Theoretical and simulation studies of seeding methods

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

Pellegrini, Claudio

We report the theoretical and experimental studies done with the support of DOE-Grant DE-SC0009983 to increase an X-ray FEL peak power from the present level of 20 to 40 GW to one or more TW by seeding, undulator tapering and using the new concept of the Double Bunch FEL.

Vertical distribution of microphysical properties in radiation fogs - A case study

NASA Astrophysics Data System (ADS)

Egli, S.; Maier, F.; Bendix, J.; Thies, B.

2015-01-01

The present study investigates the validity of a theoretical liquid water content (LWC) profile in fog layers currently used for satellite based ground fog detection, with a special focus on the temporal dynamics during fog life cycle. For this purpose, LWC profiles recorded during two different fog events by means of a tethered balloon borne measurement system are presented and discussed. The results indicate a good agreement in trend and gradient between measured and theoretical LWC profiles during the mature stage of the fog life cycle. The profile obtained during the dissipation stage shows less accordance with the theoretical profile. To improve the agreement between theoretical and measured LWC profiles, the evolutionary stages during the fog life cycle should be incorporated. However, the variability within the prenoted measurements points out that more LWC profiles during a great variety of different fog events have to be collected for a well-justified adaptation of the theoretical LWC profile, considering fog life cycle phases in the future. In general, this underlines the existing knowledge gap regarding the vertical distribution of microphysical properties in natural fogs.

Proceedings of the Meeting of the Study Committee of International Federation for Documentation "Research on the Theoretical Basis of Information" (Moscow, 24-26 February 1970).

ERIC Educational Resources Information Center

All-Union Inst. for Scientific and Technical Information, Moscow (USSR).

Reports given before the Committee on "Research on the Theoretical Basis of Information" of the International Federation for Documentation (FID/RI) are presented unaltered and unabridged in English or in Russian -- the language of their presentation. Each report is accompanied by an English or Russian resume. Generally, only original…

Studying the complex spectral line profiles in the spectra of hot emission stars and quasars .

NASA Astrophysics Data System (ADS)

Danezis, E.; Lyratzi, E.; Antoniou, A.; Popović, L. Č.; Dimitrijević, M. S.

Some Hot Emission Stars and AGNs present peculiar spectral line profiles which are due to DACs and SACs phenomena. The origin and the mechanisms which are responsible for the creation of DACs/SACs is an important problem that has been studied by many researchers. This paper is a review of our efforts to study the origin and the mechanisms of these phenomena. At first we present a theoretic ad hoc picture for the structure of the plasma that surrounds the specific category of hot emission stars that present DACs or SACs. Then we present the mathematical model that we constructed, which is based on the properties of the above ad hoc theoretical structure. Finally, we present some results from our statistical studies that prove the consistency of our model with the classical physical theory.

The Convergence of Institutional Logics on the Community College Sector and the Normalization of Emotional Labor: A New Theoretical Approach for Considering the Community College Faculty Labor Expectations

ERIC Educational Resources Information Center

Gonzales, Leslie D.; Ayers, David F.

2018-01-01

Little empirical research has systematically focused on, or interrogated, the labor expectations set forth for community college faculty. Thus, in this paper, we present a theoretical argument, which we formed by (re) reading several community college focused studies through various theoretical lenses. Ultimately, we merged two…

Abduction, Deduction and Induction: Can These Concepts Be Used for an Understanding of Methodological Processes in Interpretative Case Studies?

ERIC Educational Resources Information Center

Åsvoll, Håvard

2014-01-01

Within the area of interpretative case studies, there appears to be a vast amount of literature about theoretical interpretations as the main analytical strategy. In light of this theoretically based strategy in case studies, this article presents an extended perspective based on Charles Sanders Peirce's concepts of abduction, deduction and…

Electronic properties of diphenyl-s-tetrazine and some related oligomers. An spectroscopic and theoretical study

NASA Astrophysics Data System (ADS)

Moral, Mónica; García, Gregorio; Peñas, Antonio; Garzón, Andrés; Granadino-Roldán, José M.; Melguizo, Manuel; Fernández-Gómez, Manuel

2012-10-01

This work presents a theoretical and spectroscopic study on the electronic and structural properties of the diphenyl-s-tetrazine molecule (Ph2Tz) and some oligomeric derivatives. Ph2Tz was synthesized through a variation of Pinner-type reaction which uses N-acetylcysteine as catalyst. Insight into the structure and electronic properties of the title compound was obtained through IR, Raman, UV-Vis spectra in different solvents, and theoretical calculations. Theoretical studies have been extended to different n-mers derivatives up to an ideal molecular wire through the oligomeric approximation, predicting this way electronic properties such as LUMO energy levels, electron affinity and reorganization energy in order to assess their possible applications in molecular electronics.

Functional Literacy: Theoretical Issues and Educational Implications. Studies in Written Language and Literacy, Volume 1.

ERIC Educational Resources Information Center

Verhoeven, Ludo, Ed.

Opening up new perspectives in the study of literacy, this book presents 25 essays that bring together current research findings from linguistics, psychology, sociology, and anthropology. Essays in the book discuss theoretical questions related to the definition and modeling of the construct of functional literacy; the notion of literacy…

The Influence of Romantic Attachment and Intimate Partner Violence on Non-Suicidal Self-Injury in Young Adults

ERIC Educational Resources Information Center

Levesque, Christine; Lafontaine, Marie-France; Bureau, Jean-Francois; Cloutier, Paula; Dandurand, Cathy

2010-01-01

Several theoretical models for non-suicidal self-injury (NSSI) have been proposed. Despite an abundance of theoretical speculation, few empirical studies have examined the impact of intimate relationship functioning on NSSI. The present study examines the influence of romantic attachment and received intimate partner violence (physical,…

Applying a Conceptual Design Framework to Study Teachers' Use of Educational Technology

ERIC Educational Resources Information Center

Holmberg, Jörgen

2017-01-01

Theoretical outcomes of design-based research (DBR) are often presented in the form of local theory design principles. This article suggests a complementary theoretical construction in DBR, in the form of a "design framework" at a higher abstract level, to study and inform educational design with ICT in different situated contexts.…

Experimental study of microwave photon statistics under parametric amplification from a single-mode thermal state in a cavity

NASA Astrophysics Data System (ADS)

Galeazzi, G.; Lombardi, A.; Ruoso, G.; Braggio, C.; Carugno, G.; Della Valle, F.; Zanello, D.; Dodonov, V. V.

2013-11-01

In this paper we present theoretical and experimental studies of the modifications of the thermal spectrum inside a microwave resonator due to a parametric amplification process. Both the degenerate and nondegenerate amplifiers are discussed. Theoretical calculations are compared with measurements performed with a microwave cavity parametric amplifier.

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

Gómez, A. M., E-mail: amgomezl-1@uqvirtual.edu.co; Torres, D. A., E-mail: datorresg@unal.edu.co

The experimental study of nuclear magnetic moments, using the Transient Field technique, makes use of spin-orbit hyperfine interactions to generate strong magnetic fields, above the kilo-Tesla regime, capable to create a precession of the nuclear spin. A theoretical description of such magnetic fields is still under theoretical research, and the use of parametrizations is still a common way to address the lack of theoretical information. In this contribution, a review of the main parametrizations utilized in the measurements of Nuclear Magnetic Moments will be presented, the challenges to create a theoretical description from first principles will be discussed.

Scaffolding for Argumentation in Hypothetical and Theoretical Biology Concepts

ERIC Educational Resources Information Center

Weng, Wan-Yun; Lin, Yu-Ren; She, Hsiao-Ching

2017-01-01

The present study investigated the effects of online argumentation scaffolding on students' argumentation involving hypothetical and theoretical biological concepts. Two types of scaffolding were developed in order to improve student argumentation: continuous scaffolding and withdraw scaffolding. A quasi-experimental design was used with four…

A Theoretical Model for the Practice of Residential Treatment.

ERIC Educational Resources Information Center

Miskimins, R. W.

1990-01-01

Presents theoretical model describing practice of psychiatric residential treatment for children and adolescents. Emphasis is on 40 practice principles, guiding concepts which dictate specific treatment techniques and administrative procedures for Southern Oregon Adolescent Study and Treatment Center. Groups principles into six clusters: program…

Teachers' Perspectives on Principal Mistreatment

ERIC Educational Resources Information Center

Blase, Joseph; Blase, Jo

2006-01-01

Although there is some important scholarly work on the problem of workplace mistreatment/abuse, theoretical or empirical work on abusive school principals is nonexistent. Symbolic interactionism was the theoretical structure for the present study. This perspective on social research is founded on three primary assumptions: (1) individuals act…

Some new ideas for the study of the complex spectral line profiles of hot emission stars and quasars

NASA Astrophysics Data System (ADS)

Danezis, E.

2013-01-01

Some Hot Emission Stars and AGNs present peculiar spectral line profiles which are due to DACs and SACs phenomena. The origin and the mechanisms which are responsible for the creation of DACs/SACs is an important problem that has been studied by many researchers. This paper is a review of our efforts to study the origin and the mechanisms of these phenomena. At first we present a theoretic ad hoc picture for the structure of the plasma that surrounds the specific category of hot emission stars that present DACs or SACs. Then we present the mathematical model that we constructed, which is based on the properties of the above ad hoc theoretical structure. Finally, we present some results from our statistical studies that prove the consistency of our model with the classical physical theory.

A Study on the Security Levels of Spread-Spectrum Embedding Schemes in the WOA Framework.

PubMed

Wang, Yuan-Gen; Zhu, Guopu; Kwong, Sam; Shi, Yun-Qing

2017-08-23

Security analysis is a very important issue for digital watermarking. Several years ago, according to Kerckhoffs' principle, the famous four security levels, namely insecurity, key security, subspace security, and stego-security, were defined for spread-spectrum (SS) embedding schemes in the framework of watermarked-only attack. However, up to now there has been little application of the definition of these security levels to the theoretical analysis of the security of SS embedding schemes, due to the difficulty of the theoretical analysis. In this paper, based on the security definition, we present a theoretical analysis to evaluate the security levels of five typical SS embedding schemes, which are the classical SS, the improved SS (ISS), the circular extension of ISS, the nonrobust and robust natural watermarking, respectively. The theoretical analysis of these typical SS schemes are successfully performed by taking advantage of the convolution of probability distributions to derive the probabilistic models of watermarked signals. Moreover, simulations are conducted to illustrate and validate our theoretical analysis. We believe that the theoretical and practical analysis presented in this paper can bridge the gap between the definition of the four security levels and its application to the theoretical analysis of SS embedding schemes.

Psychometric properties and Confirmatory structure of the Strengths and difficulties questionnaire in a sample of adolescents in Nigeria.

PubMed

Akpa, Onoja M; Afolabi, Rotimi F; Fowobaje, Kayode R

Though the SDQ has been used in selected studies in Nigeria, its theoretical structure has not been fully and appropriately investigated in the setting. The present study employs Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) to investigate the theoretical structure of the self-reported version of the SDQ in a sample of adolescents in Benue state, Nigeria. A total of 1,244 adolescents from different categories of secondary schools in Makurdi and Vandekya Local government areas of Benue state participated in the study. Preliminary data analyses were performed using descriptive statistics while the theoretical structure of the SDQ was assessed using EFA and CFA. Model fits were assessed using Chi-square test and other fit indices at 5% significance level. Participants were 14.19±2.45 (Vandekya) and 14.19±2.45 (Makurdi) years old. Results of the EFA and CFA revealed a 3-factor oblique model as the best model for the sample of adolescents studied ( χ 2 / df =2.20, p<0.001) with all fit indices yielding better results. A correlated 3-factor model fits the present data better than the 5-factor theoretical model of the SDQ. The use of the original 5-factor model of the SDQ in the present setting should be interpreted with caution.

