor into their community. The conclusion for a model explaining patients' adherence may be: it exist an individual level of the need for being accepted by the doctor as somebody particular. If this level is reached, i. e. individual claims are met and personal desires are satisfied, the patient will follow the physician's advice. Authors discuss whether the model is compatible with the conflict of self-esteem.

A direct evidence of allocating yellow luminescence band in undoped GaN by two-wavelength excited photoluminescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Julkarnain, M., E-mail: s13ds053@mail.saitama-u.ac.jp, E-mail: jnain.apee@ru.ac.bd; Department of Applied Physics and Electronic Engineering, University of Rajshahi, Rajshahi 6205; Fukuda, T.

2015-11-23

The behavior of below-gap luminescence of undoped GaN grown by MOCVD has been studied by the scheme of two-wavelength-excited photoluminescence. The emission intensity of shallow donor to valence band transition (I{sub OX}) increased while intensities of donor-acceptor pair transition and the Yellow Luminescence band (YLB) decreased after the irradiation of a below-gap excitation source of 1.17 eV. The conventional energy schemes and recombination models have been considered to explain our experimental result but only one model in which YLB is the transition of a shallow donor to a deep state placed at ∼1 eV above the valence band maximum satisfies our result.more » The defect related parameters that give a qualitative insight in the samples have been evaluated by systematically solving the rate equations and fitting the result with the experiment.« less

Body-Mind Healing Strategies in Patients with Cancer: a Qualitative Content Analysis

PubMed

Khoshnood, Zohreh; Iranmanesh, Sedigheh; Rayyani, Masoud; Dehghan, Mahlegha

2018-06-25

Background: Cancer is a major health problem around the world. The use of coping strategies among patients with cancer depends on several issues. This study was conducted to determine coping strategies used by patients with cancer in south-east Iran. Methods: This study is a conventional, qualitative content analysis with a descriptive explorative approach. Data saturation achieved after interviewing 13 participants in 15 interviews. Using an in-depth individual semi-structured approach the participants were asked to narrate their experiences of strategies that they used to cope with cancer. The following were considered: unit of analysis, meaning unit, condensation, code, sub-category, category, and main category. Results: Data analysis led to extraction of two main categories of body-mind healing strategies: being connected to the body and mindfully reconnected to the self. The first category was explained with reference to two sub-categories, being aware of intelligence and body nurturing. The second category was explained with the three sub-categories of using embodying knowledge, living for the moment, and being connected to nature. Conclusion: According to the results of this qualitative study, it is possible to form discussion groups with peers or to have self-reflective practice learning groups to reflect patients’ questions and strategies that they use for body-mind healing. Creative Commons Attribution License

Computer Aided Teaching of Digital Signal Processing.

ERIC Educational Resources Information Center

Castro, Ian P.

1990-01-01

Describes a microcomputer-based software package developed at the University of Surrey for teaching digital signal processing to undergraduate science and engineering students. Menu-driven software capabilities are explained, including demonstration of qualitative concepts and experimentation with quantitative data, and examples are given of…

The Lenz Vector and Orbital Analog Computers

ERIC Educational Resources Information Center

Harter, W. G.

1976-01-01

Describes a single geometrical diagram based on the Lenz vector which shows the qualitative and quantitative features of all three types of Coulomb orbits. Explains the use of a simple analog computer with an overhead projector to demonstrate many of these effects. (Author/CP)

Charge Transfer Exciton in Halogen-Bridged Mixed-Valent Pt and Pd Complexes: Analysis Based on the Peierls-Hubbard Model

NASA Astrophysics Data System (ADS)

Wada, Yoshiki; Mitani, Tadaoki; Yamashita, Masahiro; Koda, Takao

1985-08-01

Polarized reflection and luminescence have been measured for the single crystals of [MA2][MX2A2](ClO4)4 (M=Pt, Pd, X=Cl, Br, I and A=ethylenediamine, cyclohexanediamine). The strong absorption bands due to the charge-transfer (CT) exciton transitions between the mixed-valent metal ions have been investigated in detail in the visible or infrared energy regions. The dependence of the CT excitation energies on the species M and X is shown to be consistent with the prediction by the Peierls-Hubbard model which incorporates the effect of the electron-electron correlation on inter-metal sites. The oscillator strength of the CT excitons are observed to be enhanced by substituting heavier halogen ions. This enhancement is interpreted by a halogen-linked super-transfer mechanism. The unusually large values of the oscillator strength can be qualitatively explained in terms of the trimer CT model.

Influence of thermal annealing on the bulk scattering in giant-magnetoresistance spin-valve with nano-oxide layers

NASA Astrophysics Data System (ADS)

Nam, Chunghee; Jang, Youngman; Lee, Ki-Su; Shim, Jungjin; Cho, B. K.

2006-04-01

Based upon a bulk scattering model, we investigated the variation of giant magnetoresistance (GMR) behavior after thermal annealing at Ta=250 °C as a function of the top free layer thickness of a GMR spin valve with nano-oxide layers (NOLs). It was found that the enhancement of GMR ratio after thermal annealing is explained qualitatively in terms of the increase of active GMR region in the free layer and, simultaneously, the increase of intrinsic spin-scattering ratio. These effects are likely due to the improved specular reflection at the well-formed interface of NOL. Furthermore, we developed a modified phenomenological model for sheet conductance change (ΔG) in terms of the top free layer thickness. This modified model was found to be useful in the quantitative analysis of the variation of the active GMR region and the intrinsic spin-scattering properties. The two physical parameters were found to change consistently with the effects of thermal annealing on NOL.

Experiments and theory of undulatory locomotion in a simple structured medium

PubMed Central

Majmudar, Trushant; Keaveny, Eric E.; Zhang, Jun; Shelley, Michael J.

2012-01-01

Undulatory locomotion of micro-organisms through geometrically complex, fluidic environments is ubiquitous in nature and requires the organism to negotiate both hydrodynamic effects and geometrical constraints. To understand locomotion through such media, we experimentally investigate swimming of the nematode Caenorhabditis elegans through fluid-filled arrays of micro-pillars and conduct numerical simulations based on a mechanical model of the worm that incorporates hydrodynamic and contact interactions with the lattice. We show that the nematode's path, speed and gait are significantly altered by the presence of the obstacles and depend strongly on lattice spacing. These changes and their dependence on lattice spacing are captured, both qualitatively and quantitatively, by our purely mechanical model. Using the model, we demonstrate that purely mechanical interactions between the swimmer and obstacles can produce complex trajectories, gait changes and velocity fluctuations, yielding some of the life-like dynamics exhibited by the real nematode. Our results show that mechanics, rather than biological sensing and behaviour, can explain some of the observed changes in the worm's locomotory dynamics. PMID:22319110

Meeting Health and Psychological Needs of Women In Drug Treatment Court

PubMed Central

Morse, Diane S.; Cerulli, Catherine; Bedell, Precious; Wilson, John L.; Thomas, Katherine; Mittal, Mona; Lamberti, J. Steven; Williams, Geoffrey; Silverstein, Jennifer; Mukherjee, Aninda; Walck, Donna; Chin, Nancy

2013-01-01

We explored healthcare-related experiences of women drug court participants through combining context from the Socio-Ecological Model with motivation needs for health behavior as indicated by self-determination theory. Five focus groups with 8 women drug court participants, 8 court staff, and 9 community service providers were examined using qualitative framework analysis. Themes emerged across the Socio-Ecological Model and were cross-mapped with self-determination theory-defined motivation needs for autonomy, relatedness, and competence. Socio-Ecological levels contained experiences either supporting or eroding women’s motivation needs: 1) intrapersonal challenges participants termed an “evil cycle” of relapse, recidivism, trauma, and life challenges; 2) interpersonal context of parenting and stigma involving features of this “evil cycle”; 3) institutions with logistical barriers to legal and medical assistance; 4) community resources inadequate to support living and employment needs. Self-determination theory helps explain motivation required to address the women’s healthcare needs and multiple demands at all levels of the Socio-Ecological Model. PMID:24074850

Meeting health and psychological needs of women in drug treatment court.

PubMed

Morse, Diane S; Cerulli, Catherine; Bedell, Precious; Wilson, John L; Thomas, Katherine; Mittal, Mona; Lamberti, J Steven; Williams, Geoffrey; Silverstein, Jennifer; Mukherjee, Aninda; Walck, Donna; Chin, Nancy

2014-02-01

We explored healthcare-related experiences of women drug court participants through combining context from the socio-ecological model with motivation needs for health behavior as indicated by self-determination theory. Five focus groups with 8 women drug court participants, 8 court staff, and 9 community service providers were examined using qualitative framework analysis. Themes emerged across the socio-ecological model and were cross-mapped with self-determination theory-defined motivation needs for autonomy, relatedness, and competence. Socio-ecological levels contained experiences either supporting or eroding women's motivation needs: (1) intrapersonal challenges participants termed an "evil cycle" of relapse, recidivism, trauma, and life challenges; (2) interpersonal context of parenting and stigma involving features of this "evil cycle"; (3) institutions with logistical barriers to legal and medical assistance; (4) community resources inadequate to support living and employment needs. Self-determination theory helps explain motivation required to address the women's healthcare needs and multiple demands at all levels of the socio-ecological model. © 2013.

Cooperative binding of drugs on human serum albumin

NASA Astrophysics Data System (ADS)

Varela, L. M.; Pérez-Rodríguez, M.; García, M.

In order to explain the adsorption isotherms of the amphiphilic penicillins nafcillin and cloxacillin onto human serum albumin (HSA), a cooperative multilayer adsorption model is introduced, combining the Brunauer-Emmet-Teller (BET) adsorption isotherm with an amphiphilic ionic adsorbate, whose chemical potential is derived from Guggenheim's theory. The non-cooperative model has been previously proved to qualitatively predict the measured adsorption maxima of these drugs [Varela, L. M., García, M., Pérez-Rodríguez, M., Taboada, P., Ruso, J. M., and Mosquera, V., 2001, J. chem. Phys., 114, 7682]. The surface interactions among adsorbed drug molecules are modelled in a mean-field fashion, so the chemical potential of the adsorbate is assumed to include a term proportional to the surface coverage, the constant of proportionality being the lateral interaction energy between bound molecules. The interaction energies obtained from the empirical binding isotherms are of the order of tenths of the thermal energy, therefore suggesting the principal role of van der Waals forces in the binding process.

A study of the electric field in an open magnetospheric model

NASA Technical Reports Server (NTRS)

Stern, D. P.

1972-01-01

The qualitative properties of an open magnetosphere and its electric field are examined and compared to a simple model of a dipole in a constant field and to actual observations. Many of these properties are found to depend on the separatrix, a curve connecting neutral points and separating different field-line regimes. In the simple model, the electric field in the central polar cap tends to point from dawn to dusk for a wide choice of external fields. Near the boundary of the polar cap electric equipotentials curve and become crescent-shaped, which may explain the correlation of polar magnetic variations with the azimuthal component of the interplanetary magnetic field, reported by Svalgaard. Modifications expected to occur in the actual magnetosphere are also investigated: in particular, it appears that bending of equipotentials may be reduced by cross-field flow during the merging of field lines and that open field lines connected to the polar caps emerge from a long and narrow slot extending along the tail.

Sense of coherence and hardiness as predictors of the mental health of college students.

PubMed

Knowlden, Adam P; Sharma, Manoj; Kanekar, Amar; Atri, Ashutosh

Psychological distress has a deleterious impact on the mental health of college students. The purpose of this study was to specify a theoretical, sense of coherence, and hardiness-based regression model to predict the mental health of college students. The instruments employed to build the model included the Kessler Psychological Distress Scale K-6, the Sense of Coherence-29, and the College Student Hardiness Measure. Data were collected from a sample of college students (n = 220) attending a Midwestern university. Each of the theoretical predictors regressed on mental health was deemed significant. Collectively, the significant predictors produced an R2 adjusted value of 0.434 (p < 0.001), suggesting the final specified model explained 43.4% of the variance in mental health in the sample of participants. Qualitative cut-points were developed for each scale to aid in measurement of health promotion and education interventions designed to improve the mental health of college students.

Giant plasmon excitation in single and double ionization of C60 by fast highly charged Si and O ions

NASA Astrophysics Data System (ADS)

Kelkar, A. H.; Kadhane, U.; Misra, D.; Tribedi, L. C.

2007-09-01

Se have investigated single and double ionization of C60 molecule in collisions with 2.33 MeV/u Siq+ (q=6-14) and 3.125 MeV/u Oq+ (q=5-8) projectiles. The projectile charge state dependence of the single and double ionization yields of C60 are then compared to those for an ion-atom collision system using Ne gas as a target. A large difference between the gas and the cluster target behaviour was partially explained in terms of a model based on collective excitation namely the giant dipole plasmon resonance (GDPR). The qualitative agreement between the data and GDPR model prediction for single and double ionization signifies the importance of single and double plasmon excitations in the ionization process. A large deviation of the GDPR model for triple and quadruple ionization from the experimental data imply the importance of the other low impact parameter processes such as evaporation, fragmentation and a possible solid-like dynamical screening.

Dynamics and spatio-temporal variability of environmental factors in Eastern Australia using functional principal component analysis

USGS Publications Warehouse

Szabo, J.K.; Fedriani, E.M.; Segovia-Gonzalez, M. M.; Astheimer, L.B.; Hooper, M.J.

2010-01-01

This paper introduces a new technique in ecology to analyze spatial and temporal variability in environmental variables. By using simple statistics, we explore the relations between abiotic and biotic variables that influence animal distributions. However, spatial and temporal variability in rainfall, a key variable in ecological studies, can cause difficulties to any basic model including time evolution. The study was of a landscape scale (three million square kilometers in eastern Australia), mainly over the period of 19982004. We simultaneously considered qualitative spatial (soil and habitat types) and quantitative temporal (rainfall) variables in a Geographical Information System environment. In addition to some techniques commonly used in ecology, we applied a new method, Functional Principal Component Analysis, which proved to be very suitable for this case, as it explained more than 97% of the total variance of the rainfall data, providing us with substitute variables that are easier to manage and are even able to explain rainfall patterns. The main variable came from a habitat classification that showed strong correlations with rainfall values and soil types. ?? 2010 World Scientific Publishing Company.

History dependent crystallization of Zr41Ti14Cu12Ni10Be23 melts

NASA Astrophysics Data System (ADS)

Schroers, Jan; Johnson, William L.

2000-07-01

The crystallization of Zr41Ti14Cu12Ni10Be23 (Vit 1) melts during constant heating is investigated. (Vit 1) melts are cooled with different rates into the amorphous state and the crystallization temperature upon subsequent heating is studied. In addition, Vit 1 melts are cooled using a constant rate to different temperatures and subsequently heated from this temperature with a constant rate. We investigate the influence of the temperature to which the melt was cooled on the crystallization temperature measured upon heating. In both cases the onset temperature of crystallization shows strong history dependence. This can be explained by an accumulating process during cooling and heating. An attempt is made to consider this process in a simple model by steady state nucleation and subsequent growth of the nuclei which results in different crystallization kinetics during cooling or heating. Calculations show qualitative agreement with the experimental results. However, calculated and experimental results differ quantitatively. This difference can be explained by a decomposition process leading to a nonsteady nucleation rate which continuously increases with decreasing temperature.

Qualitative mathematical models to support ecosystem-based management of Australia's Northern Prawn Fishery.

PubMed

Dambacher, Jeffrey M; Rothlisberg, Peter C; Loneragan, Neil R

2015-01-01

A major decline in the catch of the banana prawn [shrimp], Penaeus (Fenneropenaeus) merguiensis, occurred over a six-year period in the Weipa region of the northeastern Gulf of Carpentaria, Australia. Three main hypotheses have been developed to explain this decline: (1) prawn recruitment collapsed due to overfishing; (2) recruitment collapsed due to a change in the prawn's environment; and (3) adult banana prawns were still present, but fishers could no longer effectively find or catch them. Qualitative mathematical models were used to link population biology, environmental factors, and fishery dynamics to evaluate the alternative hypotheses. This modeling approach provides the means to rapidly integrate knowledge across disciplines and consider alternative hypotheses about how the structure and function of an ecosystem affects its dynamics. Alternative models were constructed to address the different hypotheses and also to encompass a diversity of opinion about the underlying dynamics of the system. Key findings from these analyses are that: instability in the system can arise when discarded fishery bycatch supports relatively high predation pressure; system stability can be enhanced by management of fishing effort or stock catchability; catch per unit effort is not necessarily a reliable indicator of stock abundance; a change in early-season rainfall should affect all stages in the banana prawn's life cycle; and a reduced catch in the Weipa region can create and reinforce a shift in fishing effort away from Weipa. Results from the models informed an approach to test the hypotheses (i.e., an experimental fishing program), and promoted understanding of the system among researchers, management agencies, and industry. The analytical tools developed in this work to address stages of a prawn life cycle and fishery dynamics are generally applicable to any exploited natural. resource.

Testing mechanistic models of growth in insects.

PubMed

Maino, James L; Kearney, Michael R

2015-11-22

Insects are typified by their small size, large numbers, impressive reproductive output and rapid growth. However, insect growth is not simply rapid; rather, insects follow a qualitatively distinct trajectory to many other animals. Here we present a mechanistic growth model for insects and show that increasing specific assimilation during the growth phase can explain the near-exponential growth trajectory of insects. The presented model is tested against growth data on 50 insects, and compared against other mechanistic growth models. Unlike the other mechanistic models, our growth model predicts energy reserves per biomass to increase with age, which implies a higher production efficiency and energy density of biomass in later instars. These predictions are tested against data compiled from the literature whereby it is confirmed that insects increase their production efficiency (by 24 percentage points) and energy density (by 4 J mg(-1)) between hatching and the attainment of full size. The model suggests that insects achieve greater production efficiencies and enhanced growth rates by increasing specific assimilation and increasing energy reserves per biomass, which are less costly to maintain than structural biomass. Our findings illustrate how the explanatory and predictive power of mechanistic growth models comes from their grounding in underlying biological processes. © 2015 The Author(s).

Explain the 'unexplainable': A qualitative enquiry of the representations of the caregivers of brain-injured people.

PubMed

Huet, Magali; Dany, Lionel; Apostolidis, Thémistoklis

2016-04-01

The aim of our research is to highlight the role of social representations of the traumatic brain-injured person in the adjustments made by caregivers in building and maintaining quality of care. Twenty-three semi-structured interviews were conducted with nursing assistants and medico-psychological assistants, working in a long-term care facility. The interviews were the subject of a thematic content analysis. The analysis shows the role of representations of the traumatic brain-injured person in the way caregivers explain behaviours and situations and in the orientation of their professional practices. In explaining the inexplicable, caregivers establish a more human relationship through individualized care.

Dynamics of the evaporative dewetting of a volatile liquid film confined within a circular ring.

PubMed

Sun, Wei; Yang, Fuqian

2015-04-07

The dewetting dynamics of a toluene film confined within a copper ring on a deformable PMMA film is studied. The toluene film experiences evaporation and dewetting, which leads to the formation of a circular contact line around the center of the copper ring. The contact line recedes smoothly toward the copper ring at a constant velocity until reaching a dynamic "stick" state to form the first circular polymer ridge. The average receding velocity is found to be dependent on the dimensions of the copper ring (the copper ring diameter and the cross-sectional diameter of the copper wire) and the thickness of the PMMA films. A model is presented to qualitatively explain the evaporative dewetting phenomenon.

Pleasure, Power, and Inequality: Incorporating Sexuality Into Research on Contraceptive Use

PubMed Central

Hirsch, Jennifer S.

2008-01-01

We know surprisingly little about how contraception affects sexual enjoyment and functioning (and vice versa), particularly for women. What do people seek from sex, and how do sexual experiences shape contraceptive use? We draw on qualitative data to make 3 points. First, pleasure varies. Both women and men reported multiple aspects of enjoyment, of which physical pleasure was only one. Second, pleasure matters. Clear links exist between the forms of pleasure respondents seek and their contraceptive practices. Third, pleasure intersects with power and social inequality. Both gender and social class shape sexual preferences and contraceptive use patterns. These findings call for a reframing of behavioral models that explain why people use (or do not use) contraception. PMID:18703457

[Chronic low back pain: from the uncertain medical diagnosis to the profane etiologies].

PubMed

Mbarga, Josiane; Pichonnaz, Claude; Foley, Rose-Anna; Ancey, Céline

2018-04-18

This qualitative research article is based on interviews with 20 participants to a low back pain rehabilitation program in a Swiss hospital. It shows that, in the absence of the obvious cause that can explain pain, patients construct their own interpretations and explanations in order to give meaning to their experience. Their explanatory models mainly include the lifestyle and the physical aspects related to the body function, what leaves little room for the psychosocial component. Their interpretation is consequently discordant with the current medical approach, which considers that chronic low back pain results from bio-psycho-social factors. This discrepancy implies negotiation between patients and professionals about the objectives to achieve in order to treat pain.

Multinomial Bayesian learning for modeling classical and nonclassical receptive field properties.

PubMed

Hosoya, Haruo

2012-08-01

We study the interplay of Bayesian inference and natural image learning in a hierarchical vision system, in relation to the response properties of early visual cortex. We particularly focus on a Bayesian network with multinomial variables that can represent discrete feature spaces similar to hypercolumns combining minicolumns, enforce sparsity of activation to learn efficient representations, and explain divisive normalization. We demonstrate that maximal-likelihood learning using sampling-based Bayesian inference gives rise to classical receptive field properties similar to V1 simple cells and V2 cells, while inference performed on the trained network yields nonclassical context-dependent response properties such as cross-orientation suppression and filling in. Comparison with known physiological properties reveals some qualitative and quantitative similarities.

Self-consistent formation of electron $\\kappa$ distribution: 1. Theory

NASA Astrophysics Data System (ADS)

Yoon, Peter H.; Rhee, Tongnyeol; Ryu, Chang-Mo

2006-09-01

Since the early days of plasma physics research suprathermal electrons were observed to be generated during beam-plasma laboratory experiments. Energetic electrons, often modeled by κ distributions, are also ubiquitously observed in space. Various particle acceleration mechanisms have been proposed to explain such a feature, but all previous theories rely on either qualitative analytical method or on non-self-consistent approaches. This paper discusses the self-consistent acceleration of electrons to suprathermal energies by weak turbulence processes which involve the Langmuir/ion-sound turbulence and the beam-plasma interaction. It is discussed that the spontaneous scatttering process, which is absent in the purely collisionless theory, is singularly responsible for the generation of κ distributions. The conclusion is that purely collisionless Vlasov theory cannot produce suprathermal population.

Rapidity dependence in holographic heavy ion collisions

DOE PAGES

Wilke van der Schee; Schenke, Bjorn

2015-12-11

We present an attempt to closely mimic the initial stage of heavy ion collisions within holography, assuming a decoupling of longitudinal and transverse dynamics in the very early stage. We subsequently evolve the obtained initial state using state-of-the-art hydrodynamic simulations and compare results with experimental data. We present results for charged hadron pseudorapidity spectra and directed and elliptic flow as functions of pseudorapidity for √s NN = 200GeV Au-Au and 2.76TeV Pb-Pb collisions. As a result, the directed flow interestingly turns out to be quite sensitive to the viscosity. The results can explain qualitative features of the collisions, but themore » rapidity spectra in our current model is narrower than the experimental data.« less

A NON-PRE DOUBLE-PEAKED BURST FROM 4U 1636-536: EVIDENCE FOR BURNING FRONT PROPAGATION

NASA Technical Reports Server (NTRS)

Bhattacharyya, Sudip; Strohmayer, Tod E.

2005-01-01

We analyse Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) data of a double-peaked burst from the low mass X-ray binary (LMXB) 4U 1636-536 that shows no evidence for photospheric radius expansion (PRE). We find that the X-ray emitting area on the star increases with time as the burst progresses, even though the photosphere does not expand. We argue that this is a strong indication of thermonuclear flame spreading on the stellar surface during such bursts. We propose a model for such double-peaked bursts, based on thermonuclear flame spreading, that can qualitatively explain their essential features, as well as the rarity of these bursts.

Origin of band gap bowing in dilute GaAs1-xNx and GaP1-xNx alloys: A real-space view

NASA Astrophysics Data System (ADS)

Virkkala, Ville; Havu, Ville; Tuomisto, Filip; Puska, Martti J.

2013-07-01

The origin of the band gap bowing in dilute nitrogen doped gallium based III-V semiconductors is largely debated. In this paper we show the dilute GaAs1-xNx and GaP1-xNx as representative examples that the nitrogen-induced states close to the conduction band minimum propagate along the zigzag chains on the {110} planes. Thereby states originating from different N atoms interact with each other resulting in broadening of the nitrogen-induced states which narrows the band gap. Our modeling based on ab initio theoretical calculations explains the experimentally observed N concentration dependent band gap narrowing both qualitatively and quantitatively.

Series: Practical guidance to qualitative research. Part 4: Trustworthiness and publishing.

PubMed

Korstjens, Irene; Moser, Albine

2018-12-01

In the course of our supervisory work over the years we have noticed that qualitative research tends to evoke a lot of questions and worries, so-called frequently asked questions (FAQs). This series of four articles intends to provide novice researchers with practical guidance for conducting high-quality qualitative research in primary care. By 'novice' we mean Master's students and junior researchers, as well as experienced quantitative researchers who are engaging in qualitative research for the first time. This series addresses their questions and provides researchers, readers, reviewers and editors with references to criteria and tools for judging the quality of qualitative research papers. The first article provides an introduction to this series. The second article focused on context, research questions and designs. The third article focused on sampling, data collection and analysis. This fourth article addresses FAQs about trustworthiness and publishing. Quality criteria for all qualitative research are credibility, transferability, dependability, and confirmability. Reflexivity is an integral part of ensuring the transparency and quality of qualitative research. Writing a qualitative research article reflects the iterative nature of the qualitative research process: data analysis continues while writing. A qualitative research article is mostly narrative and tends to be longer than a quantitative paper, and sometimes requires a different structure. Editors essentially use the criteria: is it new, is it true, is it relevant? An effective cover letter enhances confidence in the newness, trueness and relevance, and explains why your study required a qualitative design. It provides information about the way you applied quality criteria or a checklist, and you can attach the checklist to the manuscript.

An Integrated Qualitative and Quantitative Biochemical Model Learning Framework Using Evolutionary Strategy and Simulated Annealing.

PubMed

Wu, Zujian; Pang, Wei; Coghill, George M

2015-01-01

Both qualitative and quantitative model learning frameworks for biochemical systems have been studied in computational systems biology. In this research, after introducing two forms of pre-defined component patterns to represent biochemical models, we propose an integrative qualitative and quantitative modelling framework for inferring biochemical systems. In the proposed framework, interactions between reactants in the candidate models for a target biochemical system are evolved and eventually identified by the application of a qualitative model learning approach with an evolution strategy. Kinetic rates of the models generated from qualitative model learning are then further optimised by employing a quantitative approach with simulated annealing. Experimental results indicate that our proposed integrative framework is feasible to learn the relationships between biochemical reactants qualitatively and to make the model replicate the behaviours of the target system by optimising the kinetic rates quantitatively. Moreover, potential reactants of a target biochemical system can be discovered by hypothesising complex reactants in the synthetic models. Based on the biochemical models learned from the proposed framework, biologists can further perform experimental study in wet laboratory. In this way, natural biochemical systems can be better understood.

Qualitative research methods: key features and insights gained from use in infection prevention research.

PubMed

Forman, Jane; Creswell, John W; Damschroder, Laura; Kowalski, Christine P; Krein, Sarah L

2008-12-01

Infection control professionals and hospital epidemiologists are accustomed to using quantitative research. Although quantitative studies are extremely important in the field of infection control and prevention, often they cannot help us explain why certain factors affect the use of infection control practices and identify the underlying mechanisms through which they do so. Qualitative research methods, which use open-ended techniques, such as interviews, to collect data and nonstatistical techniques to analyze it, provide detailed, diverse insights of individuals, useful quotes that bring a realism to applied research, and information about how different health care settings operate. Qualitative research can illuminate the processes underlying statistical correlations, inform the development of interventions, and show how interventions work to produce observed outcomes. This article describes the key features of qualitative research and the advantages that such features add to existing quantitative research approaches in the study of infection control. We address the goal of qualitative research, the nature of the research process, sampling, data collection and analysis, validity, generalizability of findings, and presentation of findings. Health services researchers are increasingly using qualitative methods to address practical problems by uncovering interacting influences in complex health care environments. Qualitative research methods, applied with expertise and rigor, can contribute important insights to infection prevention efforts.

Learning about general practice through qualitative interviews: lessons from a seminar course with medical students.

PubMed

von Unger, Hella; Werwick, Katrin; Lichte, Thomas; Herrmann, Markus

2010-01-01

A seminar course was developed in order to train medical students in qualitative research methods, while providing an introduction to the field of General Practice. Students were enabled to conduct semi-structured interviews with general practitioners (GPs), during which they learned about the prevention, diagnosis, and treatment of frequently encountered medical problems. The course was carried out four times at two universities in Germany. The study explores the students' learning experiences focusing on their research experience. Data were collected in four focus groups and analyzed. The students perceived the course as very different from their usual medical education. This was appreciated, but also caused some difficulties. Three themes emerged: (1) Missing 'facts', (2) New horizons: 'Thinking outside the box', and (3) The challenge of interpretation: 'Reading between the lines'. Learning qualitative research methods can be particularly challenging for medical students as the tasks and epistemology of qualitative research run counter to the usual learning formats and research paradigms in medical education. When teaching qualitative research, special care should be taken to address the cognitive dissonance experienced by students and to explain the unique contribution of qualitative research to medical practice and the field of General Practice especially.

Fair reckoning: a qualitative investigation of responses to an economic health resource allocation survey.

PubMed

Giacomini, Mita; Hurley, Jeremiah; DeJean, Deirdre

2014-04-01

To investigate how participants in an economic resource allocation survey construct notions of fairness. Qualitative interview study guided by interpretive grounded theory methods. Qualitative interviews were conducted with volunteer university- (n=39) and community-based (n =7) economic survey participants. INTERVENTION OR MAIN VARIABLES STUDIED: We explored how participants constructed meanings to guide or explain fair survey choices, focusing on rationales, imagery and additional desired information not provided in the survey scenarios. Data were transcribed and coded into qualitative categories. Analysis iterated with data collection iterated through three waves of interviews. Participants compared the survey dilemmas to domains outside the health system. Most compared them with other micro-level, inter-personal sharing tasks. Participants raised several fairness-relevant factors beyond need or capacity to benefit. These included age, weight, poverty, access to other options and personal responsibility for illness; illness duration, curability or seriousness; life expectancy; possibilities for sharing; awareness of other's needs; and ability to explain allocations to those affected. They also articulated a fairness principle little considered by equity theories: that everybody must get something and nobody should get nothing. Lay criteria for judging fairness are myriad. Simple scenarios may be used to investigate lay commitments to abstract principles. Although principles are the focus of analysis and inference, participants may solve simplified dilemmas by imputing extraneous features to the problem or applying unanticipated principles. These possibilities should be taken into account in the design of resource allocation surveys eliciting the views of the public. © 2012 John Wiley & Sons Ltd.

Fair reckoning: a qualitative investigation of responses to an economic health resource allocation survey

PubMed Central

Giacomini, Mita; Hurley, Jeremiah; DeJean, Deirdre

2012-01-01

Abstract Objective  To investigate how participants in an economic resource allocation survey construct notions of fairness. Design  Qualitative interview study guided by interpretive grounded theory methods. Setting and participants  Qualitative interviews were conducted with volunteer university‐ (n = 39) and community‐based (n = 7) economic survey participants. Intervention or main variables studied  We explored how participants constructed meanings to guide or explain fair survey choices, focusing on rationales, imagery and additional desired information not provided in the survey scenarios. Main outcome measures  Data were transcribed and coded into qualitative categories. Analysis iterated with data collection iterated through three waves of interviews. Results  Participants compared the survey dilemmas to domains outside the health system. Most compared them with other micro‐level, inter‐personal sharing tasks. Participants raised several fairness‐relevant factors beyond need or capacity to benefit. These included age, weight, poverty, access to other options and personal responsibility for illness; illness duration, curability or seriousness; life expectancy; possibilities for sharing; awareness of other’s needs; and ability to explain allocations to those affected. They also articulated a fairness principle little considered by equity theories: that everybody must get something and nobody should get nothing. Discussion and conclusions  Lay criteria for judging fairness are myriad. Simple scenarios may be used to investigate lay commitments to abstract principles. Although principles are the focus of analysis and inference, participants may solve simplified dilemmas by imputing extraneous features to the problem or applying unanticipated principles. These possibilities should be taken into account in the design of resource allocation surveys eliciting the views of the public. PMID:22390183

77 FR 27738 - Proposed Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-11

... qualitative testing mortgage servicing related model forms and disclosures. DATES: Written comments must be...: Qualitative Testing of Mortgage Servicing Related Model Forms and Disclosures. OMB Number: 3170-0018. Abstract: The Bureau seeks to allow for qualitative testing of mortgage servicing related model forms and...

The long flow to freedom

DOE PAGES

Aharony, Ofer; Razamat, Shlomo S.; Seiberg, Nathan; ...

2017-02-10

Two-dimensional field theories do not have a moduli space of vacua. Instead, it is common that their low-energy behavior is a sigma model with a target space. When this target space is compact its renormalization group flow is standard. When it is non-compact the continuous spectrum of operators can change the qualitative behavior. Here we discuss two-dimensional gauge theories with N = (2,2) supersymmetry. We focus on two specific theories, for which we argue that they flow to free chiral multiplets at low energies: the U(1) gauge theory with one flavor (two chiral superfields with charges plus and minus one)more » and a non-zero Fayet-Iliopoulos term, and pure SU( N) gauge theories. We argue that the renormalization group flow of these theories has an interesting order of limits issue. Holding the position on the target space fixed, the space flattens out under the renormalization group. On the other hand, if we first go to infinity on the target space and then perform the renormalization group, we always have a non-trivial space, e.g. a cone with a deficit angle. We explain how to interpret low-energy dualities between theories with non-compact target spaces. As a result, we expect a similar qualitative behavior also for other non-compact sigma models, even when they do not flow to free theories.« less

Try Fault Tree Analysis, a Step-by-Step Way to Improve Organization Development.

ERIC Educational Resources Information Center

Spitzer, Dean

1980-01-01

Fault Tree Analysis, a systems safety engineering technology used to analyze organizational systems, is described. Explains the use of logic gates to represent the relationship between failure events, qualitative analysis, quantitative analysis, and effective use of Fault Tree Analysis. (CT)

Stream dynamics: An overview for land managers

Treesearch

Burchard H. Heede

1980-01-01

Concepts of stream dynamics are demonstrated through discussion of processes and process indicators; theory is included only where helpful to explain concepts. Present knowledge allows only qualitative prediction of stream behavior. However, such predictions show how management actions will affect the stream and its environment.

A REVIEW OF EPIDEMIOOGICAL STUDIES ON DRINKING WATER HARDNESS AND CARDIOVASCULAR DISEASES

EPA Science Inventory

Major risk factors do not entirely explain the worldwide variability of morbidity and mortality due to

cardiovascular disease. Several environmental factors, including the hardness of drinking water may

affect cardiovascular disease risks. We conducted a qualitative...

Buffered Qualitative Stability explains the robustness and evolvability of transcriptional networks

PubMed Central

Albergante, Luca; Blow, J Julian; Newman, Timothy J

2014-01-01

The gene regulatory network (GRN) is the central decision‐making module of the cell. We have developed a theory called Buffered Qualitative Stability (BQS) based on the hypothesis that GRNs are organised so that they remain robust in the face of unpredictable environmental and evolutionary changes. BQS makes strong and diverse predictions about the network features that allow stable responses under arbitrary perturbations, including the random addition of new connections. We show that the GRNs of E. coli, M. tuberculosis, P. aeruginosa, yeast, mouse, and human all verify the predictions of BQS. BQS explains many of the small- and large‐scale properties of GRNs, provides conditions for evolvable robustness, and highlights general features of transcriptional response. BQS is severely compromised in a human cancer cell line, suggesting that loss of BQS might underlie the phenotypic plasticity of cancer cells, and highlighting a possible sequence of GRN alterations concomitant with cancer initiation. DOI: http://dx.doi.org/10.7554/eLife.02863.001 PMID:25182846

Buffered Qualitative Stability explains the robustness and evolvability of transcriptional networks.

PubMed

Albergante, Luca; Blow, J Julian; Newman, Timothy J

2014-09-02

The gene regulatory network (GRN) is the central decision-making module of the cell. We have developed a theory called Buffered Qualitative Stability (BQS) based on the hypothesis that GRNs are organised so that they remain robust in the face of unpredictable environmental and evolutionary changes. BQS makes strong and diverse predictions about the network features that allow stable responses under arbitrary perturbations, including the random addition of new connections. We show that the GRNs of E. coli, M. tuberculosis, P. aeruginosa, yeast, mouse, and human all verify the predictions of BQS. BQS explains many of the small- and large-scale properties of GRNs, provides conditions for evolvable robustness, and highlights general features of transcriptional response. BQS is severely compromised in a human cancer cell line, suggesting that loss of BQS might underlie the phenotypic plasticity of cancer cells, and highlighting a possible sequence of GRN alterations concomitant with cancer initiation. Copyright © 2014, Albergante et al.

Aging and well-being in French older adults regularly practicing physical activity: a self-determination perspective.

PubMed

Ferrand, Claude; Nasarre, Sandra; Hautier, Christophe; Bonnefoy, Marc

2012-04-01

The purpose of this study was to identify the motivational profiles of physically active older adults and to achieve a better understanding of their perceived motives to explain their regular physical activity behavior in relation to self-determination theory (SDT). To address these aims, this study used quantitative and qualitative approaches. Older adults (n = 92; M = 74.95, SD = 4.6) completed the French version of the Sport Motivational Scale. A cluster analysis showed two motivational profiles with differential motivational patterns. The first was named the high combined profile, with high scores on intrinsic motivation and introjected regulation and low levels of external regulation. The second profile was the low to moderate motivational profile, with low scores on intrinsic motivation and moderate scores on introjected regulation. The qualitative study's results demonstrate the usefulness of SDT in explaining the relationship between these motivational profiles and the intertwining of the three basic psychological needs.

QML-AiNet: An immune network approach to learning qualitative differential equation models

PubMed Central

Pang, Wei; Coghill, George M.

2015-01-01

In this paper, we explore the application of Opt-AiNet, an immune network approach for search and optimisation problems, to learning qualitative models in the form of qualitative differential equations. The Opt-AiNet algorithm is adapted to qualitative model learning problems, resulting in the proposed system QML-AiNet. The potential of QML-AiNet to address the scalability and multimodal search space issues of qualitative model learning has been investigated. More importantly, to further improve the efficiency of QML-AiNet, we also modify the mutation operator according to the features of discrete qualitative model space. Experimental results show that the performance of QML-AiNet is comparable to QML-CLONALG, a QML system using the clonal selection algorithm (CLONALG). More importantly, QML-AiNet with the modified mutation operator can significantly improve the scalability of QML and is much more efficient than QML-CLONALG. PMID:25648212

QML-AiNet: An immune network approach to learning qualitative differential equation models.

PubMed

Pang, Wei; Coghill, George M

2015-02-01

In this paper, we explore the application of Opt-AiNet, an immune network approach for search and optimisation problems, to learning qualitative models in the form of qualitative differential equations. The Opt-AiNet algorithm is adapted to qualitative model learning problems, resulting in the proposed system QML-AiNet. The potential of QML-AiNet to address the scalability and multimodal search space issues of qualitative model learning has been investigated. More importantly, to further improve the efficiency of QML-AiNet, we also modify the mutation operator according to the features of discrete qualitative model space. Experimental results show that the performance of QML-AiNet is comparable to QML-CLONALG, a QML system using the clonal selection algorithm (CLONALG). More importantly, QML-AiNet with the modified mutation operator can significantly improve the scalability of QML and is much more efficient than QML-CLONALG.

Activation of the maternal caregiving system by childhood fever--a qualitative study of the experiences made by mothers with a German or a Turkish background in the care of their children.

PubMed

Langer, Thorsten; Pfeifer, Miriam; Soenmez, Aynur; Kalitzkus, Vera; Wilm, Stefan; Schnepp, Wilfried

2013-03-18

Childhood fever represents a frequent cause to consult a primary care physician. "Fever phobia" describes a fearful and irrational view of fever shared by many parents with different cultural backgrounds. The study aims to explain the experiences of mothers of children having a fever and to analyze the role of the mothers' cultural background with regard to their experiences by comparing the accounts of mothers with a German with those from a Turkish background. Disease and context specific knowledge about the influence of culture can be important for effective counselling. We applied a qualitative approach using in-depth interviews with 11 mothers with a Turkish and 9 with a German background living in Germany. The interviews were conducted at the participants' homes from May to October 2008. Data was audio-recorded and transcribed verbatim. Grounded Theory was used as a framing methodology including open, axial and selective coding. Analysis was performed in a group with members of different professional and cultural backgrounds. Mothers experienced their child's fever not merely as elevated temperature but as a potentially dangerous event. A deeply rooted urge to protect the child from harm was central to all participants' experience. The caregiving system model offers a good theoretical foundation to explain the findings as it incorporates the unique relational quality of care giving mothers to their children. The cultural background represents an important context variable influencing the explanatory models and strategies of dealing with fever. The identified culturally influenced concepts sometimes match and sometimes conflict with medical knowledge. By applying the caregiving system model which is a part of attachment theory (Bowlby) maternal actions can be understood as an understandable attempt to protect the child from harm. The mothers' decisions what to do when a child has a fever can be culturally influenced. This may lead either to a frequent use of services or to an underestimation of the child's state of health. The mothers' caring role and emotional state should be acknowledged; her concerns, explanatory models and strategies should be elicited and taken seriously in order to maintain a trustful relationship, provide effective counselling and thereby insuring optimal care for the children.

Activation of the maternal caregiving system by childhood fever – a qualitative study of the experiences made by mothers with a German or a Turkish background in the care of their children

PubMed Central

2013-01-01

Background Childhood fever represents a frequent cause to consult a primary care physician. “Fever phobia” describes a fearful and irrational view of fever shared by many parents with different cultural backgrounds. The study aims to explain the experiences of mothers of children having a fever and to analyze the role of the mothers’ cultural background with regard to their experiences by comparing the accounts of mothers with a German with those from a Turkish background. Disease and context specific knowledge about the influence of culture can be important for effective counselling. Methods We applied a qualitative approach using in-depth interviews with 11 mothers with a Turkish and 9 with a German background living in Germany. The interviews were conducted at the participants´ homes from May to October 2008. Data was audio-recorded and transcribed verbatim. Grounded Theory was used as a framing methodology including open, axial and selective coding. Analysis was performed in a group with members of different professional and cultural backgrounds. Results Mothers experienced their child’s fever not merely as elevated temperature but as a potentially dangerous event. A deeply rooted urge to protect the child from harm was central to all participants’ experience. The caregiving system model offers a good theoretical foundation to explain the findings as it incorporates the unique relational quality of care giving mothers to their children. The cultural background represents an important context variable influencing the explanatory models and strategies of dealing with fever. The identified culturally influenced concepts sometimes match and sometimes conflict with medical knowledge. Conclusion By applying the caregiving system model which is a part of attachment theory (Bowlby) maternal actions can be understood as an understandable attempt to protect the child from harm. The mothers´ decisions what to do when a child has a fever can be culturally influenced. This may lead either to a frequent use of services or to an underestimation of the child’s state of health. The mothers´ caring role and emotional state should be acknowledged; her concerns, explanatory models and strategies should be elicited and taken seriously in order to maintain a trustful relationship, provide effective counselling and thereby insuring optimal care for the children. PMID:23506372

Exploring the feelings of Iranian women of reproductive age about health care seeking behavior: a qualitative study.

PubMed

Morowatisharifabad, Mohammad Ali; Rahimi, Tahereh; Farajkhoda, Tahmineh; Fallahzadeh, Hossein; Mohebi, Siamak

2018-01-01

Background: Despite the important role of feelings in health care seeking behavior (HCSB), this subject has not yet been adequately investigated. HCSB-related feelings begin with the onset of disease symptoms and persist in different forms after treatment. The aim of current study was to explore the feelings that women of reproductive age experience when they seek health care. Methods: In this deductive, qualitative content analysis, participants were selected by purposeful sampling. Semi-structured, in-depth interviews with 17 women of reproductive age and 5 health care staffs in Qom, Iran were carried out until data saturation was achieved. Qualitative data were concurrently analyzed by deductive content analysis, using the Health Promotion Model (HPM). The MAXQDA10 software was used to manage qualitative data analysis. Results: Three main categories were drawn from data to explain the HCSB-related feelings of participants consisting of (1) feeling of inner satisfaction with the treatment with 2 subcategories including "peace of mind" and "feeling alive", (2) multiple roles of fear with 5 subcategories including "fear about the consequences of delay", "fear of having hidden diseases", "fear of unknown experiences", "fear of hearing bad news" and "fear of medical errors" and (3)uncomfortable feelings with 3 subcategories including "feeling uneasy when attending health facility", "feeling embarrassed" and "feeling worthless due to dealing the doctor". Conclusion: This study revealed that the inner feelings of women varied widely, ranging from positive or motivating feelings to negative or inhibitory ones, given their experiences with the formal health care system and the current situation of medical and health services. Highlighting patients' perceived inner satisfaction and reducing fear and uncomfortable feelings by adopting culture-based practical strategies can enhance women's HCSB.

The Use of Mixed Methods for Therapeutic Massage Research

PubMed Central

Porcino, Antony Joseph; Verhoef, Marja J.

2010-01-01

Mixed methods research is the integration of quantitative and qualitative components in a research project. Whether you are reading or designing a mixed methods research project, it is important to be familiar with both qualitative and quantitative research methods and the specific purposes for which they are brought together in a study: triangulation, complementarity, expansion, initiation, or development. In addition, decisions need to be made about the sequencing and the priority or importance of each qualitative and quantitative component relative to the other components, and the point or points at which the various qualitative and quantitative components will be integrated. Mixed methods research is increasingly being recognized for its ability to bring multiple points of view to a research project, taking advantage of the strengths of each of the quantitative and qualitative components to explain or resolve complex phenomena or results. This ability becomes critical when complex healing systems such as therapeutic massage are being studied. Complex healing systems may have multiple physiologic effects, often reflected in changes throughout the patient’s body. Additionally, the patient’s experience of the treatment may be an important outcome. PMID:21589698

Use of qualitative methods alongside randomised controlled trials of complex healthcare interventions: methodological study

PubMed Central

Glenton, Claire; Oxman, Andrew D

2009-01-01

Objective To examine the use of qualitative approaches alongside randomised trials of complex healthcare interventions. Design Review of randomised controlled trials of interventions to change professional practice or the organisation of care. Data sources Systematic sample of 100 trials published in English from the register of the Cochrane Effective Practice and Organisation of Care Review Group. Methods Published and unpublished qualitative studies linked to the randomised controlled trials were identified through database searches and contact with authors. Data were extracted from each study by two reviewers using a standard form. We extracted data describing the randomised controlled trials and qualitative studies, the quality of these studies, and how, if at all, the qualitative and quantitative findings were combined. A narrative synthesis of the findings was done. Results 30 of the 100 trials had associated qualitative work and 19 of these were published studies. 14 qualitative studies were done before the trial, nine during the trial, and four after the trial. 13 studies reported an explicit theoretical basis and 11 specified their methodological approach. Approaches to sampling and data analysis were poorly described. For most cases (n=20) we found no indication of integration of qualitative and quantitative findings at the level of either analysis or interpretation. The quality of the qualitative studies was highly variable. Conclusions Qualitative studies alongside randomised controlled trials remain uncommon, even where relatively complex interventions are being evaluated. Most of the qualitative studies were carried out before or during the trials with few studies used to explain trial results. The findings of the qualitative studies seemed to be poorly integrated with those of the trials and often had major methodological shortcomings. PMID:19744976

The morals of model-making.

PubMed

Sterrett, S G

2014-06-01

I address questions about values in model-making in engineering, specifically: Might the role of values be attributable solely to interests involved in specifying and using the model? Selected examples illustrate the surprisingly wide variety of things one must take into account in the model-making itself. The notions of system (as used in engineering thermodynamics), and physically similar systems (as used in the physical sciences) are important and powerful in determining what is relevant to an engineering model. Another example (windfarms) illustrates how an idea to completely re-characterize, or reframe, an engineering problem arose during model-making. I employ a qualitative analogue of the notion of physically similar systems. Historical cases can thus be drawn upon; I illustrate with a comparison between a geoengineering proposal to inject, or spray, sulfate aerosols, and two different historical cases involving the spraying of DDT (fire ant eradication; malaria eradication). The current geoengineering proposal is seen to be like the disastrous and counterproductive case, and unlike the successful case, of the spraying of DDT. I conclude by explaining my view that model-making in science is analogous to moral perception in action, drawing on a view in moral theory that has come to be called moral particularism.

An "age"-structured model of hematopoietic stem cell organization with application to chronic myeloid leukemia.