Mentoring Trainee Music Teachers: Beyond Apprenticeship or Reflection

ERIC Educational Resources Information Center

Cain, Tim

2007-01-01

This article explores the theoretical concepts of "apprenticeship" and "reflection" in Initial Teacher Education music mentoring. It presents two case studies of Secondary music mentoring and relates these to the theoretical concepts. The article argues that a more integrated view of music mentoring might be provided with…

Fluctuations and the QCD Phase Diagram

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

Koch, Volker; Bzdak, Adam

2016-07-01

Here, we will discuss how the study of various fluctuation observables may be used to explore the phase diagram of the strong interaction. Furthermore, we will briefly summarize the present study of experimental and theoretical research in this area. We will then discuss various corrections and issues which need to be understood and applied for a meaningful comparison of experimental measurements with theoretical predictions.

Flexible bent rod model with a saturating induced dipole moment to study the electric linear dichroism of DNA fragments

NASA Astrophysics Data System (ADS)

Bertolotto, Jorge A.; Umazano, Juan P.

2016-06-01

In the present work we make a theoretical study of the steady state electric linear dichroism of DNA fragments in aqueous solution. The here developed theoretical approach considers a flexible bent rod model with a saturating induced dipole moment. The electric polarizability tensor of bent DNA fragments is calculated considering a phenomenological model which theoretical and experimental backgroung is presented here. The model has into account the electric polarizability longitudinal and transversal to the macroion. Molecular flexibility is described using an elastic potential. We consider DNA fragments originally bent with bending fluctuations around an average bending angle. The induced dipole moment is supposed constant once the electric field strength grows up at critical value. To calculate the reduced electric linear dichroism we determine the optical factor considering the basis of the bent DNA perpendicular to the molecular axis. The orientational distribution function has into account the anisotropic electric properties and the molecule flexibility. We applied the present theoretical background to fit electric dichroism experimental data of DNA fragments reported in the bibliography in a wide range of molecular weight and electric field. From these fits, values of DNA physical properties are estimated. We compare and discuss the results here obtained with the theoretical and experimental data presented by other authors. The original contributions of this work are: the inclusion of the transversal electric polarizability saturating with the electric field, the description of the electric properties with an electric polarizability tensor dependant on the bending angle and the use of an arc model originally bent.

Explaining Teacher-Student Interactions in Early Childhood: An Interpersonal Theoretical Approach

ERIC Educational Resources Information Center

Thijs, Jochem; Koomen, Helma; Roorda, Debora; ten Hagen, Judith

2011-01-01

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

An e-Learning Theoretical Framework

ERIC Educational Resources Information Center

Aparicio, Manuela; Bacao, Fernando; Oliveira, Tiago

2016-01-01

E-learning systems have witnessed a usage and research increase in the past decade. This article presents the e-learning concepts ecosystem. It summarizes the various scopes on e-learning studies. Here we propose an e-learning theoretical framework. This theory framework is based upon three principal dimensions: users, technology, and services…

Implicit Theoretical Leadership Frameworks of Higher Education Administrators.

ERIC Educational Resources Information Center

Lees, Kimberly; And Others

Colleges and universities have a unique organizational culture that influences the decision-making processes used by leaders of higher education. This paper presents findings of a study that attempted to identify the theoretical frameworks that administrators of higher education use to guide their decision-making processes. The following…

A beginner's guide to writing the nursing conceptual model-based theoretical rationale.

PubMed

Gigliotti, Eileen; Manister, Nancy N

2012-10-01

Writing the theoretical rationale for a study can be a daunting prospect for novice researchers. Nursing's conceptual models provide excellent frameworks for placement of study variables, but moving from the very abstract concepts of the nursing model to the less abstract concepts of the study variables is difficult. Similar to the five-paragraph essay used by writing teachers to assist beginning writers to construct a logical thesis, the authors of this column present guidelines that beginners can follow to construct their theoretical rationale. This guide can be used with any nursing conceptual model but Neuman's model was chosen here as the exemplar.

The Self-Presentation Motives for Physical Activity Questionnaire: Instrument Development and Preliminary Construct Validity Evidence.

PubMed

Howle, Timothy C; Dimmock, James A; Whipp, Peter R; Jackson, Ben

2015-06-01

With the aim of advancing the literature on impression management in physical activity settings, we developed a theoretically derived 2 by 2 instrument that was designed to measure different types of context-specific self-presentation motives. Following item generation and expert review (Study 1), the instrument was completed by 206 group exercise class attendees (Study 2) and 463 high school physical education students (Study 3). Our analyses supported the intended factor structure (i.e., reflecting acquisitive-agentic, acquisitive-communal, protective-agentic, and protective-communal motives). We found some support for construct validity, and the self-presentation motives were associated with variables of theoretical and applied interest (e.g., impression motivation and construction, social anxiety, social and achievement goals, efficacy beliefs, engagement). Taken together, the results indicate that the Self-presentation Motives for Physical Activity Questionnaire (SMPAQ) may be useful for measuring various types of self-presentation motives in physical activity settings.

Spectroscopic Study of Neon Z-Pinch Plasma for Sodium-Neon Photopumping Experiments

DTIC Science & Technology

1992-01-06

enhancement of the 11-A radiation from the n=4 level of neon when the sodium pump was present. For the 25-GV pump power, theoretical calculations predict...when the neon plasma is photopumped. Extensive theoretical analysis has been devoted to establishing the appropriate conditions for these plasmas. 5 ,44...producing thermonuclear neutrons. 63-65 Extensive theoretical modeling of the stability of these plasmas has guided this work.66 An imploding-liner Z

Structural characterisation of some vanillic Mannich bases: Experimental and theoretical study

NASA Astrophysics Data System (ADS)

Petrović, Vladimir P.; Simijonović, Dušica; Novaković, Sladjana B.; Bogdanović, Goran A.; Marković, Svetlana; Petrović, Zorica D.

2015-10-01

In this paper, synthesis and structural determination of 2-[1-(N-4-fluorophenylamino)-1-(4-hydroxy-3-methoxyphenyl)]methylcyclohexanone (MB-F) is presented. To determine the structure of this new compound, IR and NMR spectral characterisation was performed experimentally and theoretically. Simulation of spectral data was carried out using three functionals: B3LYP, B3LYP-D2, and M06-2X. The results obtained for MB-F were compared to those attained for similar, known compound 2-[1-(N-phenylamino)-1-(4-hydroxy-3-methoxyphenyl)]methylcyclohexanone (MB-H), whose crystal structure is presented here. Taking into account all experimental and theoretical findings, the structure of MB-F was proposed.

Advanced Numerical and Theoretical Methods for Photonic Crystals and Metamaterials

NASA Astrophysics Data System (ADS)

Felbacq, Didier

2016-11-01

This book provides a set of theoretical and numerical tools useful for the study of wave propagation in metamaterials and photonic crystals. While concentrating on electromagnetic waves, most of the material can be used for acoustic (or quantum) waves. For each presented numerical method, numerical code written in MATLAB® is presented. The codes are limited to 2D problems and can be easily translated in Python or Scilab, and used directly with Octave as well.

A variational data assimilation system for the range dependent acoustic model using the representer method: Theoretical derivations.

PubMed

Ngodock, Hans; Carrier, Matthew; Fabre, Josette; Zingarelli, Robert; Souopgui, Innocent

2017-07-01

This study presents the theoretical framework for variational data assimilation of acoustic pressure observations into an acoustic propagation model, namely, the range dependent acoustic model (RAM). RAM uses the split-step Padé algorithm to solve the parabolic equation. The assimilation consists of minimizing a weighted least squares cost function that includes discrepancies between the model solution and the observations. The minimization process, which uses the principle of variations, requires the derivation of the tangent linear and adjoint models of the RAM. The mathematical derivations are presented here, and, for the sake of brevity, a companion study presents the numerical implementation and results from the assimilation simulated acoustic pressure observations.

Theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Shu-qing; Feng, Zhong-ying; Liu, Xiao-fei; Gao, Jin-yue

2016-12-01

To obtain the weak signal light detection from the high background noise, we present a theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency. In a three-level Λ -type atomic system in the rubidium D1 line, the bandwidth of the EIT atomic filter is narrowed to ~6.5 \\text{MHz} . And the single peak transmission of the filter can be up to 86% . Moreover, the transmission wavelength can be tuned by changing the coupling light frequency. This theoretical scheme can also be applied to other alkali atomic systems.

When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline-Earth-Metal Acetylides

PubMed Central

Guino-o, Marites A.; Alexander, Jacob S.; McKee, Michael L.; Hope, Håkon; Englich, Ulrich B.

2014-01-01

The synthesis, structural, and spectral characterization as well as a theoretical study of a family of alkaline-earth-metal acetylides provides insights into synthetic access and the structural and bonding characteristics of this group of highly reactive compounds. Based on our earlier communication that reported unusual geometry for a family of triphenylsilyl-substituted alkaline-earth-metal acetylides, we herein present our studies on an expanded family of target derivatives, providing experimental and theoretical data to offer new insights into the intensively debated theme of structural chemistry in heavy alkaline-earth-metal chemistry. PMID:19844925

Theoretical study of local structure for Ni2+ ions at tetragonal sites in K2ZnF4:Ni2+ system.

PubMed

Wang, Su-Juan; Kuang, Xiao-Yu; Lu, Cheng

2008-12-15

A theoretical method for studying the local lattice structure of Ni2+ ions in (NiF6)(4-) coordination complex is presented. Using the ligand-field model, the formulas relating the microscopic spin Hamiltonian parameters with the crystal structure parameters are derived. Based on the theoretical formulas, the 45 x 45 complete energy matrices for d8 (d2) configuration ions in a tetragonal ligand-field are constructed. By diagonalizing the complete energy matrices, the local distortion structure parameters (R perpendicular and R || ) of Ni2+ ions in K2ZnF4:Ni2+ system have been investigated. The theoretical results are accorded well with the experimental values. Moreover, to understand the detailed physical and chemical properties of the fluoroperovskite crystals, the theoretical values of the g factor of K2ZnF4:Ni2+ system at 78 and 290 K are reported first.

Theoretical study of local structure for Ni 2+ ions at tetragonal sites in K 2ZnF 4:Ni 2+ system

NASA Astrophysics Data System (ADS)

Wang, Su-Juan; Kuang, Xiao-Yu; Lu, Cheng

2008-12-01

A theoretical method for studying the local lattice structure of Ni 2+ ions in (NiF 6) 4- coordination complex is presented. Using the ligand-field model, the formulas relating the microscopic spin Hamiltonian parameters with the crystal structure parameters are derived. Based on the theoretical formulas, the 45 × 45 complete energy matrices for d8 ( d2) configuration ions in a tetragonal ligand-field are constructed. By diagonalizing the complete energy matrices, the local distortion structure parameters ( R⊥ and R||) of Ni 2+ ions in K 2ZnF 4:Ni 2+ system have been investigated. The theoretical results are accorded well with the experimental values. Moreover, to understand the detailed physical and chemical properties of the fluoroperovskite crystals, the theoretical values of the g factor of K 2ZnF 4:Ni 2+ system at 78 and 290 K are reported first.

A Theoretical Assessment of Regional Development Effects on the Demand for General Education

ERIC Educational Resources Information Center

Iwahashi, Roki

2007-01-01

This study addresses a prospective aspect of general education: through general education, people obtain information about returns to their future specific education, thereby enabling them to choose fields in which they excel. According to that property of education, this paper presents a theoretical framework as a basis for understanding effects…

Enriching the Theoretical Horizons of Phenomenography, Variation Theory and Learning Studies

ERIC Educational Resources Information Center

Dahlin, Bo

2007-01-01

The aim of this article is to introduce some theoretical frameworks which may develop the research going on within phenomenography and variation theory. Central concepts from the epistemological and cognitive theories of Charles S. Peirce, Niklas Luhmann and Margaret Boden are presented and their implications for phenomenography and variation…

Main rotor free wake geometry effects on blade air loads and response for helicopters in steady maneuvers. Volume 1: Theoretical formulation and analysis of results

NASA Technical Reports Server (NTRS)

Sadler, S. G.