PubMed

Roeder, Ingo; Herberg, Maria; Horn, Matthias

2009-04-01

Previously, we have modeled hematopoietic stem cell organization by a stochastic, single cell-based approach. Applications to different experimental systems demonstrated that this model consistently explains a broad variety of in vivo and in vitro data. A major advantage of the agent-based model (ABM) is the representation of heterogeneity within the hematopoietic stem cell population. However, this advantage comes at the price of time-consuming simulations if the systems become large. One example in this respect is the modeling of disease and treatment dynamics in patients with chronic myeloid leukemia (CML), where the realistic number of individual cells to be considered exceeds 10(6). To overcome this deficiency, without losing the representation of the inherent heterogeneity of the stem cell population, we here propose to approximate the ABM by a system of partial differential equations (PDEs). The major benefit of such an approach is its independence from the size of the system. Although this mean field approach includes a number of simplifying assumptions compared to the ABM, it retains the key structure of the model including the "age"-structure of stem cells. We show that the PDE model qualitatively and quantitatively reproduces the results of the agent-based approach.

Enhancing Environmental Communication and Products Through Qualitative Research

NASA Astrophysics Data System (ADS)

DeLorme, D.; Hagen, S. C.

2014-12-01

This presentation discusses two ongoing interdisciplinary case studies that are using qualitative research to design and enhance environmental communication and science products for outreach and decision making purposes. Both cases demonstrate the viability and practical value of qualitative social science methodology, specifically focus group interviews, to better understand the viewpoints of target audiences, improve deliverables, and support project goals. The first case is a NOAA-funded project to conduct process-based modeling to project impact from climate change in general and sea level rise in particular to the natural and built environment. The project spans the Mississippi, Alabama, and Florida Panhandle coasts with concentration on the three National Estuarine Research Reserves. As part of the broader project, four annual focus groups were conducted with a purposive sample of coastal resource managers to capture their perspectives and suggestions to better meet their informational and operational needs. The second case is a Florida Sea Grant-funded project that is developing, implementing, and testing a cohesive outreach campaign to promote voluntary careful and responsible recreational boating to help protect sensitive marine life and habitats (especially seagrasses and oyster reefs) in the Mosquito Lagoon. Six focus groups were conducted with a purposive sample of the target audience of boaters to gain insights, feedback, and ideas on the direction of the campaign and design of the messages and products. The campaign materials created include a branded website, Facebook page, mobile app, information packets, brochures, pledge forms, and promotional items. A comparison of these two case studies will be provided and will explain how the qualitative findings were/are being implemented to tailor and refine the respective communication strategies and techniques including the emerging outreach products. The resulting outcomes are messages and tools that are readily accessible, understandable, engaging, useful, and memorable to the target audiences. The presentation will conclude with an overview of the strengths and role of qualitative methodology, how this approach can help address other science communication needs, and future research recommendations.

Iterative categorization (IC): a systematic technique for analysing qualitative data.

PubMed

Neale, Joanne

2016-06-01

The processes of analysing qualitative data, particularly the stage between coding and publication, are often vague and/or poorly explained within addiction science and research more broadly. A simple but rigorous and transparent technique for analysing qualitative textual data, developed within the field of addiction, is described. The technique, iterative categorization (IC), is suitable for use with inductive and deductive codes and can support a range of common analytical approaches, e.g. thematic analysis, Framework, constant comparison, analytical induction, content analysis, conversational analysis, discourse analysis, interpretative phenomenological analysis and narrative analysis. Once the data have been coded, the only software required is a standard word processing package. Worked examples are provided. © 2016 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

PANCHROMATIC HUBBLE ANDROMEDA TREASURY. XVI. STAR CLUSTER FORMATION EFFICIENCY AND THE CLUSTERED FRACTION OF YOUNG STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, L. Clifton; Sandstrom, Karin; Seth, Anil C.

We use the Panchromatic Hubble Andromeda Treasury survey data set to perform spatially resolved measurements of star cluster formation efficiency (Γ), the fraction of stellar mass formed in long-lived star clusters. We use robust star formation history and cluster parameter constraints, obtained through color–magnitude diagram analysis of resolved stellar populations, to study Andromeda’s cluster and field populations over the last ∼300 Myr. We measure Γ of 4%–8% for young, 10–100 Myr-old populations in M31. We find that cluster formation efficiency varies systematically across the M31 disk, consistent with variations in mid-plane pressure. These Γ measurements expand the range of well-studiedmore » galactic environments, providing precise constraints in an H i-dominated, low-intensity star formation environment. Spatially resolved results from M31 are broadly consistent with previous trends observed on galaxy-integrated scales, where Γ increases with increasing star formation rate surface density (Σ{sub SFR}). However, we can explain observed scatter in the relation and attain better agreement between observations and theoretical models if we account for environmental variations in gas depletion time ( τ {sub dep}) when modeling Γ, accounting for the qualitative shift in star formation behavior when transitioning from a H{sub 2}-dominated to a H i-dominated interstellar medium. We also demonstrate that Γ measurements in high Σ{sub SFR} starburst systems are well-explained by τ {sub dep}-dependent fiducial Γ models.« less

Probability of Detection (POD) as a statistical model for the validation of qualitative methods.

PubMed

Wehling, Paul; LaBudde, Robert A; Brunelle, Sharon L; Nelson, Maria T

2011-01-01

A statistical model is presented for use in validation of qualitative methods. This model, termed Probability of Detection (POD), harmonizes the statistical concepts and parameters between quantitative and qualitative method validation. POD characterizes method response with respect to concentration as a continuous variable. The POD model provides a tool for graphical representation of response curves for qualitative methods. In addition, the model allows comparisons between candidate and reference methods, and provides calculations of repeatability, reproducibility, and laboratory effects from collaborative study data. Single laboratory study and collaborative study examples are given.

Studies with spike initiators - Linearization by noise allows continuous signal modulation in neural networks

NASA Technical Reports Server (NTRS)

Yu, Xiaolong; Lewis, Edwin R.

1989-01-01

It is shown that noise can be an important element in the translation of neuronal generator potentials (summed inputs) to neuronal spike trains (outputs), creating or expanding a range of amplitudes over which the spike rate is proportional to the generator potential amplitude. Noise converts the basically nonlinear operation of a spike initiator into a nearly linear modulation process. This linearization effect of noise is examined in a simple intuitive model of a static threshold and in a more realistic computer simulation of spike initiator based on the Hodgkin-Huxley (HH) model. The results are qualitatively similar; in each case larger noise amplitude results in a larger range of nearly linear modulation. The computer simulation of the HH model with noise shows linear and nonlinear features that were earlier observed in spike data obtained from the VIIIth nerve of the bullfrog. This suggests that these features can be explained in terms of spike initiator properties, and it also suggests that the HH model may be useful for representing basic spike initiator properties in vertebrates.

Generation of longitudinal vibrations in piano strings: From physics to sound synthesis

NASA Astrophysics Data System (ADS)

Bank, Balázs; Sujbert, László

2005-04-01

Longitudinal vibration of piano strings greatly contributes to the distinctive character of low piano notes. In this paper a simplified modal model is developed, which describes the generation of phantom partials and longitudinal free modes jointly. The model is based on the simplification that the coupling from the transverse vibration to the longitudinal polarization is unidirectional. The modal formulation makes it possible to predict the prominent components of longitudinal vibration as a function of transverse modal frequencies. This provides a qualitative insight into the generation of longitudinal vibration, while the model is still capable of explaining the empirical results of earlier works. The semi-quantitative agreement with measurement results implies that the main source of phantom partials is the transverse to longitudinal coupling, while the string termination and the longitudinal to transverse coupling have only small influence. The results suggest that the longitudinal component of the tone can be treated as a quasi-harmonic spectrum with formantlike peaks at the longitudinal modal frequencies. The model is further simplified and applied for the real-time synthesis of piano sound with convincing sonic results. .

Computer Simulation Elucidates Yeast Flocculation and Sedimentation for Efficient Industrial Fermentation.

PubMed

Liu, Chen-Guang; Li, Zhi-Yang; Hao, Yue; Xia, Juan; Bai, Feng-Wu; Mehmood, Muhammad Aamer

2018-05-01

Flocculation plays an important role in the immobilized fermentation of biofuels and biochemicals. It is essential to understand the flocculation phenomenon at physical and molecular scale; however, flocs cannot be studied directly due to fragile nature. Hence, the present study is focused on the morphological specificities of yeast flocs formation and sedimentation via the computer simulation by a single floc growth model, based on Diffusion-Limited Aggregation (DLA) model. The impact of shear force, adsorption, and cell propagation on porosity and floc size is systematically illustrated. Strong shear force and weak adsorption reduced floc size but have little impact on porosity. Besides, cell propagation concreted the compactness of flocs enabling them to gain a larger size. Later, a multiple flocs growth model is developed to explain sedimentation at various initial floc sizes. Both models exhibited qualitative agreements with available experimental data. By regulating the operation constraints during fermentation, the present study will lead to finding optimal conditions to control the floc size distribution for efficient fermentation and harvesting. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

International Field Experiences Promote Professional Development for Sustainability Leaders

ERIC Educational Resources Information Center

Hull, R. Bruce; Kimmel, Courtney; Robertson, David P.; Mortimer, Michael

2016-01-01

Purpose: This paper aims to describe, explain and evaluate a graduate education program that provides international project experiences and builds competencies related to collaborative problem-solving, cultural capacity to work globally and sustainable development. Design/methodology/approach: Qualitative analysis of survey data from 28 students…

Online Collaborative Learning and Communication Media

ERIC Educational Resources Information Center

Havard, Byron; Du, Jianxia; Xu, Jianzhong

2008-01-01

The purpose of this study is to examine the dynamics of online collaborative learning and communication media regarding team projects. Media richness and social presence theories are well-accepted rational theories that explain media choices and media behaviors, and serve as the theoretical framework. Quantitative and qualitative data collection…

VLTI/AMBER spectro-interferometric imaging of VX Sagittarii's inhomogenous outer atmosphere

NASA Astrophysics Data System (ADS)

Chiavassa, A.; Lacour, S.; Millour, F.; Driebe, T.; Wittkowski, M.; Plez, B.; Thiébaut, E.; Josselin, E.; Freytag, B.; Scholz, M.; Haubois, X.

2010-02-01

Aims: We aim to explore the photosphere of the very cool late-type star VX Sgr and in particular the characterization of molecular layers above the continuum forming photosphere. Methods: We obtained interferometric observations with the VLTI/AMBER interferometer using the fringe tracker FINITO in the spectral domain 1.45-2.50 μm with a spectral resolution of ≈35 and baselines ranging from 15 to 88 m. We performed independent image reconstruction for different wavelength bins and fit the interferometric data with a geometrical toy model. We also compared the data to 1D dynamical models of Miras atmosphere and to 3D hydrodynamical simulations of red supergiant (RSG) and asymptotic giant branch (AGB) stars. Results: Reconstructed images and visibilities show a strong wavelength dependence. The H-band images display two bright spots whose positions are confirmed by the geometrical toy model. The inhomogeneities are qualitatively predicted by 3D simulations. At ≈2.00 μm and in the region 2.35-2.50 μm, the photosphere appears extended and the radius is larger than in the H band. In this spectral region, the geometrical toy model locates a third bright spot outside the photosphere that can be a feature of the molecular layers. The wavelength dependence of the visibility can be qualitatively explained by 1D dynamical models of Mira atmospheres. The best-fitting photospheric models show a good match with the observed visibilities and give a photospheric diameter of Theta=8.82 ± 0.50 mas. The H2O molecule seems to be the dominant absorber in the molecular layers. Conclusions: We show that the atmosphere of VX Sgr seems to resemble Mira/AGB star model atmospheres more closely than do RSG model atmospheres. In particular, we see molecular (water) layers that are typical of Mira stars. Based on the observations made with VLTI-ESO Paranal, Chile under the programs IDs 081.D-0005(A, B, C, D, E, F, G, H).

Developing a conceptual model for the application of patient and public involvement in the healthcare system in Iran.

PubMed

Azmal, Mohammad; Sari, Ali Akbari; Foroushani, Abbas Rahimi; Ahmadi, Batoul

2016-06-01

Patient and public involvement is engaging patients, providers, community representatives, and the public in healthcare planning and decision-making. The purpose of this study was to develop a model for the application of patient and public involvement in decision making in the Iranian healthcare system. A mixed qualitative-quantitative approach was used to develop a conceptual model. Thirty three key informants were purposely recruited in the qualitative stage, and 420 people (patients and their companions) were included in a protocol study that was implemented in five steps: 1) Identifying antecedents, consequences, and variables associated with the patient and the publics' involvement in healthcare decision making through a comprehensive literature review; 2) Determining the main variables in the context of Iran's health system using conceptual framework analysis; 3) Prioritizing and weighting variables by Shannon entropy; 4) designing and validating a tool for patient and public involvement in healthcare decision making; and 5) Providing a conceptual model of patient and the public involvement in planning and developing healthcare using structural equation modeling. We used various software programs, including SPSS (17), Max QDA (10), EXCEL, and LISREL. Content analysis, Shannon entropy, and descriptive and analytic statistics were used to analyze the data. In this study, seven antecedents variable, five dimensions of involvement, and six consequences were identified. These variables were used to design a valid tool. A logical model was derived that explained the logical relationships between antecedent and consequent variables and the dimensions of patient and public involvement as well. Given the specific context of the political, social, and innovative environments in Iran, it was necessary to design a model that would be compatible with these features. It can improve the quality of care and promote the patient and the public satisfaction with healthcare and legitimate the representative of people they served for. This model can provide a practical guide for managers and policy makers to involve people in making the decisions that influence their lives.

Knowledge representation and qualitative simulation of salmon redd functioning. Part II: qualitative model of redds.

PubMed

Guerrin, F; Dumas, J

2001-02-01

This paper describes a qualitative model of the functioning of salmon redds (spawning areas of salmon) and its impact on mortality rates of early stages. For this, we use Qsim, a qualitative simulator, which appeared adequate for representing available qualitative knowledge of freshwater ecology experts (see Part I of this paper). Since the number of relevant variables was relatively large, it appeared necessary to decompose the model into two parts, corresponding to processes occurring at separate time-scales. A qualitative clock allows us to submit the simulation of salmon developmental stages to the calculation of accumulated daily temperatures (degree-days), according to the clock ticks and a water temperature regime set by the user. Therefore, this introduces some way of real-time dating and duration in a purely qualitative model. Simulating both sub-models, either separately or by means of alternate transitions, allows us to generate the evolutions of variables of interest, such as the mortality rates according to two factors (flow of oxygenated water and plugging of gravel interstices near the bed surface), under various scenarios.

Learning about Ecological Systems by Constructing Qualitative Models with DynaLearn

ERIC Educational Resources Information Center

Leiba, Moshe; Zuzovsky, Ruth; Mioduser, David; Benayahu, Yehuda; Nachmias, Rafi

2012-01-01

A qualitative model of a system is an abstraction that captures ordinal knowledge and predicts the set of qualitatively possible behaviours of the system, given a qualitative description of its structure and initial state. This paper examines an innovative approach to science education using an interactive learning environment that supports…

Qualitative approaches to use of the RE-AIM framework: rationale and methods.

PubMed

Holtrop, Jodi Summers; Rabin, Borsika A; Glasgow, Russell E

2018-03-13

There have been over 430 publications using the RE-AIM model for planning and evaluation of health programs and policies, as well as numerous applications of the model in grant proposals and national programs. Full use of the model includes use of qualitative methods to understand why and how results were obtained on different RE-AIM dimensions, however, recent reviews have revealed that qualitative methods have been used infrequently. Having quantitative and qualitative methods and results iteratively inform each other should enhance understanding and lessons learned. Because there have been few published examples of qualitative approaches and methods using RE-AIM for planning or assessment and no guidance on how qualitative approaches can inform these processes, we provide guidance on qualitative methods to address the RE-AIM model and its various dimensions. The intended audience is researchers interested in applying RE-AIM or similar implementation models, but the methods discussed should also be relevant to those in community or clinical settings. We present directions for, examples of, and guidance on how qualitative methods can be used to address each of the five RE-AIM dimensions. Formative qualitative methods can be helpful in planning interventions and designing for dissemination. Summative qualitative methods are useful when used in an iterative, mixed methods approach for understanding how and why different patterns of results occur. In summary, qualitative and mixed methods approaches to RE-AIM help understand complex situations and results, why and how outcomes were obtained, and contextual factors not easily assessed using quantitative measures.

Qualitative study about the ways teachers react to feedback from resident evaluations

PubMed Central

2013-01-01

Background Currently, one of the main interventions that are widely expected to contribute to teachers’ professional development is confronting teachers with feedback from resident evaluations of their teaching performance. Receiving feedback, however, is a double edged sword. Teachers see themselves confronted with information about themselves and are, at the same time, expected to be role models in the way they respond to feedback. Knowledge about the teachers’ responses could be not only of benefit for their professional development, but also for supporting their role modeling. Therefore, research about professional development should include the way teachers respond to feedback. Method We designed a qualitative study with semi-structured individual conversations about feedback reports, gained from resident evaluations. Two researchers carried out a systematic analysis using qualitative research software. The analysis focused on what happened in the conversations and structured the data in three main themes: conversation process, acceptance and coping strategies. Results The result section describes the conversation patterns and atmosphere. Teachers accepted their results calmly, stating that, although they recognised some points of interest, they could not meet with every standard. Most used coping strategies were explaining the results from their personal beliefs about good teaching and attributing poor results to external factors and good results to themselves. However, some teachers admitted that they had poor results because of the fact that they were not “sharp enough” in their resident group, implying that they did not do their best. Conclusions Our study not only confirms that the effects of feedback depend first and foremost on the recipient but also enlightens the meaning and role of acceptance and being a role model. We think that the results justify the conclusion that teachers who are responsible for the day release programmes in the three departments tend to respond to the evaluation results just like human beings do and, at the time of the conversation, are initially not aware of the fact that they are role models in the way they respond to feedback. PMID:23866849

Student Satisfaction With Blackboard-Style Videos.

PubMed

Wolf, Andrew B; Peyre, Sarah E

2018-04-19

Blackboard-style videos with simple drawings illustrating concepts have become immensely popular in recent years. However, there has been no published research evaluating their efficacy in nursing education. This pilot study evaluates the use of blackboard-style videos in an online pathophysiology course. Quantitative and qualitative evaluation data were analyzed to evaluate student satisfaction. The data indicated that students were highly satisfied with the course and the delivery of content using blackboard-style videos. The qualitative analysis uncovered two key themes explaining the high level of satisfaction: visual plus narrative explanations support learning and student control over pacing enhances learning.

A mixed methods contribution to the study of health public policies: complementarities and difficulties

PubMed Central

2015-01-01

The use of mixed methods (combining quantitative and qualitative data) is developing in a variety of forms, especially in the health field. Our own research has adopted this perspective from the outset. We have sought all along to innovate in various ways and especially to develop an equal partnership, in the sense of not allowing any single approach to dominate. After briefly describing mixed methods, in this article we explain and illustrate how we have exploited both qualitative and quantitative methods to answer our research questions, ending with a reflective analysis of our experiment. PMID:26559730

CONFIG - Adapting qualitative modeling and discrete event simulation for design of fault management systems

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Basham, Bryan D.

1989-01-01

CONFIG is a modeling and simulation tool prototype for analyzing the normal and faulty qualitative behaviors of engineered systems. Qualitative modeling and discrete-event simulation have been adapted and integrated, to support early development, during system design, of software and procedures for management of failures, especially in diagnostic expert systems. Qualitative component models are defined in terms of normal and faulty modes and processes, which are defined by invocation statements and effect statements with time delays. System models are constructed graphically by using instances of components and relations from object-oriented hierarchical model libraries. Extension and reuse of CONFIG models and analysis capabilities in hybrid rule- and model-based expert fault-management support systems are discussed.

Reverberant acoustic energy in auditoria that comprise systems of coupled rooms

NASA Astrophysics Data System (ADS)

Summers, Jason E.

2003-11-01

A frequency-dependent model for reverberant energy in coupled rooms is developed and compared with measurements for a 1:10 scale model and for Bass Hall, Ft. Worth, TX. At high frequencies, prior statistical-acoustics models are improved by geometrical-acoustics corrections for decay within sub-rooms and for energy transfer between sub-rooms. Comparisons of computational geometrical acoustics predictions based on beam-axis tracing with scale model measurements indicate errors resulting from tail-correction assuming constant quadratic growth of reflection density. Using ray tracing in the late part corrects this error. For mid-frequencies, the models are modified to account for wave effects at coupling apertures by including power transmission coefficients. Similarly, statical-acoustics models are improved through more accurate estimates of power transmission measurements. Scale model measurements are in accord with the predicted behavior. The edge-diffraction model is adapted to study transmission through apertures. Multiple-order scattering is theoretically and experimentally shown inaccurate due to neglect of slope diffraction. At low frequencies, perturbation models qualitatively explain scale model measurements. Measurements confirm relation of coupling strength to unperturbed pressure distribution on coupling surfaces. Measurements in Bass Hall exhibit effects of the coupled stage house. High frequency predictions of statistical acoustics and geometrical acoustics models and predictions of coupling apertures all agree with measurements.

Qualitative cross-sectional study of the perceived causes of depression in South Asian origin women in Toronto

PubMed Central

Ekanayake, Samanthika; Ahmad, Farah

2012-01-01

Objective To explore how South Asian origin women in Toronto, Canada, understand and explain the causes of their depression. Design Cross-sectional in-depth qualitative interviews. Setting Outpatient service in Toronto, Ontario. Participants Ten women with symptoms of depression aged between 22 and 65 years of age. Seven were from India, two from Sri Lanka and one from Pakistan. Four were Muslim, three Hindu and three Catholic. Two participants had university degrees, one a high school diploma and seven had completed less than a high school education. Eight were married, one was unmarried and one a widow. Results Three main factors emerged from the participant narratives as the causes of depression: family and relationships, culture and migration and socioeconomic. The majority of the participants identified domestic abuse, marital problems and interpersonal problems in the family as the cause of their depression. Culture and migration and socioeconomic factors were considered contributory. None of our study participants reported spiritual, supernatural or religious factors as causes of depression. Conclusion A personal–social–cultural model emerged as the aetiological paradigm for depression. Given the perceived causation, psycho-social treatment methods may be more acceptable for South Asian origin women. PMID:22337816

Qualitative cross-sectional study of the perceived causes of depression in South Asian origin women in Toronto.

PubMed

Ekanayake, Samanthika; Ahmad, Farah; McKenzie, Kwame

2012-01-01

To explore how South Asian origin women in Toronto, Canada, understand and explain the causes of their depression. Cross-sectional in-depth qualitative interviews. Outpatient service in Toronto, Ontario. Ten women with symptoms of depression aged between 22 and 65 years of age. Seven were from India, two from Sri Lanka and one from Pakistan. Four were Muslim, three Hindu and three Catholic. Two participants had university degrees, one a high school diploma and seven had completed less than a high school education. Eight were married, one was unmarried and one a widow. Three main factors emerged from the participant narratives as the causes of depression: family and relationships, culture and migration and socioeconomic. The majority of the participants identified domestic abuse, marital problems and interpersonal problems in the family as the cause of their depression. Culture and migration and socioeconomic factors were considered contributory. None of our study participants reported spiritual, supernatural or religious factors as causes of depression. A personal-social-cultural model emerged as the aetiological paradigm for depression. Given the perceived causation, psycho-social treatment methods may be more acceptable for South Asian origin women.

"What Could Have Been Different": A Qualitative Study of Syndemic Theory and HIV Prevention among Young Men Who Have Sex with Men.

PubMed

Lyons, Thomas; Johnson, Amy K; Garofalo, Robert

2013-01-01

Young men who have sex with men (MSM) experience multiple health disparities, including alcohol and drug use, partner violence, victimization due to sexual orientation, and HIV infection. Syndemic theorists explain the clustering of these disparities among adult MSM as a result of cultural marginalization. To date, research on a similar emerging syndemic among young MSM has been limited to quantitative studies. This study seeks to better understand these disparities, and how they may cluster together, via qualitative interviews with 21 ethnically diverse, HIV infected young MSM aged 18-24 years old. These youth report a lack of gay-specific HIV prevention education, absence of role models, and lack of productive future goal-related activities as factors related to their acquisition of HIV, and downplay substance use as a factor. Although not necessarily the components traditionally cited by syndemic theorists, these findings support the notion that multiple factors of cultural marginalization cluster together in the lives of young MSM, and underscore the importance of community-level interventions, such as sexual health education, access to mentors, and assistance with future goal setting and planning.

Liquid gallium-lead mixture phase diagram, surface tension near the critical mixing point, and prewetting transition.

PubMed

Osman, S M; Grosdidier, B; Ali, I; Abdellah, A Ben

2013-06-01

Quite recently, we reported a semianalytical equation of state (EOS) for the Ga-Pb alloy [Phys. Rev. B 78, 024205 (2008)], which was based on the first-order perturbation theory of fluid mixtures, within the simplified random phase approximation, in conjunction with the Grosdidier et al. model pair potentials for Ga-Ga and Pb-Pb with a suitable nonadditive pair potential between Ga-Pb unlike pairs. In the present work, we employ the present EOS to calculate the Ga-Pb phase diagram along the immiscibility gap region. The accuracy of the EOS is tested by consulting the empirical binodal curve. A statistical-mechanical-based theory for the surface tension is employed to obtain an analytical expression for the alloy surface tension. We calculated the surface tension along the bimodal curve and at extreme conditions of temperatures and pressures. The surface tension exhibits reasonably well the prewetting transition of Pb atoms at the surface of the Ga-rich liquid alloy and could qualitatively explain the prewetting phenomena occurring in the Ga-rich side of the phase diagram. The predicted prewetting line and wetting temperature qualitatively agree with the empirical measurements.

“What Could Have Been Different”: A Qualitative Study of Syndemic Theory and HIV Prevention among Young Men Who Have Sex with Men

PubMed Central

Lyons, Thomas; Johnson, Amy K.; Garofalo, Robert

2013-01-01

Young men who have sex with men (MSM) experience multiple health disparities, including alcohol and drug use, partner violence, victimization due to sexual orientation, and HIV infection. Syndemic theorists explain the clustering of these disparities among adult MSM as a result of cultural marginalization. To date, research on a similar emerging syndemic among young MSM has been limited to quantitative studies. This study seeks to better understand these disparities, and how they may cluster together, via qualitative interviews with 21 ethnically diverse, HIV infected young MSM aged 18–24 years old. These youth report a lack of gay-specific HIV prevention education, absence of role models, and lack of productive future goal-related activities as factors related to their acquisition of HIV, and downplay substance use as a factor. Although not necessarily the components traditionally cited by syndemic theorists, these findings support the notion that multiple factors of cultural marginalization cluster together in the lives of young MSM, and underscore the importance of community-level interventions, such as sexual health education, access to mentors, and assistance with future goal setting and planning. PMID:24244112

An introspective qualitative report on dietary patterns and elevated levels of dental decay in a deprived urban population in northern Mexico.

PubMed

Maupomé, G

1998-01-01

Disorganized urbanization in Latin America has led to masses of impoverished people to become squatters in the larger urban areas. Using a community development network in the outskirts of Tijuana, in Northern Mexico, this investigation assessed the dental health situation, aiming to establish the underlying behavioral causes of poor oral health in these slums. Using quantitative and qualitative tools, fifty-six mothers (mean age 30.1 +/- 7.2) with their accompanying children (n = 56; mean age 6.1 +/- 3.3; 46.4 percent female) were interviewed and examined. Dental health was poor and characterized by vast unmet treatment needs in adults and children. 22.2 percent of children under three years of age suffered from Early Childhood Caries, strongly linked to inappropriate patterns of bottle use. Dietary patterns for the overall child population included many cariogenic snacks and beverages. A straightforward model to explain behavioral structures incorporates these findings against the background of living in a highly-deprived environment, whereby the allure of more affordable gratifications for self and family is often translated in the form of tokens such as junk food.

Patients' perspectives of a multifaceted intervention with a focus on technology: a qualitative analysis.

PubMed

Lambert-Kerzner, Anne; Havranek, Edward P; Plomondon, Mary E; Albright, Karen; Moore, Ashley; Gryniewicz, Kelsey; Magid, David; Ho, P Michael

2010-11-01

Few studies have investigated the effectiveness of multifaceted interventions from the study participants' perspective. We conducted qualitative interviews to understand patients' experiences with a multifaceted blood pressure (BP) control intervention involving interactive voice response technology, home BP monitoring, and pharmacist-led BP management. In the randomized study, the intervention resulted in clinically significant decreases in BP. We used insights generated from in-depth interviews from all study participants randomly assigned to the multifaceted intervention or usual care (n=146) to create a model explaining the observed improvements in health behavior and clinical outcomes. The data were analyzed using qualitative content analysis methods and consultative and reflexive team analysis. Six explanatory factors emerged from the patients' interviews: (1) improved relationships with medical personnel; (2) increased knowledge of hypertension; (3) increased participation in their health care and personal empowerment; (4) greater understanding of the impact of health behavior on BP; (5) high satisfaction with technology used in the intervention; and, for some patients, (6) increased health care utilization. Eighty-six percent of the intervention patients and 62% of the usual care patients stated that study participation had a positive effect on them. Of those expressing a positive effect, 68% (intervention) and 55% (usual care) reached their systolic BP goal. Establishing bidirectional conversations between patients and providers is a key element of successful hypertension management. Home BP monitoring coupled with interactive voice response technology reporting facilitates such conversations.

Determinants of energy efficiency across countries

NASA Astrophysics Data System (ADS)

Yao, Guolin

With economic development, environmental concerns become more important. Economies cannot be developed without energy consumption, which is the major source of greenhouse gas emissions. Higher energy efficiency is one means of reducing emissions, but what determines energy efficiency? In this research we attempt to find answers to this question by using cross-sectional country data; that is, we examine a wide range of possible determinants of energy efficiency at the country level in an attempt to find the most important causal factors. All countries are divided into three income groups: high-income countries, middle-income countries, and low-income countries. Energy intensity is used as a measurement of energy efficiency. All independent variables belong to two categories: quantitative and qualitative. Quantitative variables are measures of the economic conditions, development indicators and energy usage situations. Qualitative variables mainly measure political, societal and economic strengths of a country. The three income groups have different economic and energy attributes. Each group has different sets of variables to explain energy efficiency. Energy prices and winter temperature are both important in high-income and middle-income countries. No qualitative variables appear in the model of high-income countries. Basic economic factors, such as institutions, political stability, urbanization level, population density, are important in low-income countries. Besides similar variables, such as macroeconomic stability and index of rule of law, the hydroelectricity share in total electric generation is also a driver of energy efficiency in middle-income countries. These variables have different policy implications for each group of countries.

Mobile computing acceptance factors in the healthcare industry: a structural equation model.

PubMed

Wu, Jen-Her; Wang, Shu-Ching; Lin, Li-Min

2007-01-01

This paper presents a revised technology acceptance model to examine what determines mobile healthcare systems (MHS) acceptance by healthcare professionals. Conformation factor analysis was performed to test the reliability and validity of the measurement model. The structural equation modeling technique was used to evaluate the causal model. The results indicated that compatibility, perceived usefulness and perceived ease of use significantly affected healthcare professional behavioral intent. MHS self-efficacy had strong indirect impact on healthcare professional behavioral intent through the mediators of perceived usefulness and perceived ease of use. Yet, the hypotheses for technical support and training effects on the perceived usefulness and perceived ease of use were not supported. This paper provides initial insights into factors that are likely to be significant antecedents of planning and implementing mobile healthcare to enhance professionals' MHS acceptance. The proposed model variables explained 70% of the variance in behavioral intention to use MHS; further study is needed to explore extra significant antecedents of new IT/IS acceptance for mobile healthcare. Such as privacy and security issue, system and information quality, limitations of mobile devices; the above may be other interesting factors for implementing mobile healthcare and could be conducted by qualitative research.

Simulating the Past, Present and Future of the Upper Troposphere and Lower Stratosphere

NASA Astrophysics Data System (ADS)

Gettelman, Andrew; Hegglin, Michaela

2010-05-01

A comprehensive assessment of coupled chemistry climate model (CCM) performance in the upper troposphere and lower stratosphere has been conducted with 18 models. Both qualitative and quantitative comparisons of model representation of UTLS dynamical, radiative and chemical structure have been conducted, using a collection of quantitative grading techniques. The models are able to reproduce the observed climatology of dynamical, radiative and chemical structure in the tropical and extratropical UTLS, despite relatively coarse vertical and horizontal resolution. Diagnostics of the Tropical Tropopause Layer (TTL), Tropopause Inversion Layer (TIL) and Extra-tropical Transition Layer (ExTL) are analyzed. The results provide new insight into the key processes that govern the dynamics and transport in the tropics and extra-tropicsa. The presentation will explain how models are able to reproduce key features of the UTLS, what features they do not reproduce, and why. Model trends over the historical period are also assessed and interannual variability is included in the metrics. Finally, key trends in the UTLS for the future with a given halogen and greenhouse gas scenario are presented, indicating significant changes in tropopause height and temperature, as well as UTLS ozone concentrations in the 21st century due to climate change and ozone recovery.

Rate/state Coulomb stress transfer model for the CSEP Japan seismicity forecast

NASA Astrophysics Data System (ADS)

Toda, Shinji; Enescu, Bogdan

2011-03-01

Numerous studies retrospectively found that seismicity rate jumps (drops) by coseismic Coulomb stress increase (decrease). The Collaboratory for the Study of Earthquake Prediction (CSEP) instead provides us an opportunity for prospective testing of the Coulomb hypothesis. Here we adapt our stress transfer model incorporating rate and state dependent friction law to the CSEP Japan seismicity forecast. We demonstrate how to compute the forecast rates of large shocks in 2009 using the large earthquakes during the past 120 years. The time dependent impact of the coseismic stress perturbations explains qualitatively well the occurrence of the recent moderate size shocks. Such ability is partly similar to that of statistical earthquake clustering models. However, our model differs from them as follows: the off-fault aftershock zones can be simulated using finite fault sources; the regional areal patterns of triggered seismicity are modified by the dominant mechanisms of the potential sources; the imparted stresses due to large earthquakes produce stress shadows that lead to a reduction of the forecasted number of earthquakes. Although the model relies on several unknown parameters, it is the first physics based model submitted to the CSEP Japan test center and has the potential to be tuned for short-term earthquake forecasts.

Solidarity and ambivalence: comparing two perspectives on intergenerational relations using longitudinal panel data.

PubMed

Hogerbrugge, Martijn J A; Komter, Aafke E

2012-05-01

Research on family relations has extensively used the intergenerational solidarity model proposed by Bengtson and colleagues. Recently, the relevance of this model for explaining changes in family relations has been questioned, and the concept of intergenerational ambivalence has been proposed as a relevant addition to the model, supposedly acting as a catalyst, and thus serving as an explanation for changes in family relations. This study tests both the viability of the intergenerational solidarity model and the hypothesized effect of ambivalence employing longitudinal data. We use data from 2 waves of the Netherlands' Kinship Panel Study on parent-adult child relationships to estimate latent variable structural equation models. Affection, association, and support between family members are core, mutually reinforcing dimensions of solidarity. The hypothesis that ambivalence is a catalyst for change in family relations was not confirmed. Adding conflict separately revealed that it only affects the core solidarity dimensions but is itself, like normative and structural solidarity, not influenced by them. The relevance of the concept of intergenerational ambivalence for studying changes in family relations can be questioned. The viability of the intergenerational solidarity model is, however, confirmed. The concept of intergenerational ambivalence might be further explored in qualitative studies on family change.

Fourier power, subjective distance, and object categories all provide plausible models of BOLD responses in scene-selective visual areas

PubMed Central

Lescroart, Mark D.; Stansbury, Dustin E.; Gallant, Jack L.

2015-01-01

Perception of natural visual scenes activates several functional areas in the human brain, including the Parahippocampal Place Area (PPA), Retrosplenial Complex (RSC), and the Occipital Place Area (OPA). It is currently unclear what specific scene-related features are represented in these areas. Previous studies have suggested that PPA, RSC, and/or OPA might represent at least three qualitatively different classes of features: (1) 2D features related to Fourier power; (2) 3D spatial features such as the distance to objects in a scene; or (3) abstract features such as the categories of objects in a scene. To determine which of these hypotheses best describes the visual representation in scene-selective areas, we applied voxel-wise modeling (VM) to BOLD fMRI responses elicited by a set of 1386 images of natural scenes. VM provides an efficient method for testing competing hypotheses by comparing predictions of brain activity based on encoding models that instantiate each hypothesis. Here we evaluated three different encoding models that instantiate each of the three hypotheses listed above. We used linear regression to fit each encoding model to the fMRI data recorded from each voxel, and we evaluated each fit model by estimating the amount of variance it predicted in a withheld portion of the data set. We found that voxel-wise models based on Fourier power or the subjective distance to objects in each scene predicted much of the variance predicted by a model based on object categories. Furthermore, the response variance explained by these three models is largely shared, and the individual models explain little unique variance in responses. Based on an evaluation of previous studies and the data we present here, we conclude that there is currently no good basis to favor any one of the three alternative hypotheses about visual representation in scene-selective areas. We offer suggestions for further studies that may help resolve this issue. PMID:26594164

Obstacles to adherence in living with type-2 diabetes: an international qualitative study using meta-ethnography (EUROBSTACLE).

PubMed

Vermeire, Etienne; Hearnshaw, Hilary; Rätsep, Anneli; Levasseur, Gwenola; Petek, Davorina; van Dam, Henk; van der Horst, Frans; Vinter-Repalust, Nevenka; Wens, Johan; Dale, Jeremy; Van Royen, Paul

2007-02-01

Quantitative studies failed to determine variables which consistently explain adherence or non-adherence to treatment recommendations. Qualitative studies identified issues such as the quality of the health provider-health receiver relationship and the patient's health beliefs. According to these findings, 39 focus groups of 246 people living with type-2 diabetes were conducted in seven European countries, assessing health beliefs, communication with caregivers and problems encountered in adhering to treatment regimens. Meta-ethnography was later applied to make a qualitative meta-analysis. Obstacles to adherence are common across countries, and seem to be related less to issues of the health-care system and more to patient's knowledge about diabetes, beliefs and attitudes and the relationship with health-care professionals. The resulting key themes are course of diabetes, information, person and context, body awareness and relationship with the health care provider. Meta-ethnography is a feasible tool for the meta-analysis of multilingual qualitative data and leads to a richer account.

[Quantitative and qualitative research methods, can they coexist yet?].

PubMed

Hunt, Elena; Lavoie, Anne-Marise

2011-06-01

Qualitative design is gaining ground in Nursing research. In spite of a relative progress however, the evidence based practice movement continues to dominate and to underline the exclusive value of quantitative design (particularly that of randomized clinical trials) for clinical decision making. In the actual context convenient to those in power making utilitarian decisions on one hand, and facing nursing criticism of the establishment in favor of qualitative research on the other hand, it is difficult to chose a practical and ethical path that values the nursing role within the health care system, keeping us committed to quality care and maintaining researcher's integrity. Both qualitative and quantitative methods have advantages and disadvantages, and clearly, none of them can, by itself, capture, describe and explain reality adequately. Therefore, a balance between the two methods is needed. Researchers bare responsibility to society and science, and they should opt for the appropriate design susceptible to answering the research question, not promote the design favored by the research funding distributors.

Identification of Key Beliefs Explaining Male Circumcision Motivation Among Adolescent Boys in Zimbabwe: Targets for Behavior Change Communication.

PubMed

Kasprzyk, Danuta; Tshimanga, Mufuta; Hamilton, Deven T; Gorn, Gerald J; Montaño, Daniel E

2018-02-01

Male circumcision (MC) significantly reduces HIV acquisition among men, leading WHO/UNAIDS to recommend high HIV and low MC prevalence countries circumcise 80% of adolescents and men age 15-49. Despite significant investment to increase MC capacity only 27% of the goal has been achieved in Zimbabwe. To increase adoption, research to create evidence-based messages is greatly needed. The Integrated Behavioral Model (IBM) was used to investigate factors affecting MC motivation among adolescents. Based on qualitative elicitation study results a survey was designed and administered to a representative sample of 802 adolescent boys aged 13-17 in two urban and two rural areas in Zimbabwe. Multiple regression analysis found all six IBM constructs (2 attitude, 2 social influence, 2 personal agency) significantly explained MC intention (R 2  = 0.55). Stepwise regression analysis of beliefs underlying each IBM belief-based construct found 9 behavioral, 6 injunctive norm, 2 descriptive norm, 5 efficacy, and 8 control beliefs significantly explained MC intention. A final stepwise regression of all the significant IBM construct beliefs identified 12 key beliefs best explaining intention. Similar analyses were carried out with subgroups of adolescents by urban-rural and age. Different sets of behavioral, normative, efficacy, and control beliefs were significant for each sub-group. This study demonstrates the application of theory-driven research to identify evidence-based targets for the design of effective MC messages for interventions to increase adolescents' motivation. Incorporating these findings into communication campaigns is likely to improve demand for MC.

Speech motor development: Integrating muscles, movements, and linguistic units.

PubMed

Smith, Anne

2006-01-01

A fundamental problem for those interested in human communication is to determine how ideas and the various units of language structure are communicated through speaking. The physiological concepts involved in the control of muscle contraction and movement are theoretically distant from the processing levels and units postulated to exist in language production models. A review of the literature on adult speakers suggests that they engage complex, parallel processes involving many units, including sentence, phrase, syllable, and phoneme levels. Infants must develop multilayered interactions among language and motor systems. This discussion describes recent studies of speech motor performance relative to varying linguistic goals during the childhood, teenage, and young adult years. Studies of the developing interactions between speech motor and language systems reveal both qualitative and quantitative differences between the developing and the mature systems. These studies provide an experimental basis for a more comprehensive theoretical account of how mappings between units of language and units of action are formed and how they function. Readers will be able to: (1) understand the theoretical differences between models of speech motor control and models of language processing, as well as the nature of the concepts used in the two different kinds of models, (2) explain the concept of coarticulation and state why this phenomenon has confounded attempts to determine the role of linguistic units, such as syllables and phonemes, in speech production, (3) describe the development of speech motor performance skills and specify quantitative and qualitative differences between speech motor performance in children and adults, and (4) describe experimental methods that allow scientists to study speech and limb motor control, as well as compare units of action used to study non-speech and speech movements.

Weaving a Stronger Fabric for Improved Outcomes

ERIC Educational Resources Information Center

Lobry de Bruyn, Lisa; Prior, Julian; Lenehan, Jo

2014-01-01

Purpose: To explain how training and education events (TEEs) can be designed to increase the likelihood of achieving behavioural objectives. Approach: The approach combined both a quantitative review of evaluation surveys undertaken at the time of the TEE, and qualitative telephone interviews with selected attendees (2025% of the total population…

Exploring a Taboo of Cultural Reproduction

ERIC Educational Resources Information Center

Holligan, Chris

2018-01-01

Cultural reproduction is rarely, if ever, theorised through clandestine practices of sexual offending by teachers in the gendered hierarchies of state schools. Drawing upon Freedom of Information requests and other official qualitative data provided by a U.K. teaching council, this article endeavours to explain the form of a gendered cultural…

Communication Is Key: Unpacking "Use of Assessment Results to Improve Student Learning"

ERIC Educational Resources Information Center

Smith, Kristen L.; Good, Megan Rodgers; Sanchez, Elizabeth Hawk; Fulcher, Keston H.

2015-01-01

Although higher education institutions often engage in assessment practices, use of assessment results to improve student learning is rare (Blaich & Wise, 2011). We surmised that this rarity could be partially explained by unclear communication regarding what "use of results" means. The current study qualitatively investigated how…

The Divided Self: The Double Consciousness of Faculty of Color in Community Colleges

ERIC Educational Resources Information Center

Levin, John S.; Walker, Laurencia; Haberler, Zachary; Jackson-Boothby, Adam

2013-01-01

Through qualitative field methods research addressing faculty of color in four California community colleges, this investigation examines and explains faculty experiences and professional sense making. By combining critical race theory with social identity theory, our perspective underlines the potential social and ethnic identity conflicts…

Enrollment Trends at University of Alaska Community Campuses

ERIC Educational Resources Information Center

Goldsmith, Scott; Hill, Alexandra; Killorin, Mary

2005-01-01

In this report, Institute of Social and Economic Research, University of Alaska Anchorage, investigated the factors that explain change over time in enrollments and credit hours (participation) at the community campuses of the University of Alaska using both quantitative and qualitative methods. Sections include: (1) Background; (2) Factors…

Detecting Low Incidents Effects: The Value of Mixed Methods Research Designs in Low-N Studies

ERIC Educational Resources Information Center

Newman, Isadore; Ridenour, Carolyn S.; Newman, Carole; Smith, Shannon; Brown, Russell C.

2013-01-01

Many important educational situations such as traumatic brain injury among preschoolers, school gun violence, preadolescent eating disorders, and adolescent suicide happen relatively infrequently. In this article, the authors explain why mixed methods research designs offer more meaningful empirical results than do qualitative or quantitative…

Women's Experiences in the Engineering Laboratory in Japan

ERIC Educational Resources Information Center

Hosaka, Masako

2014-01-01

This qualitative study aims to examine Japanese women undergraduate engineering students' experiences of interacting with departmental peers of the same year in the laboratory setting by using interview data of 32 final-year students at two modestly selective national universities in Japan. Expectation state theory that explains unequal…

Persistence Factors of First-Generation Learners

ERIC Educational Resources Information Center

Braswell, Tawanda M.

2010-01-01

This dissertation utilized a qualitative narrative case study method to explore the unknown factors and elements of perseverance in spite of adversity and crisis. The study documented the lives of five African American women in order to describe, understand, and explain the central research question of how and why some first-generation learners…

VoiceThread: A Useful Program Evaluation Tool

ERIC Educational Resources Information Center

Mott, Rebecca

2018-01-01

With today's technology, Extension professionals have a variety of tools available for program evaluation. This article describes an innovative platform called VoiceThread that has been used in many classrooms but also is useful for conducting virtual focus group research. I explain how this tool can be used to collect qualitative participant…

Indigenous Gambling Motivations, Behaviour and Consequences in Northern New South Wales, Australia

ERIC Educational Resources Information Center

Breen, Helen M.; Hing, Nerilee; Gordon, Ashley

2011-01-01

Against a background of public health, we sought to examine and explain gambling behaviours, motivations and consequences of Indigenous Australians in northern New South Wales. Adhering to national Aboriginal and ethical guidelines and using qualitative methods, 169 Indigenous Australians were interviewed individually and in small groups using…

Multiple Methodologies: Using Community-Based Participatory Research and Decolonizing Methodologies in Kenya

ERIC Educational Resources Information Center

Elder, Brent C.; Odoyo, Kenneth O.

2018-01-01

In this project, we examined the development of a sustainable inclusive education system in western Kenya by combining community-based participatory research (CBPR) and decolonizing methodologies. Through three cycles of qualitative interviews with stakeholders in inclusive education, participants explained what they saw as foundational components…

The Effects of Empowering Teachers to Become Leaders through Collaboration

ERIC Educational Resources Information Center

Geraghty, Jennifer

2016-01-01

The intent of this qualitative research study had two purposes. One, to describe and explain the perceptions of elementary school teachers through their participation in a Professional Learning Community, as defined by DuFour, DuFour, Eaker & Many (2010). This research was initiated with elementary education teachers, grades kindergarten…

Too Much Like Thinking to Be Less Than Thought.

ERIC Educational Resources Information Center

Metheny, Eleanor

This speech discusses concrete entities and abstract phenomena--focusing especially on the ideas of Plato and Aristotle. The author first explains that, according to Plato and Aristotle, there is a qualitative difference between things classified as concrete and those labeled abstract. She then questions whether there really is a difference…

Positive Workplace Dynamics: A Qualitative Exploration of Exceptional Performance in Community College Units

ERIC Educational Resources Information Center

Stapleton, R. Michael

2013-01-01

This companion dissertation reports the findings of applied case study research on four community college organizational units that consistently meet or exceed standard performance measures. In addition, prior ample evidence confirmed that performance extended significantly beyond what might be explained by available tangible resources alone. The…

Oral Health Promotion in Schools: Rationale and Evaluation

ERIC Educational Resources Information Center

Kizito, Alex; Caitlin, Meredith; Wang, Yili; Kasangaki, Arabat; Macnab, Andrew J.

2014-01-01

Purpose: The purpose of this paper is to explain the rationale and potential for the WHO health promoting schools (HPS) to improve children's oral health, and describe validated quantitative methodologies and qualitative approaches to measure program impact. Design/Methodology/Approach: Critical discussion of the impact of poor oral health and…

Determinants of Evidence Use in Academic Librarian Decision Making

ERIC Educational Resources Information Center

Koufogiannakis, Denise

2015-01-01

The objective of this qualitative study was to identify and explain challenges encountered by academic librarians when trying to incorporate evidence into their practice. The findings resulted in the identification of five main determinants that act as either obstacles or enablers of evidence use. The identification of these determinants provide…

A View from Somewhere: Explaining the Paradigms of Educational Research

ERIC Educational Resources Information Center

Alexander, Hanan A.

2006-01-01

In this paper I ask how educational researchers can believe the subjective perceptions of qualitative participant-observers given the concern for objectivity and generalisability of experimental research in the behavioural and social sciences. I critique the most common answer to this question within the educational research community, which…

Education Technology Services at Indiana University: A Case Study.