1972-01-01

A mathematical model and computer program were implemented to study the main rotor free wake geometry effects on helicopter rotor blade air loads and response in steady maneuvers. The theoretical formulation and analysis of results are presented.

Analysis of rosen piezoelectric transformers with a varying cross-section.

PubMed

Xue, H; Yang, J; Hu, Y

2008-07-01

We study the effects of a varying cross-section on the performance of Rosen piezoelectric transformers operating with length extensional modes of rods. A theoretical analysis is performed using an extended version of a one-dimensional model developed in a previous paper. Numerical results based on the theoretical analysis are presented.

Sweat Therapy Theory, Practice, and Efficacy

ERIC Educational Resources Information Center

Eason, Allen; Colmant, Stephen; Winterowd, Carrie

2009-01-01

The purpose of this article is to examine the potential application of sweat rituals to group counseling, adventure therapy, and other forms of group work by describing a theoretical model for how sweat rituals work and presenting the results of a randomized comparative outcome study on the efficacy of sweat therapy. The theoretical model proposes…

Measuring Experiential Avoidance: A Preliminary Test of a Working Model

ERIC Educational Resources Information Center

Hayes, Steven C.; Strosahl, Kirk; Wilson, Kelly G.; Bissett, Richard T.; Pistorello, Jacqueline; Toarmino, Dosheen; Polusny, Melissa A.; Dykstra, Thane A.; Batten, Sonja V.; Bergan, John; Stewart, Sherry H.; Zvolensky, Michael J.; Eifert, Georg H.; Bond, Frank W.; Forsyth, John P.; Karekla, Maria; Mccurry, Susan M.

2004-01-01

The present study describes the development of a short, general measure of experiential avoidance, based on a specific theoretical approach to this process. A theoretically driven iterative exploratory analysis using structural equation modeling on data from a clinical sample yielded a single factor comprising 9 items. A fully confirmatory factor…

Interrelations in Cognition and Affect in Infancy: A Comparison of Piagetian, Psychoanalytic, and Eriksonian Theories.

ERIC Educational Resources Information Center

Mowbray, Carol T.

This paper presents a theoretical and empirical analysis of Piagetian and psychoanalytic theories of infancy to establish the developmental relationships between cognition and affect. Theoretical points of similarity and dissimilarity are cited. Relevant reasearch studies (Bell, Gouin-Decarie, Fraiberg) are reviewed in an attempt to resolve…

Mode Deactivation Therapy (MDT) Family Therapy: A Theoretical Case Analysis

ERIC Educational Resources Information Center

Apsche, J. A.; Ward Bailey, S. R.

2004-01-01

This case study presents a theoretical analysis of implementing mode deactivation therapy (MDT) (Apsche & Ward Bailey, 2003) family therapy with a 13 year old Caucasian male. MDT is a form of cognitive behavioral therapy (CBT) that combines the balance of dialectical behavior therapy (DBT) (Linehan, 1993), the importance of perception from…

Inertial confinement fusion for energy: overview of the ongoing experimental, theoretical and numerical studies

NASA Astrophysics Data System (ADS)

Jacquemot, S.

2017-10-01

This paper provides an overview of the results presented at the 26th IAEA Fusion Energy Conference in the field of inertial confinement fusion for energy, covering its various experimental, numerical/theoretical and technological facets, as well as the different paths towards ignition that are currently followed worldwide.

Theoretical and Experimental Studies of the Electro-Optic Effect: Toward a Microscopic Understanding.

DTIC Science & Technology

1981-08-01

electro - optic effect is investigated both theoretically and experimentally. The theoretical approach is based upon W.A. Harrison’s ’Bond-Orbital Model’. The separate electronic and lattice contributions to the second-order, electro - optic susceptibility are examined within the context of this model and formulae which can accommodate any crystal structure are presented. In addition, a method for estimating the lattice response to a low frequency (dc) electric field is outlined. Finally, experimental measurements of the electro -

An analytical study of double bend achromat lattice.

PubMed

Fakhri, Ali Akbar; Kant, Pradeep; Singh, Gurnam; Ghodke, A D

2015-03-01

In a double bend achromat, Chasman-Green (CG) lattice represents the basic structure for low emittance synchrotron radiation sources. In the basic structure of CG lattice single focussing quadrupole (QF) magnet is used to form an achromat. In this paper, this CG lattice is discussed and an analytical relation is presented, showing the limitation of basic CG lattice to provide the theoretical minimum beam emittance in achromatic condition. To satisfy theoretical minimum beam emittance parameters, achromat having two, three, and four quadrupole structures is presented. In this structure, different arrangements of QF and defocusing quadruple (QD) are used. An analytical approach assuming quadrupoles as thin lenses has been followed for studying these structures. A study of Indus-2 lattice in which QF-QD-QF configuration in the achromat part has been adopted is also presented.

Theoretical study of corrugated plates: Shearing of a trapezoidally corrugated plate with trough lines permitted to curve

NASA Technical Reports Server (NTRS)

Lin, C.; Libove, C.

1971-01-01

A theoretical analysis is presented of the elastic shearing of a trapezoidally corrugated plate with discrete attachments at the ends of the corrugations. Numerical results on effective shear stiffness, stresses, and displacements are presented for selected geometries and end-attachment conditions. It is shown that the frame-like deformation of the cross-sections, which results from the absence of continuous end attachments, can lead to large transverse bending stresses and large reductions in shearing stiffness.

A theoretical investigation of single-molecule fluorescence detection on thin metallic layers.

PubMed

Enderlein, J

2000-04-01

In the present paper, the excitation and detection of single-molecule fluorescence over thin metallic films is studied theoretically within the framework of classical electrodynamics. The model takes into account the specific conditions of surface plasmon-assisted optical excitation, fluorescence quenching by the metal film, and detection geometry. Extensive numerical results are presented for gold, silver, and aluminum films, showing the detectable fluorescence intensities and their dependence on film thickness and the fluorescent molecule's position under optimal excitation conditions.

Analysis of multimode fiber bundles for endoscopic spectral-domain optical coherence tomography

PubMed Central

Risi, Matthew D.; Makhlouf, Houssine; Rouse, Andrew R.; Gmitro, Arthur F.

2016-01-01

A theoretical analysis of the use of a fiber bundle in spectral-domain optical coherence tomography (OCT) systems is presented. The fiber bundle enables a flexible endoscopic design and provides fast, parallelized acquisition of the OCT data. However, the multimode characteristic of the fibers in the fiber bundle affects the depth sensitivity of the imaging system. A description of light interference in a multimode fiber is presented along with numerical simulations and experimental studies to illustrate the theoretical analysis. PMID:25967012

The anharmonic quartic force field infrared spectra of five non-linear polycyclic aromatic hydrocarbons: Benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene

NASA Astrophysics Data System (ADS)

Mackie, Cameron J.; Candian, Alessandra; Huang, Xinchuan; Maltseva, Elena; Petrignani, Annemieke; Oomens, Jos; Mattioda, Andrew L.; Buma, Wybren Jan; Lee, Timothy J.; Tielens, Alexander G. G. M.

2016-08-01

The study of interstellar polycyclic aromatic hydrocarbons (PAHs) relies heavily on theoretically predicted infrared spectra. Most earlier studies use scaled harmonic frequencies for band positions and the double harmonic approximation for intensities. However, recent high-resolution gas-phase experimental spectroscopic studies have shown that the harmonic approximation is not sufficient to reproduce experimental results. In our previous work, we presented the anharmonic theoretical spectra of three linear PAHs, showing the importance of including anharmonicities into the theoretical calculations. In this paper, we continue this work by extending the study to include five non-linear PAHs (benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene), thereby allowing us to make a full assessment of how edge structure, symmetry, and size influence the effects of anharmonicities. The theoretical anharmonic spectra are compared to spectra obtained under matrix isolation low-temperature conditions, low-resolution, high-temperature gas-phase conditions, and high-resolution, low-temperature gas-phase conditions. Overall, excellent agreement is observed between the theoretical and experimental spectra although the experimental spectra show subtle but significant differences.

The anharmonic quartic force field infrared spectra of five non-linear polycyclic aromatic hydrocarbons: Benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene.

PubMed

Mackie, Cameron J; Candian, Alessandra; Huang, Xinchuan; Maltseva, Elena; Petrignani, Annemieke; Oomens, Jos; Mattioda, Andrew L; Buma, Wybren Jan; Lee, Timothy J; Tielens, Alexander G G M

2016-08-28

The study of interstellar polycyclic aromatic hydrocarbons (PAHs) relies heavily on theoretically predicted infrared spectra. Most earlier studies use scaled harmonic frequencies for band positions and the double harmonic approximation for intensities. However, recent high-resolution gas-phase experimental spectroscopic studies have shown that the harmonic approximation is not sufficient to reproduce experimental results. In our previous work, we presented the anharmonic theoretical spectra of three linear PAHs, showing the importance of including anharmonicities into the theoretical calculations. In this paper, we continue this work by extending the study to include five non-linear PAHs (benz[a]anthracene, chrysene, phenanthrene, pyrene, and triphenylene), thereby allowing us to make a full assessment of how edge structure, symmetry, and size influence the effects of anharmonicities. The theoretical anharmonic spectra are compared to spectra obtained under matrix isolation low-temperature conditions, low-resolution, high-temperature gas-phase conditions, and high-resolution, low-temperature gas-phase conditions. Overall, excellent agreement is observed between the theoretical and experimental spectra although the experimental spectra show subtle but significant differences.

Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

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

Barbosa, Alessandra Souza; Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica; Varella, Márcio T. do N.

2016-08-28

In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in themore » high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7{sup ∘} to 110{sup ∘}. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene.« less

Vector wind profile gust model

NASA Technical Reports Server (NTRS)

Adelfang, S. I.

1979-01-01

Work towards establishing a vector wind profile gust model for the Space Transportation System flight operations and trade studies is reported. To date, all the statistical and computational techniques required were established and partially implemented. An analysis of wind profile gust at Cape Kennedy within the theoretical framework is presented. The variability of theoretical and observed gust magnitude with filter type, altitude, and season is described. Various examples are presented which illustrate agreement between theoretical and observed gust percentiles. The preliminary analysis of the gust data indicates a strong variability with altitude, season, and wavelength regime. An extension of the analyses to include conditional distributions of gust magnitude given gust length, distributions of gust modulus, and phase differences between gust components has begun.

Experimental and theoretical study of magnetohydrodynamic ship models.

PubMed

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

2017-01-01

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

Experimental and theoretical study of magnetohydrodynamic ship models

PubMed Central

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

2017-01-01

Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques. PMID:28665941

Theoretical Study of the Effect of Enamel Parameters on Laser-Induced Surface Acoustic Waves in Human Incisor

NASA Astrophysics Data System (ADS)

Yuan, Ling; Sun, Kaihua; Shen, Zhonghua; Ni, Xiaowu; Lu, Jian

2015-06-01

The laser ultrasound technique has great potential for clinical diagnosis of teeth because of its many advantages. To study laser surface acoustic wave (LSAW) propagation in human teeth, two theoretical methods, the finite element method (FEM) and Laguerre polynomial extension method (LPEM), are presented. The full field temperature values and SAW displacements in an incisor can be obtained by the FEM. The SAW phase velocity in a healthy incisor and dental caries is obtained by the LPEM. The methods and results of this work can provide a theoretical basis for nondestructive evaluation of human teeth with LSAWs.

The Theoretical Research Article as a Reflection of Disciplinary Practices: The Case of Pure Mathematics

ERIC Educational Resources Information Center

Kuteeva, Maria; McGrath, Lisa

2015-01-01

Recent years have seen an interest in the generic structure of empirical research articles across a variety of disciplines. However, significantly less attention has been given to theoretical articles. This study aims to begin to address this imbalance by presenting the results of an investigation into the organizational and rhetorical structure…

Lee side flow for slender delta wings of finite thickness

NASA Technical Reports Server (NTRS)

Szodruch, J. G.