ERIC Educational Resources Information Center

Bichelmeyer, B. A.; Hara, Noriko; Yi, Jessi; Dennen, Vanessa; Avers, Dale; Tzeng, Jeng-Yi

1998-01-01

This paper, based on a qualitative research study, describes the technology resources available in the Indiana University School of Education, explains the range of services provided by Education Technology Services (ETS), documents the organizational structure of ETS, and describes the key processes and culture of ETS. (Author/AEF)

A General Critical Discourse Analysis Framework for Educational Research

ERIC Educational Resources Information Center

Mullet, Dianna R.

2018-01-01

Critical discourse analysis (CDA) is a qualitative analytical approach for critically describing, interpreting, and explaining the ways in which discourses construct, maintain, and legitimize social inequalities. CDA rests on the notion that the way we use language is purposeful, regardless of whether discursive choices are conscious or…

An Ethnographic Case Study on the Phenomena of Blended Learning Teachers

ERIC Educational Resources Information Center

Tiell, Lauren Renae

2017-01-01

This study determined the teacher-perceived experiences within the blended learning environment to fill a void in previous data. The three research questions defined blended learning, explained strengths and challenges, and provided feedback on teaching programs. This qualitative case study used an ethnographic framework through interviews,…

Hydrologic connectivity and threshold behavior of hillslopes with fragipans and soil pipe networks

USDA-ARS?s Scientific Manuscript database

Many concepts have been proposed to explain hydrologic connectivity of hillslopes with streams. Hydrologic connectivity is most often defined by qualitative assessment of spatial patterns in perched water tables or soil moisture on hillslopes without a direct linkage of the connection of water flow ...

Gender bias in hospital leadership: a qualitative study on the experiences of women CEOs.

PubMed

Soklaridis, Sophie; Kuper, Ayelet; Whitehead, Cynthia R; Ferguson, Genevieve; Taylor, Valerie H; Zahn, Catherine

2017-04-10

Purpose The purpose of this paper is to examine the experiences of gender bias among women hospital CEOs and explore to what these female leaders attribute their success within a male-dominated hospital executive leadership milieu. Design/methodology/approach This qualitative study involved 12 women hospital CEOs from across Ontario, Canada. Purposeful sampling techniques and in-depth qualitative interview methods were used to facilitate discussion around experiences of gender and leadership. Findings Responses fell into two groups: the first group represented the statement "Gender inequality is alive and well". The second group reflected the statement "Gender inequity is not significant, did not happen to me, and things are better now". This group contained a sub-group with no consciousness of systemic discrimination and that claimed having no gendered experiences in their leadership journey. The first group described gender issues in various contexts, from the individual to the systemic. The second group was ambivalent about gender as a factor impacting leadership trajectories. Originality/value Representations of women's leadership have become detached from feminism, with major consequences for women. This study reveals how difficult it is for some women CEOs to identify gender bias. The subtle everyday norms and practices within the workplace make it difficult to name and explain gender bias explicitly and may explain the challenges in understanding how it might affect a woman's career path.

Complex Dynamics in Nonequilibrium Economics and Chemistry

NASA Astrophysics Data System (ADS)

Wen, Kehong

Complex dynamics provides a new approach in dealing with economic complexity. We study interactively the empirical and theoretical aspects of business cycles. The way of exploring complexity is similar to that in the study of an oscillatory chemical system (BZ system)--a model for modeling complex behavior. We contribute in simulating qualitatively the complex periodic patterns observed from the controlled BZ experiments to narrow the gap between modeling and experiment. The gap between theory and reality is much wider in economics, which involves studies of human expectations and decisions, the essential difference from natural sciences. Our empirical and theoretical studies make substantial progress in closing this gap. With the help from the new development in nonequilibrium physics, i.e., the complex spectral theory, we advance our technique in detecting characteristic time scales from empirical economic data. We obtain correlation resonances, which give oscillating modes with decays for correlation decomposition, from different time series including S&P 500, M2, crude oil spot prices, and GNP. The time scales found are strikingly compatible with business experiences and other studies in business cycles. They reveal the non-Markovian nature of coherent markets. The resonances enhance the evidence of economic chaos obtained by using other tests. The evolving multi-humped distributions produced by the moving-time -window technique reveal the nonequilibrium nature of economic behavior. They reproduce the American economic history of booms and busts. The studies seem to provide a way out of the debate on chaos versus noise and unify the cyclical and stochastic approaches in explaining business fluctuations. Based on these findings and new expectation formulation, we construct a business cycle model which gives qualitatively compatible patterns to those found empirically. The soft-bouncing oscillator model provides a better alternative than the harmonic oscillator or the random walk model as the building block in business cycle theory. The mathematical structure of the model (delay differential equation) is studied analytically and numerically. The research pave the way toward sensible economic forecasting.

Gut feelings as a third track in general practitioners' diagnostic reasoning.

PubMed

Stolper, Erik; Van de Wiel, Margje; Van Royen, Paul; Van Bokhoven, Marloes; Van der Weijden, Trudy; Dinant, Geert Jan

2011-02-01

General practitioners (GPs) are often faced with complicated, vague problems in situations of uncertainty that they have to solve at short notice. In such situations, gut feelings seem to play a substantial role in their diagnostic process. Qualitative research distinguished a sense of alarm and a sense of reassurance. However, not every GP trusted their gut feelings, since a scientific explanation is lacking. This paper explains how gut feelings arise and function in GPs' diagnostic reasoning. The paper reviews literature from medical, psychological and neuroscientific perspectives. Gut feelings in general practice are based on the interaction between patient information and a GP's knowledge and experience. This is visualized in a knowledge-based model of GPs' diagnostic reasoning emphasizing that this complex task combines analytical and non-analytical cognitive processes. The model integrates the two well-known diagnostic reasoning tracks of medical decision-making and medical problem-solving, and adds gut feelings as a third track. Analytical and non-analytical diagnostic reasoning interacts continuously, and GPs use elements of all three tracks, depending on the task and the situation. In this dual process theory, gut feelings emerge as a consequence of non-analytical processing of the available information and knowledge, either reassuring GPs or alerting them that something is wrong and action is required. The role of affect as a heuristic within the physician's knowledge network explains how gut feelings may help GPs to navigate in a mostly efficient way in the often complex and uncertain diagnostic situations of general practice. Emotion research and neuroscientific data support the unmistakable role of affect in the process of making decisions and explain the bodily sensation of gut feelings.The implications for health care practice and medical education are discussed.

Three-dimensional structural modelling and calculation of electrostatic potentials of HLA Bw4 and Bw6 epitopes to explain the molecular basis for alloantibody binding: toward predicting HLA antigenicity and immunogenicity.

PubMed

Mallon, Dermot H; Bradley, J Andrew; Winn, Peter J; Taylor, Craig J; Kosmoliaptsis, Vasilis

2015-02-01

We have previously shown that qualitative assessment of surface electrostatic potential of HLA class I molecules helps explain serological patterns of alloantibody binding. We have now used a novel computational approach to quantitate differences in surface electrostatic potential of HLA B-cell epitopes and applied this to explain HLA Bw4 and Bw6 antigenicity. Protein structure models of HLA class I alleles expressing either the Bw4 or Bw6 epitope (defined by sequence motifs at positions 77 to 83) were generated using comparative structure prediction. The electrostatic potential in 3-dimensional space encompassing the Bw4/Bw6 epitope was computed by solving the Poisson-Boltzmann equation and quantitatively compared in a pairwise, all-versus-all fashion to produce distance matrices that cluster epitopes with similar electrostatics properties. Quantitative comparison of surface electrostatic potential at the carboxyl terminal of the α1-helix of HLA class I alleles, corresponding to amino acid sequence motif 77 to 83, produced clustering of HLA molecules in 3 principal groups according to Bw4 or Bw6 epitope expression. Remarkably, quantitative differences in electrostatic potential reflected known patterns of serological reactivity better than Bw4/Bw6 amino acid sequence motifs. Quantitative assessment of epitope electrostatic potential allowed the impact of known amino acid substitutions (HLA-B*07:02 R79G, R82L, G83R) that are critical for antibody binding to be predicted. We describe a novel approach for quantitating differences in HLA B-cell epitope electrostatic potential. Proof of principle is provided that this approach enables better assessment of HLA epitope antigenicity than amino acid sequence data alone, and it may allow prediction of HLA immunogenicity.

Gut Feelings as a Third Track in General Practitioners’ Diagnostic Reasoning

PubMed Central

Van de Wiel, Margje; Van Royen, Paul; Van Bokhoven, Marloes; Van der Weijden, Trudy; Dinant, Geert Jan

2010-01-01

Background General practitioners (GPs) are often faced with complicated, vague problems in situations of uncertainty that they have to solve at short notice. In such situations, gut feelings seem to play a substantial role in their diagnostic process. Qualitative research distinguished a sense of alarm and a sense of reassurance. However, not every GP trusted their gut feelings, since a scientific explanation is lacking. Objective This paper explains how gut feelings arise and function in GPs’ diagnostic reasoning. Approach The paper reviews literature from medical, psychological and neuroscientific perspectives. Conclusions Gut feelings in general practice are based on the interaction between patient information and a GP’s knowledge and experience. This is visualized in a knowledge-based model of GPs’ diagnostic reasoning emphasizing that this complex task combines analytical and non-analytical cognitive processes. The model integrates the two well-known diagnostic reasoning tracks of medical decision-making and medical problem-solving, and adds gut feelings as a third track. Analytical and non-analytical diagnostic reasoning interacts continuously, and GPs use elements of all three tracks, depending on the task and the situation. In this dual process theory, gut feelings emerge as a consequence of non-analytical processing of the available information and knowledge, either reassuring GPs or alerting them that something is wrong and action is required. The role of affect as a heuristic within the physician’s knowledge network explains how gut feelings may help GPs to navigate in a mostly efficient way in the often complex and uncertain diagnostic situations of general practice. Emotion research and neuroscientific data support the unmistakable role of affect in the process of making decisions and explain the bodily sensation of gut feelings.The implications for health care practice and medical education are discussed. PMID:20967509

What explains between-school differences in rates of sexual experience?

PubMed Central

Henderson, Marion; Butcher, Isabella; Wight, Daniel; Williamson, Lisa; Raab, Gillian

2008-01-01

Background Schools have the potential to influence their pupils' behaviour through the school's social organisation and culture, as well as through the formal curriculum. This paper provides the first attempt to explain the differences between schools in rates of reported heterosexual sexual experience amongst 15 and 16 year olds. It first examined whether variations in rates of sexual experience remained after controlling for the known predictors of sexual activity. It then examined whether these residuals, or 'school effects', were attributable to processes within the school, or were more likely to reflect characteristics of the neighbourhood. Methods Longitudinal survey data from 4,926 pupils in 24 Scottish schools were linked to qualitative and quantitative data on school processes including quality of relationships (staff-pupil, etc), classroom discipline, organisation of Personal and Social Education, school appearance and pupil morale. Multi-level modelling was used to test a range of models and the resulting 'school effects' were then interpreted using the process data. Results Overall, 42% of girls and 33% of boys reported experience of sexual intercourse, with rates by school ranging from 23% to 61%. When individual socio-economic and socio-cultural factors were taken into account the school variation dropped sharply, though pupils' attitudes and aspirations had little effect. There was very little correlation between boys' and girls' rates of sexual experience by school, after controlling for known predictors of sexual activity. Girls were more influenced by individual socio-economic factors than boys. School-level socio-economic factors were predictive even after taking account of individual socio-cultural factors, suggesting that the wider socio-economic environment further influenced young people's sexual experience. Conclusion Importantly, school processes did not explain the variation between schools in sexual experience. Rather, the variation may have been due to neighbourhood culture. PMID:18261205

Assigning poetry reading as a way of introducing students to qualitative data analysis.

PubMed

Raingruber, Bonnie

2009-08-01

The aim of the paper is to explain how poetry reading can be used to teach interpretive analysis of qualitative data. A number of studies were located in the nursing literature that focused on using poetry to help students develop empathy for patients, to teach students to reflect on their own practice, and to assist them in developing self-understanding. No studies were found that described the use of poetry reading as a way of teaching the skill of interpretive analysis. There are, however, a number of parallels between the principles of poetry reading and qualitative analysis that suggest that this method of teaching would be successful. International papers published on PubMed, Medline, and CINAHL were reviewed to identify challenges facing educators and ways of teaching the process of qualitative data analysis using poetry reading. Using poetry reading to teach skills of qualitative data analysis helps motivate students, cultivates a reflective mindset, and develops the skill of working as a member of an interpretive group. Framing interpretive work as being like reading poetry helps students pick up more quickly on the art that is a major component of the work. This approach also helps students learn the importance of cultural and contextual particulars as they begin analyzing qualitative data. Using poetry reading to introduce students to the complex skill of qualitative data analysis is an effective pedagogical strategy.

Teacher challenges, perceptions, and use of science models in middle school classrooms about climate, weather, and energy concepts

NASA Astrophysics Data System (ADS)

Yarker, Morgan Brown

Research suggests that scientific models and modeling should be topics covered in K-12 classrooms as part of a comprehensive science curriculum. It is especially important when talking about topics in weather and climate, where computer and forecast models are the center of attention. There are several approaches to model based inquiry, but it can be argued, theoretically, that science models can be effectively implemented into any approach to inquiry if they are utilized appropriately. Yet, it remains to be explored how science models are actually implemented in classrooms. This study qualitatively looks at three middle school science teachers' use of science models with various approaches to inquiry during their weather and climate units. Results indicate that the teacher who used the most elements of inquiry used models in a way that aligned best with the theoretical framework than the teachers who used fewer elements of inquiry. The theoretical framework compares an approach to argument-based inquiry to model-based inquiry, which argues that the approaches are essentially identical, so teachers who use inquiry should be able to apply model-based inquiry using the same approach. However, none of the teachers in this study had a complete understanding of the role models play in authentic science inquiry, therefore students were not explicitly exposed to the ideas that models can be used to make predictions about, and are representations of, a natural phenomenon. Rather, models were explicitly used to explain concepts to students or have students explain concepts to the teacher or to each other. Additionally, models were used as a focal point for conversation between students, usually as they were creating, modifying, or using models. Teachers were not observed asking students to evaluate models. Since science models are an important aspect of understanding science, it is important that teachers not only know how to implement models into an inquiry environment, but also understand the characteristics of science models so that they can explicitly teach the concept of modeling to students. This study suggests that better pre-service and in-service teacher education is needed to prepare students to teach about science models effectively.

Standards for reporting qualitative research: a synthesis of recommendations.

PubMed

O'Brien, Bridget C; Harris, Ilene B; Beckman, Thomas J; Reed, Darcy A; Cook, David A

2014-09-01

Standards for reporting exist for many types of quantitative research, but currently none exist for the broad spectrum of qualitative research. The purpose of the present study was to formulate and define standards for reporting qualitative research while preserving the requisite flexibility to accommodate various paradigms, approaches, and methods. The authors identified guidelines, reporting standards, and critical appraisal criteria for qualitative research by searching PubMed, Web of Science, and Google through July 2013; reviewing the reference lists of retrieved sources; and contacting experts. Specifically, two authors reviewed a sample of sources to generate an initial set of items that were potentially important in reporting qualitative research. Through an iterative process of reviewing sources, modifying the set of items, and coding all sources for items, the authors prepared a near-final list of items and descriptions and sent this list to five external reviewers for feedback. The final items and descriptions included in the reporting standards reflect this feedback. The Standards for Reporting Qualitative Research (SRQR) consists of 21 items. The authors define and explain key elements of each item and provide examples from recently published articles to illustrate ways in which the standards can be met. The SRQR aims to improve the transparency of all aspects of qualitative research by providing clear standards for reporting qualitative research. These standards will assist authors during manuscript preparation, editors and reviewers in evaluating a manuscript for potential publication, and readers when critically appraising, applying, and synthesizing study findings.

Qualitative research: a review of methods with use of examples from the total knee replacement literature.

PubMed

Beaton, Dorcas E; Clark, Jocalyn P

2009-05-01

Qualitative research is a useful approach to explore perplexing or complicated clinical situations. Since 1996, at least fifteen qualitative studies in the area of total knee replacement alone were found. Qualitative studies overcome the limits of quantitative work because they can explicate deeper meaning and complexity associated with questions such as why patients decline joint replacement surgery, why they do not adhere to pain medication and exercise regimens, how they manage in the postoperative period, and why providers do not always provide evidence-based care. In this paper, we review the role of qualitative methods in orthopaedic research, using knee osteoarthritis as an illustrative example. Qualitative research questions tend to be inductive, and the stance of the investigator is relevant and explicitly acknowledged. Qualitative methodologies include grounded theory, phenomenology, and ethnography and involve gathering opinions and text from individuals or focus groups. The methods are rigorous and take training and time to apply. Analysis of the textual data typically proceeds with the identification, coding, and categorization of patterns in the data for the purpose of generating concepts from within the data. With use of analytic techniques, researchers strive to explain the findings; questions are asked to tease out different levels of meaning, identify new concepts and themes, and permit a deeper interpretation and understanding. Orthopaedic practitioners should consider the use of qualitative research as a tool for exploring the meaning and complexities behind some of the perplexing phenomena that they observe in research findings and clinical practice.

The Dimensionality of Reasoning: Inductive and Deductive Inference can be Explained by a Single Process.

PubMed

Hayes, Brett K; Stephens, Rachel G; Ngo, Jeremy; Dunn, John C

2018-02-01

Three-experiments examined the number of qualitatively different processing dimensions needed to account for inductive and deductive reasoning. In each study, participants were presented with arguments that varied in logical validity and consistency with background knowledge (believability), and evaluated them according to deductive criteria (whether the conclusion was necessarily true given the premises) or inductive criteria (whether the conclusion was plausible given the premises). We examined factors including working memory load (Experiments 1 and 2), individual working memory capacity (Experiments 1 and 2), and decision time (Experiment 3), which according to dual-processing theories, modulate the contribution of heuristic and analytic processes to reasoning. A number of empirical dissociations were found. Argument validity affected deduction more than induction. Argument believability affected induction more than deduction. Lower working memory capacity reduced sensitivity to argument validity and increased sensitivity to argument believability, especially under induction instructions. Reduced decision time led to decreased sensitivity to argument validity. State-trace analyses of each experiment, however, found that only a single underlying dimension was required to explain patterns of inductive and deductive judgments. These results show that the dissociations, which have traditionally been seen as supporting dual-processing models of reasoning, are consistent with a single-process model that assumes a common evidentiary scale for induction and deduction. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Using databases in medical education research: AMEE Guide No. 77.

PubMed

Cleland, Jennifer; Scott, Neil; Harrild, Kirsten; Moffat, Mandy

2013-05-01

This AMEE Guide offers an introduction to the use of databases in medical education research. It is intended for those who are contemplating conducting research in medical education but are new to the field. The Guide is structured around the process of planning your research so that data collection, management and analysis are appropriate for the research question. Throughout we consider contextual possibilities and constraints to educational research using databases, such as the resources available, and provide concrete examples of medical education research to illustrate many points. The first section of the Guide explains the difference between different types of data and classifying data, and addresses the rationale for research using databases in medical education. We explain the difference between qualitative research and qualitative data, the difference between categorical and quantitative data, and the difference types of data which fall into these categories. The Guide reviews the strengths and weaknesses of qualitative and quantitative research. The next section is structured around how to work with quantitative and qualitative databases and provides guidance on the many practicalities of setting up a database. This includes how to organise your database, including anonymising data and coding, as well as preparing and describing your data so it is ready for analysis. The critical matter of the ethics of using databases in medical educational research, including using routinely collected data versus data collected for research purposes, and issues of confidentiality, is discussed. Core to the Guide is drawing out the similarities and differences in working with different types of data and different types of databases. Future AMEE Guides in the research series will address statistical analysis of data in more detail.

Knowledge representation and qualitative simulation of salmon redd functioning. Part I: qualitative modeling and simulation.

PubMed

Guerrin, F; Dumas, J

2001-02-01

This work aims at representing empirical knowledge of freshwater ecologists on the functioning of salmon redds (spawning areas of salmon) and its impact on mortality of early stages. For this, we use Qsim, a qualitative simulator. In this first part, we provide unfamiliar readers with the underlying qualitative differential equation (QDE) ontology of Qsim: representing quantities, qualitative variables, qualitative constraints, QDE structure. Based on a very simple example taken of the salmon redd application, we show how informal biological knowledge may be represented and simulated using an approach that was first intended to analyze qualitatively ordinary differential equations systems. A companion paper (Part II) gives the full description and simulation of the salmon redd qualitative model. This work was part of a project aimed at assessing the impact of the environment on salmon populations dynamics by the use of models of processes acting at different levels: catchment, river, and redds. Only the latter level is dealt with in this paper.

Qualitative studies. Their role in medical research.

PubMed Central

Huston, P.; Rowan, M.

1998-01-01

OBJECTIVE: To define qualitative research in terms of its philosophical roots, the questions it addresses, its methods and analyses, and the type of results it can offer. DATA SOURCES: MEDLINE and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases were searched for the years January 1985 to April 1998. The search strategy consisted of "textword" terms that searched in the "title" field of both databases. Qualitative research and evaluation textbooks in health and the social sciences were also used. QUALITY OF EVIDENCE: The information on qualitative research is based on the most recent and valid evidence from the health and social science fields. MAIN MESSAGE: Qualitative research seeks to understand and interpret personal experience to explain social phenomena, including those related to health. It can address questions that quantitative research cannot, such as why people do not adhere to a treatment regimen or why a certain health care intervention is successful. It uses many methods of data collection, including participant observation, case studies, and interviews, and numerous approaches to data analysis that range from the quasistatistical to the intuitive and inductive. CONCLUSIONS: Qualitative research, a form of research completely different from quantitative research, can provide important insights into health-related phenomena and can enrich further research inquiries. PMID:9839063

A comparison of major petroleum life cycle models | Science ...

EPA Pesticide Factsheets

Many organizations have attempted to develop an accurate well-to-pump life cycle model of petroleum products in order to inform decision makers of the consequences of its use. Our paper studies five of these models, demonstrating the differences in their predictions and attempting to evaluate their data quality. Carbon dioxide well-to-pump emissions for gasoline showed a variation of 35 %, and other pollutants such as ammonia and particulate matter varied up to 100 %. Differences in allocation do not appear to explain differences in predictions. Effects of these deviations on well-to-wheels passenger vehicle and truck transportation life cycle models may be minimal for effects such as global warming potential (6 % spread), but for respiratory effects of criteria pollutants (41 % spread) and other impact categories, they can be significant. A data quality assessment of the models’ documentation revealed real differences between models in temporal and geographic representativeness, completeness, as well as transparency. Stakeholders may need to consider carefully the tradeoffs inherent when selecting a model to conduct life cycle assessments for systems that make heavy use of petroleum products. This is a qualitative and quantitative comparison of petroleum LCA models intended for an expert audience interested in better understanding the data quality of existing petroleum life cycle models and the quantitative differences between these models.

Plasma Reflection in Multigrain Layers of Narrow-Bandgap Semiconductors

NASA Astrophysics Data System (ADS)

Zhukov, N. D.; Shishkin, M. I.; Rokakh, A. G.

2018-04-01

Qualitatively similar spectral characteristics of plasma-resonance reflection in the region of 15-25 μm were obtained for layers of electrodeposited submicron particles of InSb, InAs, and GaAs and plates of these semiconductors ground with M1-grade diamond powder. The most narrow-bandgap semiconductor InSb (intrinsic absorption edge ˜7 μm) is characterized by an absorption band at 2.1-2.3 μm, which is interpreted in terms of the model of optical excitation of electrons coupled by the Coulomb interaction. The spectra of a multigrain layer of chemically deposited PbS nanoparticles (50-70 nm) exhibited absorption maxima at 7, 10, and 17 μm, which can be explained by electron transitions obeying the energy-quantization rules for quantum dots.

Continuous and discontinuous transitions to synchronization.

PubMed

Wang, Chaoqing; Garnier, Nicolas B

2016-11-01

We describe how the transition to synchronization in a system of globally coupled Stuart-Landau oscillators changes from continuous to discontinuous when the nature of the coupling is moved from diffusive to reactive. We explain this drastic qualitative change as resulting from the co-existence of a particular synchronized macrostate together with the trivial incoherent macrostate, in a range of parameter values for which the latter is linearly stable. In contrast to the paradigmatic Kuramoto model, this particular state observed at the synchronization transition contains a finite, non-vanishing number of synchronized oscillators, which results in a discontinuous transition. We consider successively two situations where either a fully synchronized state or a partially synchronized state exists at the transition. Thermodynamic limit and finite size effects are briefly discussed, as well as connections with recently observed discontinuous transitions.

Electronic structure and magnetic properties of the half-metallic ferrimagnet Mn2VAl probed by soft x-ray spectroscopies

NASA Astrophysics Data System (ADS)

Nagai, K.; Fujiwara, H.; Aratani, H.; Fujioka, S.; Yomosa, H.; Nakatani, Y.; Kiss, T.; Sekiyama, A.; Kuroda, F.; Fujii, H.; Oguchi, T.; Tanaka, A.; Miyawaki, J.; Harada, Y.; Takeda, Y.; Saitoh, Y.; Suga, S.; Umetsu, R. Y.

2018-01-01

We have studied the electronic structure of ferrimagnetic Mn2VAl single crystals by means of soft x-ray absorption spectroscopy (XAS), x-ray absorption magnetic circular dichroism (XMCD), and resonant soft x-ray inelastic scattering (RIXS). We have successfully observed the XMCD signals for all the constituent elements. The Mn L2 ,3 XAS and XMCD spectra are reproduced by spectral simulations based on density-functional theory, indicating the itinerant character of the Mn 3 d states. On the other hand, the V 3 d electrons are rather localized since the ionic model can qualitatively explain the V L2 ,3 XAS and XMCD spectra. This picture is consistent with local d d excitations revealed by the V L3 RIXS.

Shaking stack model of ion conduction through the Ca(2+)-activated K+ channel.

PubMed Central

Schumaker, M F

1992-01-01

Motivated by the results of Neyton and Miller (1988. J. Gen. Physiol. 92:549-586), suggesting that the Ca(2+)-activated K+ channel has four high affinity ion binding sites, we propose a physically attractive variant of the single-vacancy conduction mechanism for this channel. Simple analytical expressions for conductance, current, flux ratio exponent, and reversal potential under bi-ionic conditions are found. A set of conductance data are analyzed to determine a realistic range of parameter values. Using these, we find qualitative agreement with a variety of experimental results previously reported in the literature. The exquisite selectivity of the Ca(2+)-activated K+ channel may be explained as a consequence of the concerted motion of the "stack" in the proposed mechanism. PMID:1420923

Long-range Coulomb effect in above-threshold ionization of Ne subject to few-cycle and multicycle laser fields

NASA Astrophysics Data System (ADS)

Xu, SongPo; Quan, Wei; Chen, YongJu; Xiao, ZhiLei; Wang, YanLan; Kang, HuiPeng; Hua, LinQiang; Gong, Cheng; Lai, XuanYang; Liu, XiaoJun; Hao, XiaoLei; Hu, ShiLin; Chen, Jing

2017-06-01

The long-range Coulomb effect (LRCE) is demonstrated experimentally and theoretically by investigating the pulse duration dependence of low-energy structure (LES) in above-threshold ionization of Ne. It is found experimentally that at 800 nm the LES shows itself as a double-hump structure (DHS) in momentum distribution of singly charged ion for Ne, and moreover, this structure is more prominent for multicycle laser fields than for few-cycle cases. This result can be reproduced and explained qualitatively with a semiclassical model and attributed to the paramount role of LRCE. That is to say, after the laser field vanishes, the electrons decelerate while flying away from the core by the long-range tail of Coulomb potential, which eventually makes DHS less notable.

Managing lifestyle change to reduce coronary risk: a synthesis of qualitative research on peoples’ experiences

PubMed Central

2014-01-01

Background Coronary heart disease is an incurable condition. The only approach known to slow its progression is healthy lifestyle change and concordance with cardio-protective medicines. Few people fully succeed in these daily activities so potential health improvements are not fully realised. Little is known about peoples’ experiences of managing lifestyle change. The aim of this study was to synthesise qualitative research to explain how participants make lifestyle change after a cardiac event and explore this within the wider illness experience. Methods A qualitative synthesis was conducted drawing upon the principles of meta-ethnography. Qualitative studies were identified through a systematic search of 7 databases using explicit criteria. Key concepts were identified and translated across studies. Findings were discussed and diagrammed during a series of audiotaped meetings. Results The final synthesis is grounded in findings from 27 studies, with over 500 participants (56% male) across 8 countries. All participants experienced a change in their self-identity from what was ‘familiar’ to ‘unfamiliar’. The transition process involved ‘finding new limits and a life worth living’ , ‘finding support for self’ and ‘finding a new normal’. Analyses of these concepts led to the generation of a third order construct, namely an ongoing process of ‘reassessing past, present and future lives’ as participants considered their changed identity. Participants experienced a strong urge to get back to ‘normal’. Support from family and friends could enable or constrain life change and lifestyle changes. Lifestyle change was but one small part of a wider ‘life’ change that occurred. Conclusions The final synthesis presents an interpretation, not evident in the primary studies, of a person-centred model to explain how lifestyle change is situated within ‘wider’ life changes. The magnitude of individual responses to a changed health status varied. Participants experienced distress as their notion of self identity shifted and emotions that reflected the various stages of the grief process were evident in participants’ accounts. The process of self-managing lifestyle took place through experiential learning; the level of engagement with lifestyle change reflected an individual’s unique view of the balance needed to manage ‘realistic change’ whilst leading to a life that was perceived as ‘worth living’. Findings highlight the importance of providing person centred care that aligns with both psychological and physical dimensions of recovery which are inextricably linked. PMID:25097066

Internet-based medical education: a realist review of what works, for whom and in what circumstances

PubMed Central

2010-01-01

Background Educational courses for doctors and medical students are increasingly offered via the Internet. Despite much research, course developers remain unsure about what (if anything) to offer online and how. Prospective learners lack evidence-based guidance on how to choose between the options on offer. We aimed to produce theory driven criteria to guide the development and evaluation of Internet-based medical courses. Methods Realist review - a qualitative systematic review method whose goal is to identify and explain the interaction between context, mechanism and outcome. We searched 15 electronic databases and references of included articles, seeking to identify theoretical models of how the Internet might support learning from empirical studies which (a) used the Internet to support learning, (b) involved doctors or medical students; and (c) reported a formal evaluation. All study designs and outcomes were considered. Using immersion and interpretation, we tested theories by considering how well they explained the different outcomes achieved in different educational contexts. Results 249 papers met our inclusion criteria. We identified two main theories of the course-in-context that explained variation in learners' satisfaction and outcomes: Davis's Technology Acceptance Model and Laurillard's model of interactive dialogue. Learners were more likely to accept a course if it offered a perceived advantage over available non-Internet alternatives, was easy to use technically, and compatible with their values and norms. 'Interactivity' led to effective learning only if learners were able to enter into a dialogue - with a tutor, fellow students or virtual tutorials - and gain formative feedback. Conclusions Different modes of course delivery suit different learners in different contexts. When designing or choosing an Internet-based course, attention must be given to the fit between its technical attributes and learners' needs and priorities; and to ways of providing meaningful interaction. We offer a preliminary set of questions to aid course developers and learners consider these issues. PMID:20122253

Dielectric properties of calicum and barium-doped strontium titanate

NASA Astrophysics Data System (ADS)

Tung, Li-Chun

Dielectric properties of high quality polycrystalline Ca- and Ba-doped SrTiO3 perovskites are studied by means of dielectric constant, dielectric loss and ferroelectric hysteresis measurements. Low frequency dispersion of the dielectric constant is found to be very small and a simple relaxor model may not be able to explain its dielectric behavior. Relaxation modes are found in these samples, and they are all interpreted as thermally activated Bipolar re-orientation across energy barriers. In Sr1- xCaxTiO3 (x = 0--0.3), two modes are found associated with different relaxation processes, and the concentration dependence implies a competition between these processes. In Sr1-xBa xTiO3 (x = 0--0.25), relaxation modes are found to be related to the structural transitions, and the relaxation modes persist at low doping levels (x < 0.1), where structural ordering is not observed by previous neutron scattering studies. The validity of well-accepted Barret formula is discussed and two of the well-accepted models, anharmonic oscillator model and transverse Ising model, are found to be equivalent. Both of the Ca and Ba systems can be understood qualitatively within the concept of transverse Ising model.

Advances in nowcasting influenza-like illness rates using search query logs

NASA Astrophysics Data System (ADS)

Lampos, Vasileios; Miller, Andrew C.; Crossan, Steve; Stefansen, Christian

2015-08-01

User-generated content can assist epidemiological surveillance in the early detection and prevalence estimation of infectious diseases, such as influenza. Google Flu Trends embodies the first public platform for transforming search queries to indications about the current state of flu in various places all over the world. However, the original model significantly mispredicted influenza-like illness rates in the US during the 2012-13 flu season. In this work, we build on the previous modeling attempt, proposing substantial improvements. Firstly, we investigate the performance of a widely used linear regularized regression solver, known as the Elastic Net. Then, we expand on this model by incorporating the queries selected by the Elastic Net into a nonlinear regression framework, based on a composite Gaussian Process. Finally, we augment the query-only predictions with an autoregressive model, injecting prior knowledge about the disease. We assess predictive performance using five consecutive flu seasons spanning from 2008 to 2013 and qualitatively explain certain shortcomings of the previous approach. Our results indicate that a nonlinear query modeling approach delivers the lowest cumulative nowcasting error, and also suggest that query information significantly improves autoregressive inferences, obtaining state-of-the-art performance.

Investigating the relative permeability behavior of microporosity-rich carbonates and tight sandstones with multiscale pore network models

NASA Astrophysics Data System (ADS)

Bultreys, Tom; Stappen, Jeroen Van; Kock, Tim De; Boever, Wesley De; Boone, Marijn A.; Hoorebeke, Luc Van; Cnudde, Veerle

2016-11-01

The relative permeability behavior of rocks with wide ranges of pore sizes is in many cases still poorly understood and is difficult to model at the pore scale. In this work, we investigate the capillary pressure and relative permeability behavior of three outcrop carbonates and two tight reservoir sandstones with wide, multimodal pore size distributions. To examine how the drainage and imbibition properties of these complex rock types are influenced by the connectivity of macropores to each other and to zones with unresolved small-scale porosity, we apply a previously presented microcomputed-tomography-based multiscale pore network model to these samples. The sensitivity to the properties of the small-scale porosity is studied by performing simulations with different artificial sphere-packing-based networks as a proxy for these pores. Finally, the mixed-wet water-flooding behavior of the samples is investigated, assuming different wettability distributions for the microporosity and macroporosity. While this work is not an attempt to perform predictive modeling, it seeks to qualitatively explain the behavior of the investigated samples and illustrates some of the most recent developments in multiscale pore network modeling.

Tetrahedrality and structural order for hydrophobic interactions in a coarse-grained water model

NASA Astrophysics Data System (ADS)

Chaimovich, Aviel; Shell, M. Scott

2014-02-01

The hydrophobic interaction manifests two separate regimes in terms of size: Small nonpolar bodies exhibit a weak oscillatory force (versus distance) while large nonpolar surfaces exhibit a strong monotonic one. This crossover in hydrophobic behavior is typically explained in terms of water's tetrahedral structure: Its tetrahedrality is enhanced near small solutes and diminished near large planar ones. Here, we demonstrate that water's tetrahedral correlations signal this switch even in a highly simplified, isotropic, "core-softened" water model. For this task, we introduce measures of tetrahedrality based on the angular distribution of water's nearest neighbors. On a quantitative basis, the coarse-grained model of course is only approximate: (1) While greater than simple Lennard-Jones liquids, its bulk tetrahedrality remains lower than that of fully atomic models; and (2) the decay length of the large-scale hydrophobic interaction is less than has been found in experiments. Even so, the qualitative behavior of the model is surprisingly rich and exhibits numerous waterlike hydrophobic behaviors, despite its simplicity. We offer several arguments for the manner in which it should be able to (at least partially) reproduce tetrahedral correlations underlying these effects.

Tetrahedrality and structural order for hydrophobic interactions in a coarse-grained water model.

PubMed

Chaimovich, Aviel; Shell, M Scott

2014-02-01

The hydrophobic interaction manifests two separate regimes in terms of size: Small nonpolar bodies exhibit a weak oscillatory force (versus distance) while large nonpolar surfaces exhibit a strong monotonic one. This crossover in hydrophobic behavior is typically explained in terms of water's tetrahedral structure: Its tetrahedrality is enhanced near small solutes and diminished near large planar ones. Here, we demonstrate that water's tetrahedral correlations signal this switch even in a highly simplified, isotropic, "core-softened" water model. For this task, we introduce measures of tetrahedrality based on the angular distribution of water's nearest neighbors. On a quantitative basis, the coarse-grained model of course is only approximate: (1) While greater than simple Lennard-Jones liquids, its bulk tetrahedrality remains lower than that of fully atomic models; and (2) the decay length of the large-scale hydrophobic interaction is less than has been found in experiments. Even so, the qualitative behavior of the model is surprisingly rich and exhibits numerous waterlike hydrophobic behaviors, despite its simplicity. We offer several arguments for the manner in which it should be able to (at least partially) reproduce tetrahedral correlations underlying these effects.

Advances in nowcasting influenza-like illness rates using search query logs.

PubMed

Lampos, Vasileios; Miller, Andrew C; Crossan, Steve; Stefansen, Christian

2015-08-03

User-generated content can assist epidemiological surveillance in the early detection and prevalence estimation of infectious diseases, such as influenza. Google Flu Trends embodies the first public platform for transforming search queries to indications about the current state of flu in various places all over the world. However, the original model significantly mispredicted influenza-like illness rates in the US during the 2012-13 flu season. In this work, we build on the previous modeling attempt, proposing substantial improvements. Firstly, we investigate the performance of a widely used linear regularized regression solver, known as the Elastic Net. Then, we expand on this model by incorporating the queries selected by the Elastic Net into a nonlinear regression framework, based on a composite Gaussian Process. Finally, we augment the query-only predictions with an autoregressive model, injecting prior knowledge about the disease. We assess predictive performance using five consecutive flu seasons spanning from 2008 to 2013 and qualitatively explain certain shortcomings of the previous approach. Our results indicate that a nonlinear query modeling approach delivers the lowest cumulative nowcasting error, and also suggest that query information significantly improves autoregressive inferences, obtaining state-of-the-art performance.

Inside the Green House "Black Box": Opportunities for High-Quality Clinical Decision Making.

PubMed

Bowers, Barbara; Roberts, Tonya; Nolet, Kimberly; Ryther, Brenda

2016-02-01

To develop a conceptual model that explained common and divergent care processes in Green House (GH) nursing homes with high and low hospital transfer rates. Eighty-four face-to-face, semistructured interviews were conducted with direct care, professional, and administrative staff with knowledge of care processes in six GH organizations in six states. The qualitative grounded theory method was used for data collection and analysis. Data were analyzed using open, axial, and selective coding. Data collection and analysis occurred iteratively. Elements of the GH model created significant opportunities to identify, communicate, and respond to early changes in resident condition. Staff in GH homes with lower hospital transfer rates employed care processes that maximized these opportunities. Staff in GH homes with higher transfer rates failed to maximize, or actively undermined, these opportunities. Variations in how the GH model was implemented across GH homes suggest possible explanations for inconsistencies found in past research on the care outcomes, including hospital transfer rates, in culture change models. The findings further suggest that the details of culture change implementation are important considerations in model replication and policies that create incentives for care improvements. © Health Research and Educational Trust.

A comparison of random draw and locally neutral models for the avifauna of an English woodland.

PubMed

Dolman, Andrew M; Blackburn, Tim M

2004-06-03

Explanations for patterns observed in the structure of local assemblages are frequently sought with reference to interactions between species, and between species and their local environment. However, analyses of null models, where non-interactive local communities are assembled from regional species pools, have demonstrated that much of the structure of local assemblages remains in simulated assemblages where local interactions have been excluded. Here we compare the ability of two null models to reproduce the breeding bird community of Eastern Wood, a 16-hectare woodland in England, UK. A random draw model, in which there is complete annual replacement of the community by immigrants from the regional pool, is compared to a locally neutral community model, in which there are two additional parameters describing the proportion of the community replaced annually (per capita death rate) and the proportion of individuals recruited locally rather than as immigrants from the regional pool. Both the random draw and locally neutral model are capable of reproducing with significant accuracy several features of the observed structure of the annual Eastern Wood breeding bird community, including species relative abundances, species richness and species composition. The two additional parameters present in the neutral model result in a qualitatively more realistic representation of the Eastern Wood breeding bird community, particularly of its dynamics through time. The fact that these parameters can be varied, allows for a close quantitative fit between model and observed communities to be achieved, particularly with respect to annual species richness and species accumulation through time. The presence of additional free parameters does not detract from the qualitative improvement in the model and the neutral model remains a model of local community structure that is null with respect to species differences at the local scale. The ability of this locally neutral model to describe a larger number of woodland bird communities with either little variation in its parameters or with variation explained by features local to the woods themselves (such as the area and isolation of a wood) will be a key subsequent test of its relevance.

A cyclostrophic transformed Eulerian zonal mean model for the middle atmosphere of slowly rotating planets

NASA Astrophysics Data System (ADS)

Li, K. F.; Yao, K.; Taketa, C.; Zhang, X.; Liang, M. C.; Jiang, X.; Newman, C. E.; Tung, K. K.; Yung, Y. L.

2015-12-01

With the advance of modern computers, studies of planetary atmospheres have heavily relied on general circulation models (GCMs). Because these GCMs are usually very complicated, the simulations are sometimes difficult to understand. Here we develop a semi-analytic zonally averaged, cyclostrophic residual Eulerian model to illustrate how some of the large-scale structures of the middle atmospheric circulation can be explained qualitatively in terms of simple thermal (e.g. solar heating) and mechanical (the Eliassen-Palm flux divergence) forcings. This model is a generalization of that for fast rotating planets such as the Earth, where geostrophy dominates (Andrews and McIntyre 1987). The solution to this semi-analytic model consists of a set of modified Hough functions of the generalized Laplace's tidal equation with the cyclostrohpic terms. As examples, we apply this model to Titan and Venus. We show that the seasonal variations of the temperature and the circulation of these slowly-rotating planets can be well reproduced by adjusting only three parameters in the model: the Brunt-Väisälä bouyancy frequency, the Newtonian radiative cooling rate, and the Rayleigh friction damping rate. We will also discuss the application of this model to study the meridional transport of photochemically produced tracers that can be observed by space instruments.

A cyclostrophic transformed Eulerian zonal mean model for the middle atmosphere of slowly rotating planets

NASA Astrophysics Data System (ADS)

Li, King-Fai; Yao, Kaixuan; Taketa, Cameron; Zhang, Xi; Liang, Mao-Chang; Jiang, Xun; Newman, Claire; Tung, Ka-Kit; Yung, Yuk L.

2016-04-01

With the advance of modern computers, studies of planetary atmospheres have heavily relied on general circulation models (GCMs). Because these GCMs are usually very complicated, the simulations are sometimes difficult to understand. Here we develop a semi-analytic zonally averaged, cyclostrophic residual Eulerian model to illustrate how some of the large-scale structures of the middle atmospheric circulation can be explained qualitatively in terms of simple thermal (e.g. solar heating) and mechanical (the Eliassen-Palm flux divergence) forcings. This model is a generalization of that for fast rotating planets such as the Earth, where geostrophy dominates (Andrews and McIntyre 1987). The solution to this semi-analytic model consists of a set of modified Hough functions of the generalized Laplace's tidal equation with the cyclostrohpic terms. As an example, we apply this model to Titan. We show that the seasonal variations of the temperature and the circulation of these slowly-rotating planets can be well reproduced by adjusting only three parameters in the model: the Brunt-Väisälä bouyancy frequency, the Newtonian radiative cooling rate, and the Rayleigh friction damping rate. We will also discuss an application of this model to study the meridional transport of photochemically produced tracers that can be observed by space instruments.

Reform-based science teaching: A mixed-methods approach to explaining variation in secondary science teacher practice

NASA Astrophysics Data System (ADS)

Jetty, Lauren E.

The purpose of this two-phase, sequential explanatory mixed-methods study was to understand and explain the variation seen in secondary science teachers' enactment of reform-based instructional practices. Utilizing teacher socialization theory, this mixed-methods analysis was conducted to determine the relative influence of secondary science teachers' characteristics, backgrounds and experiences across their teacher development to explain the range of teaching practices exhibited by graduates from three reform-oriented teacher preparation programs. Data for this study were obtained from the Investigating the Meaningfulness of Preservice Programs Across the Continuum of Teaching (IMPPACT) Project, a multi-university, longitudinal study funded by NSF. In the first quantitative phase of the study, data for the sample (N=120) were collected from three surveys from the IMPPACT Project database. Hierarchical multiple regression analysis was used to examine the separate as well as the combined influence of factors such as teachers' personal and professional background characteristics, beliefs about reform-based science teaching, feelings of preparedness to teach science, school context, school culture and climate of professional learning, and influences of the policy environment on the teachers' use of reform-based instructional practices. Findings indicate three blocks of variables, professional background, beliefs/efficacy, and local school context added significant contribution to explaining nearly 38% of the variation in secondary science teachers' use of reform-based instructional practices. The five variables that significantly contributed to explaining variation in teachers' use of reform-based instructional practices in the full model were, university of teacher preparation, sense of preparation for teaching science, the quality of professional development, science content focused professional, and the perceived level of professional autonomy. Using the results from phase one, the second qualitative phase selected six case study teachers based on their levels of reform-based teaching practices to highlight teachers across the range of practices from low, average, to high levels of implementation. Using multiple interview sources, phase two helped to further explain the variation in levels of reform-based practices. Themes related to teachers' backgrounds, local contexts, and state policy environments were developed as they related to teachers' socialization experiences across these contexts. The results of the qualitative analysis identified the following factors differentiating teachers who enacted reform-based instructional practices from those who did not: 1) extensive science research experiences prior to their preservice teacher preparation; 2) the structure and quality of their field placements; 3) developing and valuing a research-based understanding of teaching and learning as a result of their preservice teacher preparation experiences; 4) the professional culture of their school context where there was support for a high degree of professional autonomy and receiving support from "educational companions" with a specific focus on teacher pedagogy to support student learning; and 5) a greater sense of agency to navigate their districts' interpretation and implementation of state polices. Implications for key stakeholders as well as directions for future research are discussed.

Medical Educators' Social Acts of Explaining Passing Underperformance in Students: A Qualitative Study

ERIC Educational Resources Information Center

Monrouxe, Lynn V.; Rees, Charlotte E.; Lewis, Natalie J.; Cleland, Jennifer A.

2011-01-01

Passing underperformance in students is ubiquitous across health and social care educators and is intimately related to the subsequent welfare of patients: underperforming students may become underperforming practitioners. This paper aims to examine how medical educators construct passing underperformance through an analysis of their social act of…

The Production of Therapy: The Social Process of Construction of the Mother of a Sexually Abused Child

ERIC Educational Resources Information Center

Joyce, Patricia A.

2007-01-01

This study qualitatively examined the perspectives of clinical social workers on non-offending mothers of sexually abused children. The study examined whether clinicians still used collusion to explain mothers' behavior, despite research refuting collusion. Findings revealed that, although workers did not use collusion, they still constructed…

Strategies for Employee Learning in Professional Service Firms: A Study of Community Pharmacies in Australia

ERIC Educational Resources Information Center

Kotey, Bernice; Saini, Bandana; While, Lesley

2011-01-01

The study investigated employee learning strategies in community pharmacies in Australia and the factors that explain differences among pharmacies in the strategies employed. A qualitative methodology was applied, involving semi-structured interviews with owners, managers, or senior employees of 12 pharmacies. The findings revealed learning…

Intimate Inquiry: A Love-Based Approach to Qualitative Research

ERIC Educational Resources Information Center

Laura, Crystal T.

2016-01-01

Academics have a hard time talking about the role of "love" in social research, and the lack of a working definition for its meaning only partly explains our difficulty. The more substantial barrier is our tendency to think about "research" not as a careful exploration of specific social, intellectual, or methodological…

Teacher Training through Social Networking Platforms: A Case Study on Facebook

ERIC Educational Resources Information Center

Çevik, Yasemin Demiraslan; Çelik, Serkan; Haslaman, Tülin

2014-01-01

Numerous studies have attempted to explain the role of social networking platforms within educational environments, though none of them has reported on their potential for enhancing professional development in education. The purpose of this qualitative research was to explore the reflections of prospective teachers who were assigned to design and…

When Does Race Matter? Race, Sex, and Dating at an Elite University

ERIC Educational Resources Information Center

McClintock, Elizabeth Aura

2010-01-01

This paper unites quantitative and qualitative data from the College Social Life Survey (n = 732) to describe and explain patterns of racial homophily in undergraduate sexual/romantic relationships at an elite university, a closed social setting. It expands the literature on interracial romantic unions by comparing homophily in hookups…

A Phenomenological Examination of Perceived Skills and Concepts Necessary for Teaching Scientific Thinking

ERIC Educational Resources Information Center

Kapetanis, Ana Cristina

2011-01-01

The use of high stakes testing to improve educational outcomes falls short in many settings. Proposals for improvement include providing more opportunities for students to extend their thinking, gaining experience in the social nature of science, and learning how to interpret, explain, and justify results. This phenomenological qualitative project…

The Myth of Peer Pressure.