1980-01-01

An experimental and theoretical investigation carried out to determine the lee side flow field over delta wings at supersonic speeds is presented. A theoretical method to described the flow field is described, where boundary conditions as a result of the experimental study are needed. The computed flow field with shock induced separation is satisfactory.

Recent theoretical chemical dynamics at Rochester in the paths of Joseph O. Hirschfelder

NASA Technical Reports Server (NTRS)

George, T. F.; Lam, K.-S.; Bhattacharyya, D. K.; Hutchinson, M.; Zimmerman, I. H.; Devries, P. L.; Yuan, J.-M.

1982-01-01

A review of recent theoretical studies of gas-phase molecular rate processes, including various effects of laser radiation, is presented in the context of the extensive and influential work of Joseph O. Hirschfelder during the past half-century. The topics addressed are energy transfer, chemical reactions, unimolecular dissociation, transition states, and bound-continuum interactions.

Naïve Scientists and Conflict Analysis: Learning through Case Studies

ERIC Educational Resources Information Center

Ayres, R. Williams

2016-01-01

Much of our teaching about conflict relies on theoretical ideas and models that are delivered as finished products. This article explores the supposition that what students need is not already-formed theoretical ideas, but exposure to more real-world cases of conflict from which to build theory. The article presents an experiment in pedagogy:…

Experimental and theoretical study of the operation of longitudinal sidewalls in reinforced concrete superstructures

NASA Astrophysics Data System (ADS)

Bokarev, Sergey; Efimov, Stefan

2017-11-01

In the present article, we report results of a laboratory experimental study of reinforced-concrete superstructure fragments with extended longitudinal boxing sidewalls. The study included laboratory tests and numerical experiments performed using a finite element model of fragments generated in specialized simulation software. The distribution of horizontal pressures over the height of longitudinal boxing sidewalls, the dependence of the bending moment in the root section of the sidewalls on the ballast-bed thickness under sleepers, and some other characteristics were examined. The results of the experimental and theoretical study have shown a good convergence of obtained data to each other and to the data obtained by an improved engineering calculation procedure proposed by the present authors.

Experimental and theoretical studies of a pyrazole-thiazolidin-2,4-di-one hybrid

NASA Astrophysics Data System (ADS)

Mushtaque, Md.; Avecilla, Fernando; Haque, Ashanul; Perwez, Ahmad; Khan, Md. Shahzad; Rizvi, M. Moshahid Alam

2017-08-01

The present work describes synthesis, characterization and biological evaluations of a hybrid compound 10 composed of two intriguing scaffolds pyrazole and thiazolidin-2,4-di-one. The title compound was obtained via multi-step reaction and characterized by a number of techniques (viz. IR, UV-Visible, 1H-NMR, 13C-NMR and MS) including X-ray crystallography. The structural and photophysical data of compound 10 were well supported by theoretical calculations performed at density functional (DFT) level. In-vitro anticancer studies on different human cancer cell lines indicated moderate to low activity of the compounds. The molecular target of the compound was predicted through in-silico studies. Finding of the studies are presented herein.

High lying energy positions of doubly (2p ns) 1,3P° and (2p nd) 1,3P° excited states of the beryllium atom

NASA Astrophysics Data System (ADS)

Sakho, I.

2011-12-01

The Screening Constant by Unit Nuclear Charge (SCUNC) method is used to study (2p ns) 1,3P° and (2p nd) 1,3P° autoionizing states of the beryllium atom. Energy positions are reported up to n=20. In addition, resonance widths of the (2p ns) 1P° states also presented. The current results compared very well to available theoretical and experimental literature values up to n=15. The accurate data presented in this work may be of interest for future experimental and theoretical studies in the photoabsorption spectrum of Be.

Study of inelastic e-Cd and e-Zn collisions

NASA Astrophysics Data System (ADS)

Piwinski, Mariusz; Klosowski, Lukasz; Dziczek, Darek; Chwirot, Stanislaw

2016-09-01

Electron-photon coincidence experiments are well known for providing more detailed information about electron-atom collision than any other technique. The Electron Impact Coherence Parameters (EICP) values obtained in such studies deliver the most complete characterization of the inelastic collision and allow for a verification of proposed theoretical models. We present the results of Stokes and EICP parameters characterising electronic excitation of the lowest singlet P-state of cadmium and zinc atoms for various collision energies. The experiments were performed using electron-photon coincidence technique in the coherence analysis version. The obtained data are presented and compared with existing CCC and RDWA theoretical predictions.

Recent development in lattice QCD studies for three-nucleon forces

NASA Astrophysics Data System (ADS)

Doi, Takumi; HAL QCD Collaboration

2014-09-01

The direct determination of nuclear forces from QCD has been one of the most desirable challenges in nuclear physics. Recently, a first-principles lattice QCD determination is becoming possible by a novel theoretical method, HAL QCD method, in which Nambu-Bethe-Salpeter (NBS) wave functions are utilized. In this talk, I will focus on the study of three-nucleon forces in HAL QCD method by presenting the recent theoretical/numerical development.

Theoretical methods for estimating moments of inertia of trees and boles.

Treesearch

John A. Sturos

1973-01-01

Presents a theoretical method for estimating the mass moments of inertia of full trees and boles about a transverse axis. Estimates from the theoretical model compared closely with experimental data on aspen and red pine trees obtained in the field by the pendulum method. The theoretical method presented may be used to estimate the mass moments of inertia and other...

Perspectives on hypersonic viscous flow research

NASA Technical Reports Server (NTRS)

Cheng, H. K.

1993-01-01

Issues and advances in current hypersonic flow research perceived to be of interest in theoretical fluid/gas dynamics are reviewed. Particular attention is given to the hypersonic aircraft as waverider, computational methods and theoretical development in the study of viscous interaction, and boundary-layer instability and transition studies. In the present framework the study of viscous hypersonic flow faces transition problems of two kinds which represent the two major areas of current research: the turbulence transition in the high Re range and the transition to the free-molecule limit.

The stratosphere: Present and future

NASA Technical Reports Server (NTRS)

Hudson, R. D. (Editor); Reed, E. I. (Editor)

1979-01-01

The present status of stratospheric science is discussed. The three basic elements of stratospheric science-laboratory measurements, atmospheric observations, and theoretical studies are presented along with an attempt to predict, with reasonable confidence, the effect on ozone of particular anthropogenic sources of pollution.

Pressure variation of developed lapping tool on surface roughness

NASA Astrophysics Data System (ADS)

Hussain, A. K.; Lee, K. Q.; Aung, L. M.; Abu, A.; Tan, L. K.; Kang, H. S.

2018-01-01

Improving the surface roughness is always one of the major concerns in the development of lapping process as high precision machining caters a great demand in manufacturing process. This paper aims to investigate the performance of a newly designed lapping tool in term of surface roughness. Polypropylene is used as the lapping tool head. The lapping tool is tested for different pressure to identify the optimum working pressure for lapping process. The theoretical surface roughness is also calculated using Vickers Hardness. The present study shows that polypropylene is able to produce good quality and smooth surface roughness. The optimum lapping pressure in the present study is found to be 45 MPa. By comparing the theoretical and experimental values, the present study shows that the newly designed lapping tool is capable to produce finer surface roughness.

Heavy use of equations impedes communication among biologists.

PubMed

Fawcett, Tim W; Higginson, Andrew D

2012-07-17

Most research in biology is empirical, yet empirical studies rely fundamentally on theoretical work for generating testable predictions and interpreting observations. Despite this interdependence, many empirical studies build largely on other empirical studies with little direct reference to relevant theory, suggesting a failure of communication that may hinder scientific progress. To investigate the extent of this problem, we analyzed how the use of mathematical equations affects the scientific impact of studies in ecology and evolution. The density of equations in an article has a significant negative impact on citation rates, with papers receiving 28% fewer citations overall for each additional equation per page in the main text. Long, equation-dense papers tend to be more frequently cited by other theoretical papers, but this increase is outweighed by a sharp drop in citations from nontheoretical papers (35% fewer citations for each additional equation per page in the main text). In contrast, equations presented in an accompanying appendix do not lessen a paper's impact. Our analysis suggests possible strategies for enhancing the presentation of mathematical models to facilitate progress in disciplines that rely on the tight integration of theoretical and empirical work.

Integrated primary care, the collaboration imperative inter-organizational cooperation in the integrated primary care field: a theoretical framework

PubMed Central

Valentijn, Pim P; Bruijnzeels, Marc A; de Leeuw, Rob J; Schrijvers, Guus J.P

2012-01-01

Purpose Capacity problems and political pressures have led to a rapid change in the organization of primary care from mono disciplinary small business to complex inter-organizational relationships. It is assumed that inter-organizational collaboration is the driving force to achieve integrated (primary) care. Despite the importance of collaboration and integration of services in primary care, there is no unambiguous definition for both concepts. The purpose of this study is to examine and link the conceptualisation and validation of the terms inter-organizational collaboration and integrated primary care using a theoretical framework. Theory The theoretical framework is based on the complex collaboration process of negotiation among multiple stakeholder groups in primary care. Methods A literature review of health sciences and business databases, and targeted grey literature sources. Based on the literature review we operationalized the constructs of inter-organizational collaboration and integrated primary care in a theoretical framework. The framework is being validated in an explorative study of 80 primary care projects in the Netherlands. Results and conclusions Integrated primary care is considered as a multidimensional construct based on a continuum of integration, extending from segregation to integration. The synthesis of the current theories and concepts of inter-organizational collaboration is insufficient to deal with the complexity of collaborative issues in primary care. One coherent and integrated theoretical framework was found that could make the complex collaboration process in primary care transparent. This study presented theoretical framework is a first step to understand the patterns of successful collaboration and integration in primary care services. These patterns can give insights in the organization forms needed to create a good working integrated (primary) care system that fits the local needs of a population. Preliminary data of the patterns of collaboration and integration will be presented.

Circumstellar chemistry

NASA Technical Reports Server (NTRS)

Glassgold, Alfred E.; Huggins, Patrick J.

1987-01-01

The study of the outer envelopes of cool evolved stars has become an active area of research. The physical properties of CS envelopes are presented. Observations of many wavelengths bands are relevant. A summary of observations and a discussion of theoretical considerations concerning the chemistry are summarized. Recent theoretical considerations show that the thermal equilibrium model is of limited use for understanding the chemistry of the outer CS envelopes. The theoretical modeling of the chemistry of CS envelopes provides a quantitive test of chemical concepts which have a broader interest than the envelopes themselves.

Transonic Flow Past Cone Cylinders

NASA Technical Reports Server (NTRS)

Solomon, George E

1955-01-01

Experimental results are presented for transonic flow post cone-cylinder, axially symmetric bodies. The drag coefficient and surface Mach number are studied as the free-stream Mach number is varied and, wherever possible, the experimental results are compared with theoretical predictions. Interferometric results for several typical flow configurations are shown and an example of shock-free supersonic-to-subsonic compression is experimentally demonstrated. The theoretical problem of transonic flow past finite cones is discussed briefly and an approximate solution of the axially symmetric transonic equations, valid for a semi-infinite cone, is presented.

Pressure induced phase transition and elastic properties of cerium mono-nitride (CeN)

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

Yaduvanshi, Namrata, E-mail: namrata-yaduvanshi@yahoo.com; Singh, Sadhna

2016-05-23

In the present paper, we have investigated the high-pressure structural phase transition and elastic properties of cerium mono-nitride. We studied theoretically the structural properties of this compound (CeN) by using the improved interaction potential model (IIPM) approach. This compound exhibits first order crystallographic phase transition from NaCl (B{sub 1}) to tetragonal (BCT) phase at 37 GPa. The phase transition pressures and associated volume collapse obtained from present potential model (IIPM) show a good agreement with available theoretical data.