ERIC Educational Resources Information Center

Ungar, Michael T.

2000-01-01

The construct of peer pressure was examined as part of a qualitative study of the determinants of mental health for 41 high-risk adolescents. While the concept of peer pressure enables adults to explain youths' troubling behaviors, content analysis of the participants' accounts of their lives reveals peer pressure to be a myth. (Author/MKA)

Appreciative Accreditation: A Mixed Methods Explanatory Study of Appreciative Inquiry-Based Institutional Effectiveness Results in Higher Education

ERIC Educational Resources Information Center

Thibodeau, John

2011-01-01

This study examined the effects of using Appreciative Inquiry in accreditation and related institutional effectiveness activities within higher education. Using an explanatory participant-selection mixed methods approach, qualitative data from a series of interviews were used to explain the experiences of individuals identified from quantitative…

Theoretical Factors Affecting Parental Roles in Children's Mathematical Learning in American and Chinese-Born Mothers

ERIC Educational Resources Information Center

Hunt, Jessica H.; Hu, Bi Ying

2011-01-01

This introductory qualitative study sought to explain American and Chinese-born mothers' personal beliefs and experiences with mathematics, views of U.S. mathematics curriculum, and how these factors influenced motivation regarding roles played in their children's mathematical learning through expectancy-value and attribution theories. The…

Female Academic Leadership in the Post-Soviet Context

ERIC Educational Resources Information Center

Kuzhabekova, Aliya; Almukhambetova, Ainur

2017-01-01

Using a qualitative interview approach, this study analyzes the experiences of women in academic leadership positions in post-Soviet Kazakhstan. An exploration of the extent of the relevance of Western research on female academic leadership is used to explain the experiences of female leaders in Kazakhstan. The results of the study are consistent…

Learning Qualitative and Quantitative Reasoning in a Microworld for Elastic Impacts.

ERIC Educational Resources Information Center

Ploetzner, Rolf; And Others

1990-01-01

Discusses the artificial-intelligence-based microworld DiBi and MULEDS, a multilevel diagnosis system. Developed to adapt tutoring style to the individual learner. Explains that DiBi sets up a learning environment, and simulates elastic impacts as a subtopic of classical mechanics, and supporting reasoning on different levels of mental domain…

Women's Access to Higher Education in Tanzania: A Qualitative Study

ERIC Educational Resources Information Center

Johnson, Megan Patricia

2011-01-01

The purpose of this study was to reveal the ways in which first-generation women in Tanzania explained their success in pursuing a university education despite cultural and social obstacles. Such obstacles include social policies, socio-cultural factors, and academic factors. A review of the literature revealed that issues such as patriarchy,…

Sensitivity of jet substructure to jet-induced medium response

NASA Astrophysics Data System (ADS)

Milhano, Guilherme; Wiedemann, Urs Achim; Zapp, Korinna Christine

2018-04-01

Jet quenching in heavy ion collisions is expected to be accompanied by recoil effects, but unambiguous signals for the induced medium response have been difficult to identify so far. Here, we argue that modern jet substructure measurements can improve this situation qualitatively since they are sensitive to the momentum distribution inside the jet. We show that the groomed subjet shared momentum fraction zg, and the girth of leading and subleading subjets signal recoil effects with dependencies that are absent in a recoilless baseline. We find that recoil effects can explain most of the medium modifications to the zg distribution observed in data. Furthermore, for jets passing the Soft Drop Condition, recoil effects induce in the differential distribution of subjet separation ΔR12 a characteristic increase with ΔR12, and they introduce a characteristic enhancement of the girth of the subleading subjet with decreasing zg. We explain why these qualitatively novel features, that we establish in JEWEL+PYTHIA simulations, reflect generic physical properties of recoil effects that should therefore be searched for as telltale signatures of jet-induced medium response.

Frustration and Dzyaloshinsky-Moriya anisotropy in the kagome francisites Cu3Bi (SeO3)2 O2X (X = Br , Cl )

NASA Astrophysics Data System (ADS)

Rousochatzakis, Ioannis; Richter, Johannes; Zinke, Ronald; Tsirlin, Alexander A.

2015-01-01

We investigate the antiferromagnetic canting instability of the spin-1/2 kagome ferromagnet, as realized in the layered cuprates Cu3Bi (SeO3)2 O2X (X = Br , Cl ). While the local canting can be explained in terms of competing exchange interactions, the direction of the ferrimagnetic order parameter fluctuates strongly even at short distances on account of frustration which gives rise to an infinite ground state degeneracy at the classical level. In analogy with the kagome antiferromagnet, the accidental degeneracy is fully lifted only by nonlinear 1 /S corrections, rendering the selected uniform canted phase very fragile even for spins-1/2, as shown explicitly by coupled-cluster calculations. To account for the observed ordering, we show that the minimal description of these systems must include the microscopic Dzyaloshinsky-Moriya interactions, which we obtain from density-functional band-structure calculations. The model explains all qualitative properties of the kagome francisites, including the detailed nature of the ground state and the anisotropic response under a magnetic field. The predicted magnon excitation spectrum and quantitative features of the magnetization process call for further experimental investigations of these compounds.

Laboratory simulations of cumulus cloud flows explain the entrainment anomaly

NASA Astrophysics Data System (ADS)

Narasimha, Roddam; Diwan, Sourabh S.; Subrahmanyam, Duvvuri; Sreenivas, K. R.; Bhat, G. S.

2010-11-01

In the present laboratory experiments, cumulus cloud flows are simulated by starting plumes and jets subjected to off-source heat addition in amounts that are dynamically similar to latent heat release due to condensation in real clouds. The setup permits incorporation of features like atmospheric inversion layers and the active control of off-source heat addition. Herein we report, for the first time, simulation of five different cumulus cloud types (and many shapes), including three genera and three species (WMO Atlas 1987), which show striking resemblance to real clouds. It is known that the rate of entrainment in cumulus cloud flows is much less than that in classical plumes - the main reason for the failure of early entrainment models. Some of the previous studies on steady-state jets and plumes (done in a similar setup) have attributed this anomaly to the disruption of the large-scale turbulent structures upon the addition of off-source heat. We present estimates of entrainment coefficients from these measurements which show a qualitatively consistent variation with height. We propose that this explains the observed entrainment anomaly in cumulus clouds; further experiments are planned to address this question in the context of starting jets and plumes.

History dependent crystallization of Zr{sub 41}Ti{sub 14}Cu{sub 12}Ni{sub 10}Be{sub 23} melts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroers, Jan; Johnson, William L.

The crystallization of Zr{sub 41}Ti{sub 14}Cu{sub 12}Ni{sub 10}Be{sub 23} (Vit 1) melts during constant heating is investigated. (Vit 1) melts are cooled with different rates into the amorphous state and the crystallization temperature upon subsequent heating is studied. In addition, Vit 1 melts are cooled using a constant rate to different temperatures and subsequently heated from this temperature with a constant rate. We investigate the influence of the temperature to which the melt was cooled on the crystallization temperature measured upon heating. In both cases the onset temperature of crystallization shows strong history dependence. This can be explained by anmore » accumulating process during cooling and heating. An attempt is made to consider this process in a simple model by steady state nucleation and subsequent growth of the nuclei which results in different crystallization kinetics during cooling or heating. Calculations show qualitative agreement with the experimental results. However, calculated and experimental results differ quantitatively. This difference can be explained by a decomposition process leading to a nonsteady nucleation rate which continuously increases with decreasing temperature. (c) 2000 American Institute of Physics.« less

Experienced Practitioners' Beliefs Utilized to Create a Successful Massage Therapist Conceptual Model: a Qualitative Investigation.

PubMed

Kennedy, Anne B; Munk, Niki

2017-06-01

The massage therapy profession in the United States has grown exponentially, with 35% of the profession's practitioners in practice for three years or less. Investigating personal and social factors with regard to the massage therapy profession could help to identify constructs needed to be successful in the field. This data-gathering exercise explores massage therapists' perceptions on what makes a successful massage therapist that will provide guidance for future research. Success is defined as supporting oneself and practice solely through massage therapy and related, revenue-generating field activity. Ten successful massage therapy practitioners from around the United States who have a minimum of five years of experience. Semistructured qualitative interviews were used in an analytic induction framework; index cards with preidentified concepts printed on them were utilized to enhance conversation. An iterative process of interview coding and analysis was used to determine themes and subthemes. Based on the participants input, the categories in which therapists needed to be successful were organized into four main themes: effectively establish therapeutic relationships, develop massage therapy business acumen, seek valuable learning environments and opportunities, and cultivate strong social ties and networks. The four themes operate within specific contexts (e.g., regulation and licensing requirements in the therapists' state), which may also influence the success of the massage therapist. The model needs to be tested to explore which constructs explain variability in success and attrition rate. Limitations and future research implications are discussed.

Situational trust and co-operative partnerships between physicians and their patients: a theoretical explanation transferable from business practice.

PubMed

Dibben, M R; Morris, S E; Lean, M E

2000-01-01

A model to explain interpersonal trust development, and its consequences for co-operative behaviour in doctor/patient partnerships derived from the context of business relationships is applied to patient/physician relationships. Threshold barriers exist against all human behaviours or actions and trust is the process by which barriers to co-operation and compliance are overcome. Dispositional trust (a psychological trait to be trusting) is dominant in the early stages of a relationship and contributes to the weight of subsequent trust development. Co-operative behaviour or compliance ultimately requires a secure situational trust emerging from consultations, which is carried forward as learnt trust and modified in each subsequent consultation. The model comprises three types of situational trust (calculus-based, knowledge-based, and identification trust) and five co-operation criteria from which to determine an individual's tendency for co- operative behaviour. These model components can be identified and mapped from a range of qualitative data, with the aim of enhancing co-operative behaviour and efficiently achieving optimal patient compliance.

On the origin of the water vapor continuum absorption within rotational and fundamental vibrational bands

NASA Astrophysics Data System (ADS)

Serov, E. A.; Odintsova, T. A.; Tretyakov, M. Yu.; Semenov, V. E.

2017-05-01

Analysis of the continuum absorption in water vapor at room temperature within the purely rotational and fundamental ro-vibrational bands shows that a significant part (up to a half) of the observed absorption cannot be explained within the framework of the existing concepts of the continuum. Neither of the two most prominent mechanisms of continuum originating, namely, the far wings of monomer lines and the dimers, cannot reproduce the currently available experimental data adequately. We propose a new approach to developing a physically based model of the continuum. It is demonstrated that water dimers and wings of monomer lines may contribute equally to the continuum within the bands, and their contribution should be taken into account in the continuum model. We propose a physical mechanism giving missing justification for the super-Lorentzian behavior of the intermediate line wing. The qualitative validation of the proposed approach is given on the basis of a simple empirical model. The obtained results are directly indicative of the necessity to reconsider the existing line wing theory and can guide this consideration.

The Active Role of the Ocean in the Temporal Evolution of Climate Sensitivity

DOE PAGES

Garuba, Oluwayemi A.; Lu, Jian; Liu, Fukai; ...

2017-11-30

Here, the temporal evolution of the effective climate sensitivity is shown to be influenced by the changing pattern of sea surface temperature (SST) and ocean heat uptake (OHU), which in turn have been attributed to ocean circulation changes. A set of novel experiments are performed to isolate the active role of the ocean by comparing a fully coupled CO 2 quadrupling community Earth System Model (CESM) simulation against a partially coupled one, where the effect of the ocean circulation change and its impact on surface fluxes are disabled. The active OHU is responsible for the reduced effective climate sensitivity andmore » weaker surface warming response in the fully coupled simulation. The passive OHU excites qualitatively similar feedbacks to CO 2 quadrupling in a slab ocean model configuration due to the similar SST spatial pattern response in both experiments. Additionally, the nonunitary forcing efficacy of the active OHU (1.7) explains the very different net feedback parameters in the fully and partially coupled responses.« less

Strategies and challenges for communicating the diagnosis of cancer in cross-cultural clinical settings-Perspectives from South African healthcare professionals.

PubMed

Brown, Ottilia; Goliath, Veonna; van Rooyen, Dalena R M; Aldous, Colleen; Marais, Leonard Charles

2017-01-01

Communicating the diagnosis of cancer in cross-cultural clinical settings is a complex task. This qualitative research article describes the content and process of informing Zulu patients in South Africa of the diagnosis of cancer, using osteosarcoma as the index diagnosis. We used a descriptive research design with census sampling and focus group interviews. We used an iterative thematic data analysis process and Guba's model of trustworthiness to ensure scientific rigor. Our results reinforced the use of well-accepted strategies for communicating the diagnosis of cancer. In addition, new strategies emerged which may be useful in other cross-cultural settings. These strategies included using the stages of cancer to explain the disease and its progression and instilling hope using a multidisciplinary team care model. We identified several patients, professionals, and organizational factors that complicate cross-cultural communication. We conclude by recommending the development of protocols for communication in these cross-cultural clinical settings.

Collective coordinates theory for discrete soliton ratchets in the sine-Gordon model

NASA Astrophysics Data System (ADS)

Sánchez-Rey, Bernardo; Quintero, Niurka R.; Cuevas-Maraver, Jesús; Alejo, Miguel A.

2014-10-01

A collective coordinate theory is developed for soliton ratchets in the damped discrete sine-Gordon model driven by a biharmonic force. An ansatz with two collective coordinates, namely the center and the width of the soliton, is assumed as an approximated solution of the discrete nonlinear equation. The dynamical equations of these two collective coordinates, obtained by means of the generalized travelling wave method, explain the mechanism underlying the soliton ratchet and capture qualitatively all the main features of this phenomenon. The numerical simulation of these equations accounts for the existence of a nonzero depinning threshold, the nonsinusoidal behavior of the average velocity as a function of the relative phase between the harmonics of the driver, the nonmonotonic dependence of the average velocity on the damping, and the existence of nontransporting regimes beyond the depinning threshold. In particular, it provides a good description of the intriguing and complex pattern of subspaces corresponding to different dynamical regimes in parameter space.

Collective coordinates theory for discrete soliton ratchets in the sine-Gordon model.

PubMed

Sánchez-Rey, Bernardo; Quintero, Niurka R; Cuevas-Maraver, Jesús; Alejo, Miguel A

2014-10-01

A collective coordinate theory is developed for soliton ratchets in the damped discrete sine-Gordon model driven by a biharmonic force. An ansatz with two collective coordinates, namely the center and the width of the soliton, is assumed as an approximated solution of the discrete nonlinear equation. The dynamical equations of these two collective coordinates, obtained by means of the generalized travelling wave method, explain the mechanism underlying the soliton ratchet and capture qualitatively all the main features of this phenomenon. The numerical simulation of these equations accounts for the existence of a nonzero depinning threshold, the nonsinusoidal behavior of the average velocity as a function of the relative phase between the harmonics of the driver, the nonmonotonic dependence of the average velocity on the damping, and the existence of nontransporting regimes beyond the depinning threshold. In particular, it provides a good description of the intriguing and complex pattern of subspaces corresponding to different dynamical regimes in parameter space.

The Active Role of the Ocean in the Temporal Evolution of Climate Sensitivity

NASA Astrophysics Data System (ADS)

Garuba, Oluwayemi A.; Lu, Jian; Liu, Fukai; Singh, Hansi A.

2018-01-01

The temporal evolution of the effective climate sensitivity is shown to be influenced by the changing pattern of sea surface temperature (SST) and ocean heat uptake (OHU), which in turn have been attributed to ocean circulation changes. A set of novel experiments are performed to isolate the active role of the ocean by comparing a fully coupled CO2 quadrupling community Earth System Model (CESM) simulation against a partially coupled one, where the effect of the ocean circulation change and its impact on surface fluxes are disabled. The active OHU is responsible for the reduced effective climate sensitivity and weaker surface warming response in the fully coupled simulation. The passive OHU excites qualitatively similar feedbacks to CO2 quadrupling in a slab ocean model configuration due to the similar SST spatial pattern response in both experiments. Additionally, the nonunitary forcing efficacy of the active OHU (1.7) explains the very different net feedback parameters in the fully and partially coupled responses.

Effects of pacing magnitudes and forms on bistability width in a modeled ventricular tissue

NASA Astrophysics Data System (ADS)

Huang, Xiaodong; Liu, Xuemei; Zheng, Lixian; Mi, Yuanyuan; Qian, Yu

2013-07-01

Bistability in periodically paced cardiac tissue is relevant to cardiac arrhythmias and its control. In the present paper, one-dimensional tissue of the phase I Luo-Rudy model is numerically investigated. The effects of various parameters of pacing signals on bistability width are studied. The following conclusions are obtained: (i) Pacing can be classified into two types: pulsatile and sinusoidal types. Pulsatile pacing reduces bistability width as its magnitude is increased. Sinusoidal pacing increases the width as its amplitude is increased. (ii) In a pacing period the hyperpolarizing part plays a more important role than the depolarizing part. Variations of the hyperpolarizing ratio in a period evidently change the width of bistability and its variation tendency. (iii) A dynamical mechanism is proposed to qualitatively explain the phenomena, which reveals the reason for the different effects of pulsatile and sinusoidal pacing on bistability. The methods for changing bistability width by external pacing may help control arrhythmias in cardiology.

Evolutionary dynamics of selfish DNA explains the abundance distribution of genomic subsequences

PubMed Central

Sheinman, Michael; Ramisch, Anna; Massip, Florian; Arndt, Peter F.

2016-01-01

Since the sequencing of large genomes, many statistical features of their sequences have been found. One intriguing feature is that certain subsequences are much more abundant than others. In fact, abundances of subsequences of a given length are distributed with a scale-free power-law tail, resembling properties of human texts, such as Zipf’s law. Despite recent efforts, the understanding of this phenomenon is still lacking. Here we find that selfish DNA elements, such as those belonging to the Alu family of repeats, dominate the power-law tail. Interestingly, for the Alu elements the power-law exponent increases with the length of the considered subsequences. Motivated by these observations, we develop a model of selfish DNA expansion. The predictions of this model qualitatively and quantitatively agree with the empirical observations. This allows us to estimate parameters for the process of selfish DNA spreading in a genome during its evolution. The obtained results shed light on how evolution of selfish DNA elements shapes non-trivial statistical properties of genomes. PMID:27488939

The opto-thermal effect on encapsulated cholesteric liquid crystals

NASA Astrophysics Data System (ADS)

Liu, Yu-Sung; Lin, Hui-Chi; Yang, Kin-Min

2017-12-01

In this study, we implemented a micro-encapsulated CLC electronic paper that is optically addressed and electrically erasable. The mechanism that forms spot diameters on the CLC films is discussed and verified through various experimental parameters, including the thickness of CLCs and Poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrenesulfonate) (PEDOT:PSS), pump intensity, and pumping time. The opto-thermal effect, brought on by the PEDOT:PSS absorbing layer, causes the spot diameters on the cholesteric liquid crystal thin films to vary. According to our results, the spot diameter is larger for a sample with a thinner cholesteric liquid crystal layer with the same excitation conditions and same thickness of the PEDOT layer. The spot diameter is also larger for a sample with a thicker PEDOT under the same excitation conditions and same thickness of the cholesteric liquid crystal layer. We proposed a simple heat-conducting model to explain the experimental results, which qualitatively agree with this theoretical model.

Negative magnetoresistance of ultra-narrow superconducting nanowires in the resistive state

NASA Astrophysics Data System (ADS)

Arutyunov, K. Yu.

2008-02-01

We present a phenomenological model that qualitatively explains negative magnetoresistance in quasi-one-dimensional superconducting channels in the resistive state. The model is based on the assumption that fluctuations of the order parameter (phase slips) are responsible for the finite effective resistance of a narrow superconducting wire sufficiently close to the critical temperature. Each fluctuation is accompanied by an instantaneous formation of a quasi-normal region, of the order of the non-equilibrium quasiparticle relaxation length, ‘pinned’ to the core of the phase slip. The effective time-averaged voltage measured in experiments is a sum of two terms. The first is the conventional contribution associated with the rate of the fluctuations via the Josephson relation. The second term is the Ohmic contribution of this quasi-normal region. Depending on the material properties of the wire, there might be a range of magnetic fields where the first term is not significantly affected, while the second term is effectively suppressed, contributing to the experimentally observed negative magnetoresistance.

Phase diagram and quantum order by disorder in the Kitaev K1-K2 honeycomb magnet

NASA Astrophysics Data System (ADS)

Rousochatzakis, Ioannis; Reuther, Johannes; Thomale, Ronny; Rachel, Stephan; Perkins, Natalia

We show that the topological Kitaev spin liquid on the honeycomb lattice is extremely fragile against the second neighbor Kitaev coupling K2, which has been recently identified as the dominant perturbation away from the nearest neighbor model in iridate Na2IrO3, and may also play a role in α-RuCl3. This coupling explains naturally the zig-zag ordering and the special entanglement between real and spin space observed recently in Na2IrO3. The minimal K1-K2 model that we present here holds in addition the unique property that the classical and quantum phase diagrams and their respective order-by-disorder mechanisms are qualitatively different due to their fundamentally different symmetry structure. Nsf DMR-1511768; Freie Univ. Berlin Excellence Initiative of German Research Foundation; European Research Council, ERC-StG-336012; DFG-SFB 1170; DFG-SFB 1143, DFG-SPP 1666, and Helmholtz association VI-521.

The Active Role of the Ocean in the Temporal Evolution of Climate Sensitivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garuba, Oluwayemi A.; Lu, Jian; Liu, Fukai

Here, the temporal evolution of the effective climate sensitivity is shown to be influenced by the changing pattern of sea surface temperature (SST) and ocean heat uptake (OHU), which in turn have been attributed to ocean circulation changes. A set of novel experiments are performed to isolate the active role of the ocean by comparing a fully coupled CO 2 quadrupling community Earth System Model (CESM) simulation against a partially coupled one, where the effect of the ocean circulation change and its impact on surface fluxes are disabled. The active OHU is responsible for the reduced effective climate sensitivity andmore » weaker surface warming response in the fully coupled simulation. The passive OHU excites qualitatively similar feedbacks to CO 2 quadrupling in a slab ocean model configuration due to the similar SST spatial pattern response in both experiments. Additionally, the nonunitary forcing efficacy of the active OHU (1.7) explains the very different net feedback parameters in the fully and partially coupled responses.« less

Properties of four real world collaboration--competition networks

NASA Astrophysics Data System (ADS)

Fu, Chun-Hua; Xu, Xiu-Lian; He, Da-Ren

2009-03-01

Our research group has empirically investigated 9 real world collaboration networks and 25 real world cooperation-competition networks. Among the 34 real world systems, all the 9 real world collaboration networks and 6 real world cooperation-competition networks show the unimodal act-size distribution and the shifted power law distribution of degree and act-degree. We have proposed a collaboration network evolution model for an explanation of the rules [1]. The other 14 real world cooperation-competition networks show that the act-size distributions are not unimodal; instead, they take qualitatively the same shifted power law forms as the degree and act-degree distributions. The properties of four systems (the main land movie film network, Beijing restaurant network, 2004 Olympic network, and Tao-Bao notebook computer sale network) are reported in detail as examples. Via a numerical simulation, we show that the new rule can still be explained by the above-mentioned model. [1] H. Chang, B. B. Su, et al. Phsica A, 2007, 383: 687-702.

Qualitative dynamics semantics for SBGN process description.

PubMed

Rougny, Adrien; Froidevaux, Christine; Calzone, Laurence; Paulevé, Loïc

2016-06-16

Qualitative dynamics semantics provide a coarse-grain modeling of networks dynamics by abstracting away kinetic parameters. They allow to capture general features of systems dynamics, such as attractors or reachability properties, for which scalable analyses exist. The Systems Biology Graphical Notation Process Description language (SBGN-PD) has become a standard to represent reaction networks. However, no qualitative dynamics semantics taking into account all the main features available in SBGN-PD had been proposed so far. We propose two qualitative dynamics semantics for SBGN-PD reaction networks, namely the general semantics and the stories semantics, that we formalize using asynchronous automata networks. While the general semantics extends standard Boolean semantics of reaction networks by taking into account all the main features of SBGN-PD, the stories semantics allows to model several molecules of a network by a unique variable. The obtained qualitative models can be checked against dynamical properties and therefore validated with respect to biological knowledge. We apply our framework to reason on the qualitative dynamics of a large network (more than 200 nodes) modeling the regulation of the cell cycle by RB/E2F. The proposed semantics provide a direct formalization of SBGN-PD networks in dynamical qualitative models that can be further analyzed using standard tools for discrete models. The dynamics in stories semantics have a lower dimension than the general one and prune multiple behaviors (which can be considered as spurious) by enforcing the mutual exclusiveness between the activity of different nodes of a same story. Overall, the qualitative semantics for SBGN-PD allow to capture efficiently important dynamical features of reaction network models and can be exploited to further refine them.

Preliminary Development of the Food Allergy Coping and Emotions Questionnaires for Children, Adolescents, and Young People: Qualitative Analysis of Data on IgE-Mediated Food Allergy from Five Countries.

PubMed

DunnGalvin, Audrey; Polloni, Laura; Le Bovidge, Jennifer; Muraro, Antonella; Greenhawt, Matthew; Taylor, Steve; Baumert, Joseph; Burks, Wesley; Trace, Anna; DunnGalvin, Gillian; Forristal, Lisa; McGrath, Laura; White, Jennifer; Vasquez, Marta; Allen, Katrina; Sheikh, Aziz; Hourihane, Jonathan; Tang, Mimi L K

We have previously developed a food allergy-specific developmental model, that explained emotions and coping styles, among children aged 6 to 15years in Ireland. The objective of this study was to investigate the usefulness of the developmental model in a large multicountry data set, including any mediators of coping style, and to use the findings to generate an item pool that will form the basis for 3 age-appropriate self-report questionnaires to measure coping and emotions. We conducted deductive thematic analysis on secondary data from interviews with 274 participants aged 6 to 23 years, and 119 parents from Australia, Ireland, Italy, the UK, and the USA. Analysis was undertaken across the entire data set. The Food Allergy Coping and Emotions (FACE) model has 5 major themes: (1) experiences and emotions, (2) search for normality, (3) management and coping, (4) "external mediators," and (5) "internal mediators" (between emotions and coping). These themes were present across countries, but differed according to age. Early-life experiences provide the foundation for later cognitions and behaviors. The expanded FACE developmental model is useful in explaining emotions and coping styles across different age groups and countries. These data will also be used to generate an age-specific bank of items for the development of 3 (age-specific self-report, and parent proxy) questionnaires to assess emotions and coping in food allergy. Findings provide insight into how particular styles of coping develop and vary from patient to patient and may also guide clinician-patient communication and the development of individualized management strategies. Copyright © 2018. Published by Elsevier Inc.

Qualitative simulation for process modeling and control

NASA Technical Reports Server (NTRS)

Dalle Molle, D. T.; Edgar, T. F.

1989-01-01

A qualitative model is developed for a first-order system with a proportional-integral controller without precise knowledge of the process or controller parameters. Simulation of the qualitative model yields all of the solutions to the system equations. In developing the qualitative model, a necessary condition for the occurrence of oscillatory behavior is identified. Initializations that cannot exhibit oscillatory behavior produce a finite set of behaviors. When the phase-space behavior of the oscillatory behavior is properly constrained, these initializations produce an infinite but comprehensible set of asymptotically stable behaviors. While the predictions include all possible behaviors of the real system, a class of spurious behaviors has been identified. When limited numerical information is included in the model, the number of predictions is significantly reduced.

Are there two processes in reasoning? The dimensionality of inductive and deductive inferences.

PubMed

Stephens, Rachel G; Dunn, John C; Hayes, Brett K

2018-03-01

Single-process accounts of reasoning propose that the same cognitive mechanisms underlie inductive and deductive inferences. In contrast, dual-process accounts propose that these inferences depend upon 2 qualitatively different mechanisms. To distinguish between these accounts, we derived a set of single-process and dual-process models based on an overarching signal detection framework. We then used signed difference analysis to test each model against data from an argument evaluation task, in which induction and deduction judgments are elicited for sets of valid and invalid arguments. Three data sets were analyzed: data from Singmann and Klauer (2011), a database of argument evaluation studies, and the results of an experiment designed to test model predictions. Of the large set of testable models, we found that almost all could be rejected, including all 2-dimensional models. The only testable model able to account for all 3 data sets was a model with 1 dimension of argument strength and independent decision criteria for induction and deduction judgments. We conclude that despite the popularity of dual-process accounts, current results from the argument evaluation task are best explained by a single-process account that incorporates separate decision thresholds for inductive and deductive inferences. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Turbulence evolution and transport behavior during current ramp-up in ITER-like plasmas on DIII-D

DOE PAGES

McKee, George R.; Austin, Max E.; Boedo, Jose A.; ...

2017-07-12

Low-wavenumber density fluctuations exhibit unique characteristics during the current ramp-up phase of ITER-like discharges that can partially explain the challenges of correctly modeling transport behavior and predicting global plasma parameters during this period. A strong interaction takes place between the evolving transport, safety factor (q) and kinetic profiles as well as the appearance and evolution of low-order rational surfaces. Density fluctuations from 0.75 < ρ < 0.9 are transiently reduced to exceptionally low levels during early times and from 0.8 < ρ < 0.9 at late times in the ramp-up in a manner that is different from behavior observed duringmore » steady-state plasma conditions with similar values of q 95. Turbulence is suppressed as low-order-rational q-surfaces enter the plasma; the local electron temperature likewise exhibits transient increases during these periods of reduced fluctuations indicating changes in transport that impact temperature and consequently the evolution of current density and plasma inductance. These observations can explain discrepancies between CORSICA modelling and the higher electron temperature found previously over the outer half radius. Comparison of turbulence properties with time-varying linear growth rates with GYRO and GENE demonstrate qualitative consistency with measured fluctuation levels, but calculations don’t exhibit reduced growth rates near low-order rational surfaces, which is inconsistent with experimental observations. Here, this indicates a mechanism that can contribute to reconciling observed turbulence behavior with transport models, allowing for the development of more accurate predictive tools.« less

TRACING INFALL AND ROTATION ALONG THE OUTFLOW CAVITY WALLS OF THE L483 PROTOSTELLAR ENVELOPE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leung, Gigi Y.C.; Lim, Jeremy; Takakuwa, Shigehisa

2016-12-10

Single-dish observations in CS(7–6) reveal emission extending out to thousands of au along the outflow axis of low-mass protostars and having a velocity gradient in the opposite direction to that of their outflows. This emission has been attributed to dense and warm gas flowing outward along the walls of bipolar outflow cavities. Here, we present combined single-dish and interferometric CS(7–6) maps for the low-mass protostar L483, revealing a newly discovered compact central component (radius ≲800 au) and previously unknown features in its extended component (visible out to ∼4000 au). The velocity gradient and skewed (toward the redshifted side) brightness distributionmore » of the extended component are detectable out to a radius of ∼2000 au, but not beyond. The compact central component exhibits a velocity gradient in the same direction as, but which is steeper than that of, the extended component. Furthermore, both components exhibit a velocity gradient with an approximately constant magnitude across the outflow axis, apparent in the extended component not just through but also away from the center out to 2000 au. We point out contradictions between our results and model predictions for outflowing gas and propose a new model in which all of the aforementioned emission can be qualitatively explained by gas inflowing along the outflow cavity walls of a rigidly rotating envelope. Our model also can explain the extended CS(7–6) emission observed around other low-mass protostars.« less

Turbulence evolution and transport behavior during current ramp-up in ITER-like plasmas on DIII-D

NASA Astrophysics Data System (ADS)

McKee, G. R.; Austin, M.; Boedo, J.; Bravenec, R.; Holland, C.; Jackson, G.; Luce, T. C.; Rhodes, T. L.; Rudakov, D.; Wang, G.; Yan, Z.; Zeng, L.; Zhao, Y.

2017-08-01

Low-wavenumber density fluctuations exhibit unique characteristics during the current ramp-up phase of ITER-like discharges that can partially explain the challenges of correctly modeling transport behavior and predicting global plasma parameters during this period. A strong interaction takes place between the evolving transport, safety factor (q) and kinetic profiles as well as the appearance and evolution of low-order rational surfaces. Density fluctuations from 0.75  <  ρ  <  0.9 are transiently reduced to exceptionally low levels during early times and from 0.8  <  ρ  <  0.9 at late times in the ramp-up in a manner that is different from behavior observed during steady-state plasma conditions with similar values of q 95. Turbulence is suppressed as low-order-rational q-surfaces enter the plasma; the local electron temperature likewise exhibits transient increases during these periods of reduced fluctuations indicating changes in transport that impact temperature and consequently the evolution of current density and plasma inductance. These observations can explain discrepancies between CORSICA modelling and the higher electron temperature found previously over the outer half radius. Comparison of turbulence properties with time-varying linear growth rates with GYRO and GENE demonstrate qualitative consistency with measured fluctuation levels, but calculations don’t exhibit reduced growth rates near low-order rational surfaces, which is inconsistent with experimental observations. This indicates a mechanism that can contribute to reconciling observed turbulence behavior with transport models, allowing for the development of more accurate predictive tools.

The Earth's missing lead may not be in the core.

PubMed

Lagos, M; Ballhaus, C; Münker, C; Wohlgemuth-Ueberwasser, C; Berndt, J; Kuzmin, Dmitry V

2008-11-06

Relative to the CI chondrite class of meteorites (widely thought to be the 'building blocks' of the terrestrial planets), the Earth is depleted in volatile elements. For most elements this depletion is thought to be a solar nebular signature, as chondrites show depletions qualitatively similar to that of the Earth. On the other hand, as lead is a volatile element, some Pb may also have been lost after accretion. The unique (206)Pb/(204)Pb and (207)Pb/(204)Pb ratios of the Earth's mantle suggest that some lead was lost about 50 to 130 Myr after Solar System formation. This has commonly been explained by lead lost via the segregation of a sulphide melt to the Earth's core, which assumes that lead has an affinity towards sulphide. Some models, however, have reconciled the Earth's lead deficit with volatilization. Whichever model is preferred, the broad coincidence of U-Pb model ages with the age of the Moon suggests that lead loss may be related to the Moon-forming impact. Here we report partitioning experiments in metal-sulphide-silicate systems. We show that lead is neither siderophile nor chalcophile enough to explain the high U/Pb ratio of the Earth's mantle as being a result of lead pumping to the core. The Earth may have accreted from initially volatile-depleted material, some lead may have been lost to degassing following the Moon-forming giant impact, or a hidden reservoir exists in the deep mantle with lead isotope compositions complementary to upper-mantle values; it is unlikely though that the missing lead resides in the core.

Assessing tinnitus and prospective tinnitus therapeutics using a psychophysical animal model.

PubMed

Bauer, C A; Brozoski, T J

2001-03-01

Subjective tinnitus is a common and often debilitating disorder that is difficult to study because it is a perceptual state without an objective stimulus correlate. Studying tinnitus in humans is further complicated by the heterogeneity of tinnitus quality, severity, and associated hearing loss. As a consequence, the pathophysiology of tinnitus is poorly understood and treatments are often unsuccessful. In the present study, an animal psychophysical model was developed to reflect several features of tinnitus observed in humans. Chronic tinnitus was induced in rats by a single intense unilateral exposure to noise. The tinnitus was measured using a psychophysical procedure, which required the animals to discriminate between auditory test stimuli consisting of tones, noise, and 0 dB. Tinnitus was indicated by a frequency-specific shift in discrimination functions with respect to control subjects not exposed to noise. The psychophysical consequences of the noise exposure were best explained by a tinnitus hypothesis and could not be explained easily by other consequences of noise exposure such as hearing loss. The qualitative features of the tinnitus were determined and related to the duration of noise exposure and the associated cochlear trauma. The tinnitus was found to persist and intensify over 17 months of testing. Finally, the tinnitus was reversibly attenuated by treatment with gabapentin, a GABA agonist. It was concluded that this model reflected several features of human tinnitus, such as its tonality and persistence, and could be useful as a screen for potential therapeutics as well as a tool to help unravel the pathophysiology of the disorder of phantom auditory perception.

Asymmetric nanowire SQUID: Linear current-phase relation, stochastic switching, and symmetries

NASA Astrophysics Data System (ADS)

Murphy, A.; Bezryadin, A.

2017-09-01

We study nanostructures based on two ultrathin superconducting nanowires connected in parallel to form a superconducting quantum interference device (SQUID). The measured function of the critical current versus magnetic field, IC(B ) , is multivalued, asymmetric, and its maxima and minima are shifted from the usual integer and half integer flux quantum points. We also propose a low-temperature-limit model which generates accurate fits to the IC(B ) functions and provides verifiable predictions. The key assumption of our model is that each wire is characterized by a sample-specific critical phase ϕC defined as the phase difference at which the supercurrent in the wire is the maximum. For our nanowires ϕC is much greater than the usual π /2 , which makes a qualitative difference in the behavior of the SQUID. The nanowire current-phase relation is assumed linear, since the wires are much longer than the coherence length. The model explains single-valuedness regions where only one vorticity value nv is stable. Also, it predicts regions where multiple vorticity values are stable because the Little-Parks (LP) diamonds, which describe the region of stability for each winding number nv in the current-field diagram, can overlap. We also observe and explain regions in which the standard deviation of the switching current is independent of the magnetic field. We develop a technique that allows a reliable detection of hidden phase slips and use it to determine the boundaries of the LP diamonds even at low currents where IC(B ) is not directly measurable.

A CFBPN Artificial Neural Network Model for Educational Qualitative Data Analyses: Example of Students' Attitudes Based on Kellerts' Typologies

ERIC Educational Resources Information Center

Yorek, Nurettin; Ugulu, Ilker

2015-01-01

In this study, artificial neural networks are suggested as a model that can be "trained" to yield qualitative results out of a huge amount of categorical data. It can be said that this is a new approach applied in educational qualitative data analysis. In this direction, a cascade-forward back-propagation neural network (CFBPN) model was…

Mixed methods research design for pragmatic psychoanalytic studies.

PubMed

Tillman, Jane G; Clemence, A Jill; Stevens, Jennifer L

2011-10-01

Calls for more rigorous psychoanalytic studies have increased over the past decade. The field has been divided by those who assert that psychoanalysis is properly a hermeneutic endeavor and those who see it as a science. A comparable debate is found in research methodology, where qualitative and quantitative methods have often been seen as occupying orthogonal positions. Recently, Mixed Methods Research (MMR) has emerged as a viable "third community" of research, pursuing a pragmatic approach to research endeavors through integrating qualitative and quantitative procedures in a single study design. Mixed Methods Research designs and the terminology associated with this emerging approach are explained, after which the methodology is explored as a potential integrative approach to a psychoanalytic human science. Both qualitative and quantitative research methods are reviewed, as well as how they may be used in Mixed Methods Research to study complex human phenomena.

Conducting qualitative research in the British Armed Forces: theoretical, analytical and ethical implications.

PubMed

Finnegan, Alan

2014-06-01

The aim of qualitative research is to produce empirical evidence with data collected through means such as interviews and observation. Qualitative research encourages diversity in the way of thinking and the methods used. Good studies produce a richness of data to provide new knowledge or address extant problems. However, qualitative research resulting in peer review publications within the Defence Medical Services (DMS) is a rarity. This article aims to help redress this balance by offering direction regarding qualitative research in the DMS with a focus on choosing a theoretical framework, analysing the data and ethical approval. Qualitative researchers need an understanding of the paradigms and theories that underpin methodological frameworks, and this article includes an overview of common theories in phenomenology, ethnography and grounded theory, and their application within the military. It explains qualitative coding: the process used to analyse data and shape the analytical framework. A popular four phase approach with examples from an operational nursing research study is presented. Finally, it tackles the issue of ethical approval for qualitative studies and offers direction regarding the research proposal and participant consent. The few qualitative research studies undertaken in the DMS have offered innovative insights into defence healthcare providing information to inform and change educational programmes and clinical practice. This article provides an extra resource for clinicians to encourage studies that will improve the operational capability of the British Armed Forces. It is anticipated that these guidelines are transferable to research in other Armed Forces and the military Veterans population. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

[The positioning of nursing research in the academic studies: the origin and development of qualitative and quantitative studies].

PubMed

Lu, Pei-Pei; Ting, Shing-Shiang; Chen, Mei-Ling; Tang, Woung-Ru

2005-12-01

The purpose of this study is to discuss the historical context of qualitative and quantitative research so as to explain the principle of qualitative study and examine the positioning of nursing research within academic study as a whole. This paper guides the readers towards the historical context from empirical science, discusses the influences of qualitative and quantitative research on nursing research, then investigates the nature of research paradigms, examines the positioning of nursing research, which includes the characteristics of fields such as natural science, humanity and social studies, and science, and lastly, presents the research standard proposed by Yardley in 2000. The research paradigms include Positivism, Postpositivism, Criticism, and Constructivism, which can be compared with Ontology, Epistemology, and Methodology. The nature of the paradigm is to determine the assumption of the paradigm on the basis of Ontology, Epistemology, and Methodology. The paradigm determines how the researcher views the world and decides on what to answer, how to research, and how to answer. The difference in academic environment is reflected in the long-term dialogue between qualitative and quantitative studies, as well as the standard for criticism. This paper introduces the method of evaluation of the quality of qualitative study proposed by Yardley in 2002, namely the sensitivity of the context, the promise and conscientiousness, transparency and consistency, influence and significance. The paper is intended to provide a guideline for readers in evaluating the quality of qualitative study.

Nurturing the Imagination: Creativity Processes and Innovative Qualitative Research Projects

ERIC Educational Resources Information Center

Mulvihill, Thalia M.; Swaminathan, Raji

2012-01-01

This article explores the creativity processes involved in designing and analyzing innovative qualitative research projects and evaluates examples of recent models and typologies that illustrate a variety of ways to approach qualitative inquiry. Using Gardner's Five Minds (2006) typology, Boyer's Model of Scholarship (1997) and Bloom's Taxonomy of…

Show what you know and deal with stress yourself: a qualitative interview study of medical interns' perceptions of stress and gender.

PubMed

Verdonk, Petra; Räntzsch, Viktoria; de Vries, Remko; Houkes, Inge

2014-05-17

Medical students report high stress levels and in particular, the clinical phase is a demanding one. The field of medicine is still described as having a patriarchal culture which favors aspects like a physicians' perceived certainty and rationalism. Also, the Effort-Recovery Model explains stress as coming from a discrepancy between job demands, job control, and perceived work potential. Gendered differences in stress are reported, but not much is known about medical interns' perceptions of how gender plays in relation to stress. The aim of this study is to explore how medical interns experience and cope with stress, as well as how they reflect on the gendered aspects of stress. In order to do this, we have performed a qualitative study. In 2010-2011, semi-structured qualitative interviews were conducted with seventeen medical interns across all three years of the Masters programme (6 male, 11 female) at a Dutch medical school. The interview guide is based on gender theory, the Effort-Recovery Model, and empirical literature. Transcribed interviews have been analyzed thematically. First, stress mainly evolves from having to prove one's self and show off competencies and motivation ("Show What You Know…"). Second, interns seek own solutions for handling stress because it is not open for discussion (… "And Deal With Stress Yourself"). Patient encounters are a source of pride and satisfaction rather than a source of stress. But interns report having to present themselves as 'professional and self-confident', remaining silent about experiencing stress. Female students are perceived to have more stress and to study harder in order to live up to expectations. The implicit message interns hear is to remain silent about insecurities and stress, and, in particular, female students might face disadvantages. Students who feel less able to manifest the 'masculine protest' may benefit from a culture that embraces more collaborative styles, such as having open conversation about stress.

High-Dose Benzodiazepine Dependence: A Qualitative Study of Patients’ Perceptions on Initiation, Reasons for Use, and Obtainment

PubMed Central

Liebrenz, Michael; Schneider, Marcel; Buadze, Anna; Gehring, Marie-Therese; Dube, Anish; Caflisch, Carlo

2015-01-01

Background High-dose benzodiazepine (BZD) dependence is associated with a wide variety of negative health consequences. Affected individuals are reported to suffer from severe mental disorders and are often unable to achieve long-term abstinence via recommended discontinuation strategies. Although it is increasingly understood that treatment interventions should take subjective experiences and beliefs into account, the perceptions of this group of individuals remain under-investigated. Methods We conducted an exploratory qualitative study with 41 adult subjects meeting criteria for (high-dose) BZD-dependence, as defined by ICD-10. One-on-one in-depth interviews allowed for an exploration of this group’s views on the reasons behind their initial and then continued use of BZDs, as well as their procurement strategies. Mayring’s qualitative content analysis was used to evaluate our data. Results In this sample, all participants had developed explanatory models for why they began using BZDs. We identified a multitude of reasons that we grouped into four broad categories, as explaining continued BZD use: (1) to cope with symptoms of psychological distress or mental disorder other than substance use, (2) to manage symptoms of physical or psychological discomfort associated with somatic disorder, (3) to alleviate symptoms of substance-related disorders, and (4) for recreational purposes, that is, sensation-seeking and other social reasons. Subjects often considered BZDs less dangerous than other substances and associated their use more often with harm reduction than as recreational. Specific obtainment strategies varied widely: the majority of participants oscillated between legal and illegal methods, often relying on the black market when faced with treatment termination. Conclusions Irrespective of comorbidity, participants expressed a clear preference for medically related explanatory models for their BZD use. We therefore suggest that clinicians consider patients’ motives for long-term, high-dose BZD use when formulating treatment plans for this patient group, especially since it is known that individuals are more compliant with approaches they perceive to be manageable, tolerable, and effective. PMID:26556055

Perceptions on use of home telemonitoring in patients with long term conditions - concordance with the Health Information Technology Acceptance Model: a qualitative collective case study.

PubMed

Middlemass, Jo B; Vos, Jolien; Siriwardena, A Niroshan

2017-06-26

Health information technology (HIT) may be used to improve care for increasing numbers of older people with long term conditions (LTCs) who make high demands on health and social care services. Despite its potential benefits for reducing disease exacerbations and hospitalisations, HIT home monitoring is not always accepted by patients. Using the Health Information Technology Acceptance Model (HITAM) this qualitative study examined the usefulness of the model for understanding acceptance of HIT in older people (≥60 years) participating in a RCT for older people with Chronic Obstructive Pulmonary Disease (COPD) and associated heart diseases (CHROMED). An instrumental, collective case study design was used with qualitative interviews of patients in the intervention arm of CHROMED. These were conducted at two time points, one shortly after installation of equipment and again at the end of (or withdrawal from) the study. We used Framework Analysis to examine how well the HITAM accounted for the data. Participants included 21 patients aged between 60-99 years and their partners or relatives where applicable. Additional concepts for the HITAM for older people included: concerns regarding health professional access and attachment; heightened illness anxiety and desire to avoid continuation of the 'sick-role'. In the technology zone, HIT self-efficacy was associated with good organisational processes and informal support; while ease of use was connected to equipment design being suitable for older people. HIT perceived usefulness was related to establishing trends in health status, detecting early signs of infection and potential to self-manage. Due to limited feedback to users opportunities to self-manage were reduced. HITAM helped understand the likelihood that older people with LTCs would use HIT, but did not explain how this might result in improved self-management. In order to increase HIT acceptance among older people, equipment design and organisational factors need to be considered. ClinicalTrials.gov Identifier: NCT01960907 October 9 2013 (retrospectively registered) Clinical tRials fOr elderly patients with MultiplE Disease (CHROMED). Start date October 2012, end date March 2016. Date of enrolment of the first participant was February 2013.

An intervention to improve interprofessional collaboration and communications: a comparative qualitative study.

PubMed

Rice, Kathleen; Zwarenstein, Merrick; Conn, Lesley Gotlib; Kenaszchuk, Chris; Russell, Ann; Reeves, Scott

2010-07-01

Interprofessional communication and collaboration are promoted by policymakers as fundamental building blocks for improving patient safety and meeting the demands of increasingly complex care. This paper reports qualitative findings of an interprofessional intervention designed to improve communication and collaboration between different professions in general internal medicine (GIM) hospital wards in Canada. The intervention promoted self-introduction by role and profession to a collaborating colleague in relation to the shared patient, a question or communication regarding the patient, to be followed by an explicit request for feedback from the partner professional. Implementation and uptake of the intervention were evaluated using qualitative methods, including 90 hours of ethnographic observations and interviews collected in both intervention and comparison wards. Documentary data were also collected and analysed. Fieldnotes and interviews were transcribed and analysed thematically. Our findings suggested that the intervention did not produce the anticipated changes in communication and collaboration between health professionals, and allowed us to identify barriers to the implementation of effective collaboration interventions. Despite initially offering verbal support, senior physicians, nurses, and allied health professionals minimally explained the intervention to their junior colleagues and rarely role-modelled or reiterated support for it. Professional resistances as well as the fast paced, interruptive environment reduced opportunities or incentive to enhance restrictive interprofessional relationships. In a healthcare setting where face-to-face spontaneous interprofessional communication is not hostile but is rare and impersonal, the perceived benefits of improvement are insufficient to implement simple and potentially beneficial communication changes, in the face of habit, and absence of continued senior clinician and management support.