Theoretical analysis on the measurement errors of local 2D DIC: Part I temporal and spatial uncertainty quantification of displacement measurements

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

Wang, Yueqi; Lava, Pascal; Reu, Phillip

This study presents a theoretical uncertainty quantification of displacement measurements by subset-based 2D-digital image correlation. A generalized solution to estimate the random error of displacement measurement is presented. The obtained solution suggests that the random error of displacement measurements is determined by the image noise, the summation of the intensity gradient in a subset, the subpixel part of displacement, and the interpolation scheme. The proposed method is validated with virtual digital image correlation tests.

Theoretical analysis on the measurement errors of local 2D DIC: Part I temporal and spatial uncertainty quantification of displacement measurements

DOE PAGES

Wang, Yueqi; Lava, Pascal; Reu, Phillip; ...

2015-12-23

This study presents a theoretical uncertainty quantification of displacement measurements by subset-based 2D-digital image correlation. A generalized solution to estimate the random error of displacement measurement is presented. The obtained solution suggests that the random error of displacement measurements is determined by the image noise, the summation of the intensity gradient in a subset, the subpixel part of displacement, and the interpolation scheme. The proposed method is validated with virtual digital image correlation tests.

Results and conclusions: perception sensor study for high speed autonomous operations

NASA Astrophysics Data System (ADS)

Schneider, Anne; LaCelle, Zachary; Lacaze, Alberto; Murphy, Karl; Close, Ryan

2016-05-01

Previous research has presented work on sensor requirements, specifications, and testing, to evaluate the feasibility of increasing autonomous vehicle system speeds. Discussions included the theoretical background for determining sensor requirements, and the basic test setup and evaluation criteria for comparing existing and prototype sensor designs. This paper will present and discuss the continuation of this work. In particular, this paper will focus on analyzing the problem via a real-world comparison of various sensor technology testing results, as opposed to previous work that utilized more of a theoretical approach. LADAR/LIDAR, radar, visual, and infrared sensors are considered in this research. Results are evaluated against the theoretical, desired perception specifications. Conclusions for utilizing a suite of perception sensors, to achieve the goal of doubling ground vehicle speeds, is also discussed.

Analysis of the Underlying Cognitive Activity in the Resolution of a Task on Derivability of the Absolute-Value Function: Two Theoretical Perspectives

ERIC Educational Resources Information Center

Pino-Fan, Luis R.; Guzmán, Ismenia; Font, Vicenç; Duval, Raymond

2017-01-01

This paper presents a study of networking of theories between the theory of registers of semiotic representation (TRSR) and the onto-semiotic approach of mathematical cognition and instruction (OSA). The results obtained show complementarities between these two theoretical perspectives, which might allow more detailed analysis of the students'…

Using Bogner and Wiseman's Model of Ecological Values to Measure the Impact of an Earth Education Programme on Children's Environmental Perceptions

ERIC Educational Resources Information Center

Johnson, Bruce; Manoli, Constantinos C.

2008-01-01

Investigating the effects of educational programmes on children's environmental perceptions has been hampered by the lack of good theoretical models and valid instruments. In the present study, Bogner and Wiseman's Model of Ecological Values provided a well-developed theoretical model. A validated instrument based on Bogner's Environmental…

Elastic solitons in delaminated bars: splitting leads to fission

NASA Astrophysics Data System (ADS)

Samsonov, A. M.; Dreiden, G. V.; Khusnutdinova, K. R.; Semenova, I. V.

2008-06-01

Recent theoretical and successful experimental studies confirmed existence and demonstrated main properties of bulk strain solitary waves in nonlinearly elastic solid wave guides. Our current research is devoted to nonlinear wave processes in layered elastic wave guides with inhomogeneities modelling delamination. We present first theoretical and experimental results showing the influence of delamination on the parameters of the longitudinal strain solitary wave.

Developing EFL Learners' Speaking Skills through Dynamic Assessment: A Case of A Beginner and an Advanced Learner

ERIC Educational Resources Information Center

Ebadi, Saman; Asakereh, Ahmad

2017-01-01

Dynamic assessment (DA), having its theoretical base in Vygotskyan Sociocultural theory of mind, is a newly developed classroom assessment through which learners are helped to perform beyond their current ability. Drawing upon the theoretical aspect of DA, the present study explored the impact of DA on the development of speaking skills. To this…

Music Therapy for Posttraumatic Stress in Adults: A Theoretical Review

PubMed Central

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

2017-01-01

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

Talbot self-imaging phenomenon under Bessel beam illumination

NASA Astrophysics Data System (ADS)

Chakraborty, Rijuparna; Chowdhury, Subhajit Dutta; Chakraborty, Ajoy Kumar

2018-06-01

In this paper, we report the results of our theoretical studies on the phenomenon of self-imaging of periodic object under the illumination of zero-order Bessel beam. Our theoretical analysis indicates that the self-images are visible only after the walk-off distance of the Bessel beam used. It is also observed that the self-images bend around the optical axis of the setup. Besides, the present study justifies the importance of the conditions stipulated by Montgomery.

MHD-waves in the geomagnetic tail: A review

NASA Astrophysics Data System (ADS)

Leonovich, Anatoliy; Mazur, Vitaliy; Kozlov, Daniil

2015-03-01

This article presents the review of experimental and theoretical studies on ultra-lowfrequency MHD oscillations of the geomagnetic tail. We consider the Kelvin-Helmholtz instability at the magnetopause, oscillations with a discrete spectrum in the "magic frequencies"range, the ballooning instability of coupled Alfvén and slow magnetosonic waves, and "flapping" oscillations of the current sheet of the geomagnetic tail. Over the last decade, observations from THEMIS, CLUSTER and Double Star satellites have been of great importance for experimental studies. The use of several spacecraft allows us to study the structure of MHD oscillations with high spatial resolution. Due to this, we can make a detailed comparison between theoretical results and those obtained from multi-spacecraft studies. To make such comparisons in theoretical studies, in turn, we have to use the numerical models closest to the real magnetosphere.

[Efficacy analysis and theoretical study on Chinese herbal properties of Açaí (Euterpe oleracea)].

PubMed

Zhang, Jian-jun; Chen, Shao-hong; Zhu, Ying-li; Wang, Chun; Wang, Jing-xia; Wang, Lin-yuan; Gao, Xue-min

2015-06-01

Açaí (Euterpe oleracea) emerged as a source of herb has a long history in South America, which was approved by the Ministry of Health used in China and it has been introduced planting in Guangdong and Taiwan. This article summarized applied history of Açaí and its present status in China. Did theoretical study on the Chinese herbal properties of Açaí based on the Chinese traditional philosophical culture to analysis the function and symptom preliminary, combining with used for medical recordation, chemical component, biological activity. It is aiming at establishing the theoretical foundation for the application under the guidance of TCM theory.

Theoretical Grounding: The "Missing Link" in Suicide Research.

ERIC Educational Resources Information Center

Rogers, James R.

2001-01-01

Discusses the strengths and limitations of the current pragmatic focus of research in suicidology and presents an argument for theoretical grounding as a precursor for continued advancement in this area. Presents an existential-constructivist framework of "meaning creation" as a theoretical heuristic for understanding suicide. Outlines general…

Student-Initiated Use of Facebook for Learning Online Journalism

ERIC Educational Resources Information Center

Song, Yang

2017-01-01

This article presents a case study of student-initiated use of Facebook Groups in doing a team project for an online journalism course. Drawing upon the concept of affinity space and a theoretical taxonomy of asynchronous online discussion, the present study triangulates classroom observation, semi-structured student interviews, and microanalysis…

Play-Based Art Activities in Early Years: Teachers' Thinking and Practice

ERIC Educational Resources Information Center

Savva, Andri; Erakleous, Valentina

2018-01-01

The present study reports findings on pre-service teachers' thinking during planning and implementing play-based art activities. "Thinking" (in the present study) is informed by discourses emphasising art teaching and learning in relation to play and theoretical assumptions conceptualising planning as "practice of knowing."…

Professional Development and Use of Digital Technologies by Science Teachers: a Review of Theoretical Frameworks

NASA Astrophysics Data System (ADS)

Fernandes, Geraldo W. Rocha; Rodrigues, António M.; Ferreira, Carlos Alberto

2018-03-01

This article aims to characterise the research on science teachers' professional development programs that support the use of Information and Communication Technologies (ICTs) and the main trends concerning the theoretical frameworks (theoretical foundation, literature review or background) that underpin these studies. Through a systematic review of the literature, 76 articles were found and divided into two axes on training science teachers and the use of digital technologies with their categories. The first axis (characterisation of articles) presents the category key features that characterise the articles selected (major subjects, training and actions for the professional development and major ICT tools and digital resources). The second axis (trends of theoretical frameworks) has three categories organised in theoretical frameworks that emphasise the following: (a) the digital technologies, (b) prospects of curricular renewal and (c) cognitive processes. It also characterised a group of articles with theoretical frameworks that contain multiple elements without deepening them or that even lack a theoretical framework that supports the studies. In this review, we found that many professional development programs for teachers still use inadequate strategies for bringing about change in teacher practices. New professional development proposals are emerging with the objective of minimising such difficulties and this analysis could be a helpful tool to restructure those proposals.

Border and surface tracing--theoretical foundations.

PubMed

Brimkov, Valentin E; Klette, Reinhard

2008-04-01

In this paper we define and study digital manifolds of arbitrary dimension, and provide (in particular)a general theoretical basis for curve or surface tracing in picture analysis. The studies involve properties such as one-dimensionality of digital curves and (n-1)-dimensionality of digital hypersurfaces that makes them discrete analogs of corresponding notions in continuous topology. The presented approach is fully based on the concept of adjacency relation and complements the concept of dimension as common in combinatorial topology. This work appears to be the first one on digital manifolds based ona graph-theoretical definition of dimension. In particular, in the n-dimensional digital space, a digital curve is a one-dimensional object and a digital hypersurface is an (n-1)-dimensional object, as it is in the case of curves and hypersurfaces in the Euclidean space. Relying on the obtained properties of digital hypersurfaces, we propose a uniform approach for studying good pairs defined by separations and obtain a classification of good pairs in arbitrary dimension. We also discuss possible applications of the presented definitions and results.

Reactive sites influence in PMMA oligomers reactivity: a DFT study

NASA Astrophysics Data System (ADS)

Paz, C. V.; Vásquez, S. R.; Flores, N.; García, L.; Rico, J. L.

2018-01-01

In this work, we present a theoretical study of methyl methacrylate (MMA) living anionic polymerization. The study was addressed to understanding two important experimental observations made for Michael Szwarc in 1956. The unexpected effect of reactive sites concentration in the propagation rate, and the self-killer behavior of MMA (deactivating of living anionic polymerization). The theoretical calculations were performed by density functional theory (DFT) to obtain the frontier molecular orbitals values. These values were used to calculate and analyze the chemical interaction descriptors in DFT-Koopmans’ theorem. As a result, it was observed that the longest chain-length species (related with low concentration of reactive sites) exhibit the highest reactivity (behavior associated with the increase of the propagation rate). The improvement in this reactivity was attributed to the crosslinking produced in the polymethyl methacrylate chains. Meanwhile, the self-killer behavior was associated with the intermolecular forces present in the reactive sites. This behavior was associated to an obstruction in solvation, since the active sites remained active through all propagation species. The theoretical results were in good agreement with the Szwarc experiments.

Theoretical study of the magnetic behavior of hexanuclear Cu(II) and Ni(II) polysiloxanolato complexes.

PubMed

Ruiz, Eliseo; Cano, Joan; Alvarez, Santiago; Caneschi, Andrea; Gatteschi, Dante

2003-06-04

A theoretical density functional study of the exchange coupling in hexanuclear polysiloxanolato-bridged complexes of Cu(II) and Ni(II) is presented. By calculating the energies of three different spin configurations, we can obtain estimates of the first-, second-, and third-neighbor exchange coupling constants. The study has been carried out for the complete structures of the Cu pristine cluster and of the chloroenclathrated Ni complex as well as for the hypotethical pristine Ni compound and for magnetically dinuclear analogues M(2)Zn(4) (M = Cu, Ni).

The Situation of ICT Usage in Nagoya University Law School

NASA Astrophysics Data System (ADS)

Kaneko, Daisuke; Sugawara, Ikuo

Since the introduction of a new legal education system in 2004, some of Japanese legal educational institutions have changed into professional schools which names are Law School. These law schools are required not only theoretical studies but also professional skills training. Law students, however, have limited time to complete this agenda, so law professors have to teach courses effectively. In this paper, the authors present the situation of ICT usage in Nagoya University Law School as a case study to describe and to critique systems to support theoretical studies and professional skills training.

An Analysis of Machine- and Human-Analytics in Classification.

PubMed

Tam, Gary K L; Kothari, Vivek; Chen, Min

2017-01-01

In this work, we present a study that traces the technical and cognitive processes in two visual analytics applications to a common theoretic model of soft knowledge that may be added into a visual analytics process for constructing a decision-tree model. Both case studies involved the development of classification models based on the "bag of features" approach. Both compared a visual analytics approach using parallel coordinates with a machine-learning approach using information theory. Both found that the visual analytics approach had some advantages over the machine learning approach, especially when sparse datasets were used as the ground truth. We examine various possible factors that may have contributed to such advantages, and collect empirical evidence for supporting the observation and reasoning of these factors. We propose an information-theoretic model as a common theoretic basis to explain the phenomena exhibited in these two case studies. Together we provide interconnected empirical and theoretical evidence to support the usefulness of visual analytics.

Recent research related to prediction of stall/spin characteristics of fighter aircraft

NASA Technical Reports Server (NTRS)

Nguyen, L. T.; Anglin, E. L.; Gilbert, W. P.

1976-01-01

The NASA Langley Research Center is currently engaged in a stall/spin research program to provide the fundamental information and design guidelines required to predict the stall/spin characteristics of fighter aircraft. The prediction methods under study include theoretical spin prediction techniques and piloted simulation studies. The paper discusses the overall status of theoretical techniques including: (1) input data requirements, (2) math model requirements, and (3) correlation between theoretical and experimental results. The Langley Differential Maneuvering Simulator (DMS) facility has been used to evaluate the spin susceptibility of several current fighters during typical air combat maneuvers and to develop and evaluate the effectiveness of automatic departure/spin prevention concepts. The evaluation procedure is described and some of the more significant results of the studies are presented.

Study into penetration speed during laser cutting of brain tissues.

PubMed

Yilbas, Z; Sami, M; Patiroglu, T

1998-01-01

The applications of CO2 continuous-wave lasers in neurosurgery have become important in recent years. Theoretical considerations of laser applicability in medicine are subsequently confirmed experimentally. To obtain precision operation in the laser cutting process, further theoretical developments and experimental studies need to be conducted. Consequently, in the present study, the heat transfer mechanism taking place during laser-tissue interaction is introduced using Fourier theory. The results obtained from the theoretical model are compared with the experimental results. In connection with this, an experiment is designed to measure the penetration speed during the laser cutting process. The measurement is carried out using an optical method. It is found that both results for the penetration speed obtained from the theory and experiment are in a good agreement.

An Experimental and Theoretical Study on Cavitating Propellers.

DTIC Science & Technology

1982-10-01

34 And Identfyp eV &to" nMeeJ cascade flow theoretical supercavitating flow performance prediction method partially cavitating flow supercavitating ...the present work was to develop an analytical tool for predicting the off-design performance of supercavitating propellers over a wide range of...operating conditions. Due to the complex nature of the flow phenomena, a lifting line theory sirply combined with the two-dimensional supercavitating

E-assessment of prior learning: a pilot study of interactive assessment of staff with no formal education who are working in Swedish elderly care

PubMed Central

2014-01-01

Background The current paper presents a pilot study of interactive assessment using information and communication technology (ICT) to evaluate the knowledge, skills and abilities of staff with no formal education who are working in Swedish elderly care. Methods Theoretical and practical assessment methods were developed and used with simulated patients and computer-based tests to identify strengths and areas for personal development among staff with no formal education. Results Of the 157 staff with no formal education, 87 began the practical and/or theoretical assessments, and 63 completed both assessments. Several of the staff passed the practical assessments, except the morning hygiene assessment, where several failed. Other areas for staff development, i.e. where several failed (>50%), were the theoretical assessment of the learning objectives: Health, Oral care, Ergonomics, hygiene, esthetic, environmental, Rehabilitation, Assistive technology, Basic healthcare and Laws and organization. None of the staff passed all assessments. Number of years working in elderly care and staff age were not statistically significantly related to the total score of grades on the various learning objectives. Conclusion The interactive assessments were useful in assessing staff members’ practical and theoretical knowledge, skills, and abilities and in identifying areas in need of development. It is important that personnel who lack formal qualifications be clearly identified and given a chance to develop their competence through training, both theoretical and practical. The interactive e-assessment approach analyzed in the present pilot study could serve as a starting point. PMID:24742168

Crystal study and econometric model

NASA Technical Reports Server (NTRS)

1975-01-01

An econometric model was developed that can be used to predict demand and supply figures for crystals over a time horizon roughly concurrent with that of NASA's Space Shuttle Program - that is, 1975 through 1990. The model includes an equation to predict the impact on investment in the crystal-growing industry. Actually, two models are presented. The first is a theoretical model which follows rather strictly the standard theoretical economic concepts involved in supply and demand analysis, and a modified version of the model was developed which, though not quite as theoretically sound, was testable utilizing existing data sources.

Empathy and child neglect: a theoretical model.

PubMed

De Paul, Joaquín; Guibert, María

2008-11-01

To present an explanatory theory-based model of child neglect. This model does not address neglectful behaviors of parents with mental retardation, alcohol or drug abuse, or severe mental health problems. In this model parental behavior aimed to satisfy a child's need is considered a helping behavior and, as a consequence, child neglect is considered as a specific type of non-helping behavior. The central hypothesis of the theoretical model presented here suggests that neglectful parents cannot develop the helping response set to care for their children because the observation of a child's signal of need does not lead to the experience of emotions that motivate helping or because the parents experience these emotions, but specific cognitions modify the motivation to help. The present theoretical model suggests that different typologies of neglectful parents could be developed based on different reasons that parents might not to experience emotions that motivate helping behaviors. The model can be helpful to promote new empirical studies about the etiology of different groups of neglectful families.

A monopole model for annihilation line emission from the Galactic center

NASA Astrophysics Data System (ADS)

Wang, D. Y.; Peng, Q. H.

Two traditional theoretical interpretations of the observed plasmapause are compared, namely, the plasmapause as: (1) the boundary between closed flux tubes that have been in the inner magnetosphere for several days and those that have recently drifted in from the magnetotail or (2) the last closed electric equipotential. Although the two interpretations become equivalent in the case where the electric-field pattern is steady for several days, interpretation 1 seems theoretically more secure for typical magnetospheric conditions. The results of old theoretical studies of the effects of time variations in the electric-field pattern on the shape of the plasmapause are reviewed briefly. The formulation of the present version of the Rice Convection Model is also reviewed. Preliminary results of recent computations of quiet-time electric fields, carried out with this model, are presented and discussed.

Human factors in operations design

NASA Technical Reports Server (NTRS)

Chafin, R. L.

1982-01-01

The manner in which organizations develop their organizational structure is considered, taking into account an example in which the environment changes for an older organization. In such cases, it would be preferable to have some theoretical foundation on which to base the restructuring of the organization to meet new environmental needs. A description is given of a theoretic foundation based on the principles of Differentiation/Integration and Procedural/Knowledge based operations. The organizational design principle of Differentiation and Integration has been presented by Lawrence and Lorsch (1969). The differentiation/integration processes are related to the organizational structures presented in studies concerning NASA Deep Space Network (DSN) operations. The principles presented provide valuable tools for analyzing operations organization.

Cosmic x ray physics

NASA Technical Reports Server (NTRS)

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1990-01-01

The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

A theoretical and empirical review of the death-thought accessibility concept in terror management research.

PubMed

Hayes, Joseph; Schimel, Jeff; Arndt, Jamie; Faucher, Erik H

2010-09-01

Terror management theory (TMT) highlights the motivational impact of thoughts of death in various aspects of everyday life. Since its inception in 1986, research on TMT has undergone a slight but significant shift from an almost exclusive focus on the manipulation of thoughts of death to a marked increase in studies that measure the accessibility of death-related cognition. Indeed, the number of death-thought accessibility (DTA) studies in the published literature has grown substantially in recent years. In light of this increasing reliance on the DTA concept, the present article is meant to provide a comprehensive theoretical and empirical review of the literature employing this concept. After discussing the roots of DTA, the authors outline the theoretical refinements to TMT that have accompanied significant research findings associated with the DTA concept. Four distinct categories (mortality salience, death association, anxiety-buffer threat, and dispositional) are derived to organize the reviewed DTA studies, and the theoretical implications of each category are discussed. Finally, a number of lingering empirical and theoretical issues in the DTA literature are discussed with the aim of stimulating and focusing future research on DTA specifically and TMT in general.

[Theoretical and methodological uses of research in Social and Human Sciences in Health].

PubMed

Deslandes, Suely Ferreira; Iriart, Jorge Alberto Bernstein

2012-12-01

The current article aims to map and critically reflect on the current theoretical and methodological uses of research in the subfield of social and human sciences in health. A convenience sample was used to select three Brazilian public health journals. Based on a reading of 1,128 abstracts published from 2009 to 2010, 266 articles were selected that presented the empirical base of research stemming from social and human sciences in health. The sample was classified thematically as "theoretical/ methodological reference", "study type/ methodological design", "analytical categories", "data production techniques", and "analytical procedures". We analyze the sample's emic categories, drawing on the authors' literal statements. All the classifications and respective variables were tabulated in Excel. Most of the articles were self-described as qualitative and used more than one data production technique. There was a wide variety of theoretical references, in contrast with the almost total predominance of a single type of data analysis (content analysis). In several cases, important gaps were identified in expounding the study methodology and instrumental use of the qualitative research techniques and methods. However, the review did highlight some new objects of study and innovations in theoretical and methodological approaches.

Nonlocal approach to the analysis of the stress distribution in granular systems. I. Theoretical framework

NASA Astrophysics Data System (ADS)

Kenkre, V. M.; Scott, J. E.; Pease, E. A.; Hurd, A. J.

1998-05-01

A theoretical framework for the analysis of the stress distribution in granular materials is presented. It makes use of a transformation of the vertical spatial coordinate into a formal time variable and the subsequent study of a generally non-Markoffian, i.e., memory-possessing (nonlocal) propagation equation. Previous treatments are obtained as particular cases corresponding to, respectively, wavelike and diffusive limits of the general evolution. Calculations are presented for stress propagation in bounded and unbounded media. They can be used to obtain desired features such as a prescribed stress distribution within the compact.

Adsorption of halogens on metal surfaces

NASA Astrophysics Data System (ADS)

Andryushechkin, B. V.; Pavlova, T. V.; Eltsov, K. N.

2018-06-01

This paper presents a review of the experimental and theoretical investigations of halogen interaction with metal surfaces. The emphasis was placed on the recent measurements performed with a scanning tunneling microscope in combination with density functional theory calculations. The surface structures formed on metal surface after halogen interaction are classified into three groups: chemisorbed monolayer, surface halide, bulk-like halide. Formation of monolayer structures is described in terms of surface phase transitions. Surface halide phases are considered to be intermediates between chemisorbed halogen and bulk halide. The modern theoretical approaches in studying the dynamics of metal halogenation reactions are also presented.

Implementation of an experimental program to investigate the performance characteristics of OMEGA navigation

NASA Technical Reports Server (NTRS)

Baxa, E. G., Jr.

1974-01-01

A theoretical formulation of differential and composite OMEGA error is presented to establish hypotheses about the functional relationships between various parameters and OMEGA navigational errors. Computer software developed to provide for extensive statistical analysis of the phase data is described. Results from the regression analysis used to conduct parameter sensitivity studies on differential OMEGA error tend to validate the theoretically based hypothesis concerning the relationship between uncorrected differential OMEGA error and receiver separation range and azimuth. Limited results of measurement of receiver repeatability error and line of position measurement error are also presented.

Five Secondary Teachers: Creating and Presenting a Teaching Persona

ERIC Educational Resources Information Center

Davis, Janine Schank

2011-01-01

This qualitative study investigates the ways that five secondary teachers developed and presented personae. The researcher collected and analyzed data using a theoretical frame based in social psychology, including Goffman's Presentation of Self in Everyday Life (1959), and Miles and Huberman's (1994) three-step approach to qualitative data…

Innovation value chain capability in Malaysian-owned company: A theoretical framework

NASA Astrophysics Data System (ADS)

Abidin, Norkisme Zainal; Suradi, Nur Riza Mohd

2014-09-01

Good quality products or services are no longer adequate to guarantee the sustainability of a company in the present competitive business. Prior research has developed various innovation models with the hope to better understand the innovativeness of the company. Due to countless definitions, indicators, factors, parameter and approaches in the study of innovation, it is difficult to ensure which one will best suit the Malaysian-owned company innovativeness. This paper aims to provide a theoretical background to support the framework of the innovation value chain capability in Malaysian-owned Company. The theoretical framework was based on the literature reviews, expert interviews and focus group study. The framework will be used to predict and assess the innovation value chain capability in Malaysian-owned company.

Energetic Neutral Atom Emissions From Venus: VEX Observations and Theoretical Modeling

NASA Technical Reports Server (NTRS)

Fok, M.-C.; Galli, A.; Tanaka, T.; Moore, T. E.; Wurz, P.; Holmstrom, M.

2007-01-01

Venus has almost no intrinsic magnetic field to shield itself from its surrounding environment. The solar wind thus directly interacts with the planetary ionosphere and atmosphere. One of the by-products of this close encounter is the production of energetic neutral atom (ENA) emissions. Theoretical studies have shown that significant amount of ENAs are emanated from the planet. The launch of the Venus Express (VEX) in 2005 provided the first light ever of the Venus ENA emissions. The observed ENA flux level and structure are in pretty good agreement with the theoretical studies. In this paper, we present VEX ENA data and the comparison with numerical simulations. We seek to understand the solar wind interaction with the planet and the impacts on its atmospheres.

Nuclear quadrupole resonance studies in semi-metallic structures

NASA Technical Reports Server (NTRS)

Murty, A. N.

1974-01-01

Both experimental and theoretical studies are presented on spectrum analysis of nuclear quadrupole resonance of antimony and arsenic tellurides. Numerical solutions for secular equations of the quadrupole interaction energy are also discussed.

Cosmic x ray physics

NASA Technical Reports Server (NTRS)

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1991-01-01

The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

Photonics and spectroscopy in nanojunctions: a theoretical insight

DOE PAGES

Galperin, Michael

2017-04-11

The progress of experimental techniques at the nanoscale in the last decade made optical measurements in current-carrying nanojunctions a reality, thus indicating the emergence of a new field of research coined optoelectronics. Optical spectroscopy of open nonequilibrium systems is a natural meeting point for (at least) two research areas: nonlinear optical spectroscopy and quantum transport, each with its own theoretical toolbox. We review recent progress in the field comparing theoretical treatments of optical response in nanojunctions as is accepted in nonlinear spectroscopy and quantum transport communities. A unified theoretical description of spectroscopy in nanojunctions is presented. Here, we argue thatmore » theoretical approaches of the quantum transport community (and in particular, the Green function based considerations) yield a convenient tool for optoelectronics when the radiation field is treated classically, and that differences between the toolboxes may become critical when studying the quantum radiation field in junctions.« less

Vibrational, structural and electronic properties investigation by DFT calculations and molecular docking studies with DNA topoisomerase II of strychnobrasiline type alkaloids: A theoretical approach for potentially bioactive molecules

NASA Astrophysics Data System (ADS)

Costa, Renyer A.; Oliveira, Kelson M. T.; Costa, Emmanoel Vilaça; Pinheiro, Maria L. B.

2017-10-01

A combined experimental and theoretical DFT study of the structural, vibrational and electronic properties of strychnobrasiline and 12-hydroxy-10,11-dimethoxystrychnobrasiline is presented using the Becke three-parameter Lee-Yang-Parr function (B3LYP) and 6-311G(2d,p) basis set. The theoretical geometry optimization data were compared with the X-ray data for a similar structure in the associated literature, showing close values. The calculated HOMO-LUMO gap values showed that the presence of substituents in the benzene ring influences the quantum properties which are directly related to the reactive properties. Theoretical UV spectra agreed well with the measured experimental data, with bands assigned. In addition, Natural Bond Orbitals (NBOs), Mapped molecular electrostatic potential surface (MEPS) and NLO calculations were also performed at the same theory level. The theoretical vibrational analysis revealed several characteristic vibrations that may be used as a diagnostic tool for other strychnobrasiline type alkaloids, simplifying their identification and structural characterization. Molecular docking calculations with DNA Topoisomerase II-DNA complex showed binding free energies values of -8.0 and -9.5 kcal/mol for strychnobrasiline and 12-hydroxy-10,11-dimethoxystrychnobrasiline respectively, while for amsacrine, used for the treatment of leukemia, the binding free energy ΔG presented a value of -10.0 kcal/mol, suggesting that strychnobrasiline derivative alkaloids might exhibit an antineoplastic activity.

On building methodological and theoretical frameworks to examine the interrelationships between environmental change and armed conflict

NASA Astrophysics Data System (ADS)

Van Den Hoek, J.

2014-12-01

Relationships between environmental change and armed conflict have long been studied. Sometimes referred to as 'warfare' or 'conflict' ecology, much of this scholarship has come in response to local-level perceptions of landscape or livelihood changes that result from regional armed conflict. However, such studies have, first, typically focused on spatiotemporally acute and readily detectable environmental change, like deforestation, to the exclusion of protracted and more subtle environmental changes, like agricultural degradation; second, been limited to situational conflicts or circumstances, thereby inhibiting broader theoretical development; and, third, often only considered the environmental consequences rather than the environmental or climatic circumstances that may contribute to conflict. As a result, there is little opportunity for methodological or theoretical cohesion between studies. In this presentation, I synthesize findings from three case studies examining the interrelationships between agricultural change and armed conflict in the semi-arid landscapes of northwest Pakistan, Palestine, and southern Syria. Using coarse through very high resolution remotely sensed imagery, socio-economic and demographic data, conflict databases, open-source programming, and building on theoretical underpinnings of political ecology and conflict studies, I present methods and modeling approaches that aid in overcoming data scarcity and disparity between scales of analysis and integrate environmental and conflict data in spatiotemporally explicit ways. Results from these case studies illuminate the interrelationships between both protracted and acute agricultural change and armed conflict, and have broad relevance for understanding the means by which environment, conflict, and livelihoods are linked, a nexus that will only become tighter with the advance of global climate change.

Growth Life of Surface Cracks in the Rail Web

DOT National Transportation Integrated Search

1989-01-01

The results of a theoretical study of the propagation behavior of surface cracks in the web of railroad rails are presented. Two fracture mechanics models are presented: (1) a conventional LEFM model of an elliptical surface crack of constant aspect ...

Internationalization, Globalization and Relationship Networks as an Epistemological Framework Based on Comparative Studies in Education

ERIC Educational Resources Information Center

García, Amelia Molina; Lara, José Luis Horacio Andrade

2016-01-01

In this paper we present some thoughts on the epistemological framework of comparative studies in education. We present some concepts on the internationalization, globalization and inter-relation networks, based on Jürgen Schriewer, Immanuel Wallerstein, and Norbert Elias's theoretical concepts. These reflections were built within the framework of…

Vagal activity is quadratically related to prosocial traits, prosocial emotions, and observer perceptions of prosociality.

PubMed

Kogan, Aleksandr; Oveis, Christopher; Carr, Evan W; Gruber, June; Mauss, Iris B; Shallcross, Amanda; Impett, Emily A; van der Lowe, Ilmo; Hui, Bryant; Cheng, Cecilia; Keltner, Dacher

2014-12-01

In the present article, we introduce the quadratic vagal activity-prosociality hypothesis, a theoretical framework for understanding the vagus nerve's involvement in prosociality. We argue that vagus nerve activity supports prosocial behavior by regulating physiological systems that enable emotional expression, empathy for others' mental and emotional states, the regulation of one's own distress, and the experience of positive emotions. However, we contend that extremely high levels of vagal activity can be detrimental to prosociality. We present 3 studies providing support for our model, finding consistent evidence of a quadratic relationship between respiratory sinus arrhythmia--the degree to which the vagus nerve modulates the heart rate--and prosociality. Individual differences in vagal activity were quadratically related to prosocial traits (Study 1), prosocial emotions (Study 2), and outside ratings of prosociality by complete strangers (Study 3). Thus, too much or too little vagal activity appears to be detrimental to prosociality. The present article provides the 1st theoretical and empirical account of the nonlinear relationship between vagal activity and prosociality.

Theoretical and experimental studies on vibrational and nonlinear optic properties of guanidinium 3-nitrobenzoate. Differences and similarity between guanidinium 3-nitrobenzoate and guanidinium 4-nitrobenzoate complexes

NASA Astrophysics Data System (ADS)

Drozd, Marek

2018-03-01

According to literature data two structures of guanidine with nitrobenzoic acids are known. For guanidinium 4-nitrobenzoate the detailed studies of X-ray structure, vibrational and theoretical properties were performed. This compound was classified as second harmonic generator with efficiency of 3.3 times that KDP, standard crystal. On the contrary to mentioned above results for the guanidinium 3-nitrobenzoate the basic X-ray diffraction study was performed, only. On the basis of established crystallographic results, the detailed investigation of geometry and vibrational properties were made on the basis of theoretical calculation. According to this data the equilibrium geometry of investigated molecule was established. On the basis of this calculation the detailed computational studies of vibrational properties were performed. The theoretical IR and Raman frequencies, intensities and PED analysis are presented. Additionally, the NBO charges, HOMO and LUMO shapes and NLO properties of titled crystal were calculated. On the basis of these results the crystal was classified as second order generator in NLO but with bigger efficiency that guanidinium 4-nitorobenzoate compound. The obtained data are compared with experimental crystallographic and vibrational results for real crystal of guanidinium 3-nitrobenzoate. Additionally, the theoretical vibrational spectra are compared with literature calculations of guanidinium 4-nitrobenzoate compound.

Theoretical Dipole Moment for the X211 State of NO

NASA Technical Reports Server (NTRS)

Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.; Partridge, Harry; Arnold, James O. (Technical Monitor)

1994-01-01

The dipole moment function for the X(sup 2)II state of NO is studied as a function of the completeness in both the one- and n-particle spaces. Einstein coefficients are presented that are significantly more accurate than previous tabulations for the higher vibrational levels. The theoretical values give considerable insight into the limitations of recently published ratios of Einstein coefficients measured by spectrally resolved infrared chemiluminescence.

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

Tschudi, T.; Herden, A.; Goltz, J.

A theoretical and experimental study of two- and four-wave mixing in photorefractive crystals (BaTiO/sub 3/) is presented, giving special priority to image amplification in optical information processing systems.

Charts for Estimating Tail-rotor Contribution to Helicopter Directional Stability and Control in Low-Speed Flight

NASA Technical Reports Server (NTRS)

Amer, Kenneth B; Gessow, Alfred

1955-01-01

Theoretically derived charts and equations are presented by which tail-rotor design studies of directional trim and control response at low forward speed can be conveniently made. The charts can also be used to obtain the main-rotor stability derivatives of thrust with respect to collective pitch and angle of attack at low forward speeds. The use of the charts and equations for tail-rotor design studies is illustrated. Comparisons between theoretical and experimental results are presented. The charts indicate, and flight tests confirm, that the region of vortex roughness which is familiar for the main rotor is also encountered by the tail rotor and that prolonged operation at the corresponding flight conditions would be difficult.

Study of a coronagraphic mask using evanescent waves.

PubMed

Buisset, Christophe; Rabbia, Yves; Lepine, Thierry; Alagao, Mary-Angelie; Ducrot, Elsa; Poshyachinda, Saran; Soonthornthum, Boonrucksar

2017-04-03

The evanescent wave coronagraph (EvWaCo) is a specific kind of band-limited coronagraph using the frustrated total internal reflection phenomenon to produce the coronagraphic effect (removing starlight from the image plane in order to make the stellar environment detectable). In this paper, we present a theoretical and experimental study of the EvWaCo coronagraphic mask. First, we calculate the theoretical transmission and we show that this mask is partially achromatic. Then, we present the experimental results obtained in unpolarized light at the wavelength λ≈900 nm and relative spectral bandwidth Δλ/λ≈6%. In particular, we show that the coronagraph provides a contrast down to a few 10^-6 at an angular distance of about ten Airy radii.

Where can I find consolation? A theoretical analysis of the meaning of consolation as experienced by job in the Book of Job in the Hebrew Bible.

PubMed

Roxberg, Åsa; Brunt, David; Rask, Mikael; da Silva, António Barbosa

2013-03-01

The aim of the study was to explore the meaning of consolation as experienced by Job in the Book of Job and as presented in literature and how consolation relates to suffering and care. The study's theoretical design applied Ricoeur's view on phenomenology and hermeneutics. The resulting themes were as follows: consolation that is present, that originates in confrontation, that keeps suffering at a distance, that does not alleviate suffering, that originates in experience from giving comfort, and that facilitates a change of perspective. The authentic and caring consolation accepts the sufferer's incomprehensible "otherness" but however provides no answers about how to console.

Stalling of Helicopter Blades

NASA Technical Reports Server (NTRS)

Gustafson, F B; Myers, G C , Jr

1946-01-01

Theoretical studies have predicted that operation of helicopter rotor beyond certain combinations of thrust, forward speed, and rotational speed might be prevented by rapidly increasing stalling of the retreating blade. The same studies also indicate that the efficiency of the rotor will increase until these limits are reached or closely approached, so that it is desirable to design helicopter rotors for operation close to the limits imposed by blade stalling. Inasmuch as the theoretical predictions of blade stalling involve numerous approximations and assumptions, an experimental investigation was needed to determine whether, in actual practice, the stall did occur and spread as predicted and to establish the amount of stalling that could be present without severe vibration or control difficulties being introduced. This report presents the results of such an investigation.

Theoretical study of dissociative recombination of Cl{sub 2}{sup +}

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

Zhang Mingwu; Graduate School of Chinese Academy of Sciences, Beijing 100039; Department of Physics, Stockholm University, S-106 91 Stockholm

Theoretical studies of low-energy electron collisions with Cl{sub 2}{sup +} leading to direct dissociative recombination are presented. The relevant potential energy curves and autoionization widths are calculated by combining electron scattering calculations using the complex Kohn variational method with multireference configuration interaction structure calculations. The dynamics on the four lowest resonant states of all symmetries is studied by the solution of a driven Schroedinger equation. The thermal rate coefficient for dissociative recombination of Cl{sub 2}{sup +} is calculated and the influence on the thermal rate coefficient from vibrational excited target ions is investigated.

Gravity-darkening exponents in semi-detached binary systems from their photometric observations. II.

NASA Astrophysics Data System (ADS)

Djurašević, G.; Rovithis-Livaniou, H.; Rovithis, P.; Georgiades, N.; Erkapić, S.; Pavlović, R.

2006-01-01

This second part of our study concerning gravity-darkening presents the results for 8 semi-detached close binary systems. From the light-curve analysis of these systems the exponent of the gravity-darkening (GDE) for the Roche lobe filling components has been empirically derived. The method used for the light-curve analysis is based on Roche geometry, and enables simultaneous estimation of the systems' parameters and the gravity-darkening exponents. Our analysis is restricted to the black-body approximation which can influence in some degree the parameter estimation. The results of our analysis are: 1) For four of the systems, namely: TX UMa, β Per, AW Cam and TW Cas, there is a very good agreement between empirically estimated and theoretically predicted values for purely convective envelopes. 2) For the AI Dra system, the estimated value of gravity-darkening exponent is greater, and for UX Her, TW And and XZ Pup lesser than corresponding theoretical predictions, but for all mentioned systems the obtained values of the gravity-darkening exponent are quite close to the theoretically expected values. 3) Our analysis has proved generally that with the correction of the previously estimated mass ratios of the components within some of the analysed systems, the theoretical predictions of the gravity-darkening exponents for stars with convective envelopes are highly reliable. The anomalous values of the GDE found in some earlier studies of these systems can be considered as the consequence of the inappropriate method used to estimate the GDE. 4) The empirical estimations of GDE given in Paper I and in the present study indicate that in the light-curve analysis one can apply the recent theoretical predictions of GDE with high confidence for stars with both convective and radiative envelopes.

Full-dimensional analytical potential energy surface describing the gas-phase Cl + C2H6 reaction and kinetics study of rate constants and kinetic isotope effects.

PubMed

Rangel, Cipriano; Espinosa-Garcia, Joaquin

2018-02-07

Within the Born-Oppenheimer approximation a full-dimensional analytical potential energy surface, PES-2017, was developed for the gas-phase hydrogen abstraction reaction between the chlorine atom and ethane, which is a nine body system. This surface presents a valence-bond/molecular mechanics functional form dependent on 60 parameters and is fitted to high-level ab initio calculations. This reaction presents little exothermicity, -2.30 kcal mol -1 , with a low height barrier, 2.44 kcal mol -1 , and intermediate complexes in the entrance and exit channels. We found that the energetic description was strongly dependent on the ab initio level used and it presented a very flat topology in the entrance channel, which represents a theoretical challenge in the fitting process. In general, PES-2017 reproduces the ab initio information used as input, which is merely a test of self-consistency. As a first test of the quality of the PES-2017, a theoretical kinetics study was performed in the temperature range 200-1400 K using two approaches, i.e. the variational transition-state theory and quasi-classical trajectory calculations, with spin-orbit effects. The rate constants show reasonable agreement with experiments in the whole temperature range, with the largest differences at the lowest temperatures, and this behaviour agrees with previous theoretical studies, thus indicating the inherent difficulties in the theoretical simulation of the kinetics of the title reaction. Different sources of error were analysed, such as the limitations of the PES and theoretical methods, recrossing effects, and the tunnelling effect, which is negligible in this reaction, and the manner in which the spin-orbit effects were included in this non-relativistic study. We found that the variation of spin-orbit coupling along the reaction path, and the influence of the reactivity of the excited Cl( 2 P 1/2 ) state, have relative importance, but do not explain the whole discrepancy. Finally, the activation energy and the kinetics isotope effects reproduce the experimental information.

How the bimodal format of presentation affects working memory: an overview.

PubMed

Mastroberardino, Serena; Santangelo, Valerio; Botta, Fabiano; Marucci, Francesco S; Olivetti Belardinelli, Marta

2008-03-01

The best format in which information that has to be recalled is presented has been investigated in several studies, which focused on the impact of bimodal stimulation on working memory performance. An enhancement of participant's performance in terms of correct recall has been repeatedly found, when bimodal formats of presentation (i.e., audiovisual) were compared to unimodal formats (i.e, either visual or auditory), in providing implications for multimedial learning. Several theoretical frameworks have been suggested in order to account for the bimodal advantage, ranging from those emphasizing early stages of processing (such as automatic alerting effects or multisensory integration processes) to those centred on late stages of processing (as postulated by the dual coding theory). The aim of this paper is to review previous contributions to this topic, providing a comprehensive theoretical framework, which is updated by the latest empirical studies.

On previous and present investigations of resonance gamma-ray interaction with nuclei at the Institute of Theoretical and Experimental Physics (ITEP, Moscow)

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

Davydov, A. V.

A brief survey of theoretical and experimental work that is devoted to studying the resonance absorption and scattering of gamma rays by nuclei and which was initiated at the Institute of Theoretical and Experimental Physics (ITEP, Moscow) in the 1950s and has been continued to date is given. Investigations of various versions of interaction in beta decay, magnetic-field-perturbed angular distributions of resonantly scattered gamma rays, the problem of the Moessbauer gamma resonance of long-lived isomeric states of nuclei, and the resonance scattering of annihilation photons by nuclei are described.

Theoretical Problems in Materials Science

NASA Technical Reports Server (NTRS)

Langer, J. S.; Glicksman, M. E.

1985-01-01

Interactions between theoretical physics and material sciences to identify problems of common interest in which some of the powerful theoretical approaches developed for other branches of physics may be applied to problems in materials science are presented. A unique structure was identified in rapidly quenched Al-14% Mn. The material has long-range directed bonds with icosahedral symmetry which does not form a regular structure but instead forms an amorphous-like quasiperiodic structure. Finite volume fractions of second phase material is advanced and is coupled with nucleation theory to describe the formation and structure of precipitating phases in alloys. Application of the theory of pattern formation to the problem of dendrite formation is studied.

Togetherness and Play under the Same Roof: Children's Perceptions about Families

ERIC Educational Resources Information Center

Oliveira-Formosinho, Julia

2009-01-01

The purpose of the research study presented in this article is to look at the ways that a specific group of children think about their families and to develop contextualized methods for listening to children's perspectives about their families. It starts with a brief presentation of the theoretical and pedagogical context where the study has been…

Description of alpha-nucleus interaction cross sections for cosmic ray shielding studies

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

1993-01-01

Nuclear interactions of high-energy alpha particles with target nuclei important for cosmic ray studies are discussed. Models for elastic, quasi-elastic, and breakup reactions are presented and compared with experimental data. Energy-dependent interaction cross sections and secondary spectra are presented based on theoretical models and the limited experimental data base.

JPRS Report, Soviet Union, World Economy & International Relations, No. 6, June 1989.

DTIC Science & Technology

1989-10-05

analysis of the discussions, held in France, is presented in the article "On Single European Market" written by I. EGOROV, our Paris correspondent... analysis that it studies current problems of international politics. But what are the basic theoretical principles of the new political thinking...loyalty to Marxism-Leninism is tested by the ability of its followers to use its theoretical and methodological principles for the creative analysis of

A Diagnostic Marker to Discriminate Childhood Apraxia of Speech from Speech Delay: III. Theoretical Coherence of the Pause Marker with Speech Processing Deficits in Childhood Apraxia of Speech

ERIC Educational Resources Information Center

Shriberg, Lawrence D.; Strand, Edythe A.; Fourakis, Marios; Jakielski, Kathy J.; Hall, Sheryl D.; Karlsson, Heather B.; Mabie, Heather L.; McSweeny, Jane L.; Tilkens, Christie M.; Wilson, David L.

2017-01-01

Purpose: Previous articles in this supplement described rationale for and development of the pause marker (PM), a diagnostic marker of childhood apraxia of speech (CAS), and studies supporting its validity and reliability. The present article assesses the theoretical coherence of the PM with speech processing deficits in CAS. Method: PM and other…

Ultimate Gradient Limitation in Niobium Superconducting Accelerating Cavities

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

Checchin, Mattia; Grassellino, Anna; Martinello, Martina

2016-06-01

The present study is addressed to the theoretical description of the ultimate gradient limitation in SRF cavities. Our intent is to exploit experimental data to confirm models which provide feed-backs on how to improve the current state-of-art. New theoretical insight on the cavities limiting factor can be suitable to improve the quench field of N-doped cavities, and therefore to take advantage of high Q 0 at high gradients.

Vibration Prediction Model for Floating-Slab Rail Transit Track

DOT National Transportation Integrated Search

1975-08-01

This report presents the theoretical development of a model to predict the vibration reduction by floating-slab tracks in subway tunnels. Data from a field study in New York City are also presented. The report is one of three reports dealing with noi...

Theoretical Investigation of Regioselectivity and Stereoselectivity in AIBN/HSnBu3-Mediated Radical Cyclization of N-(2-Iodo-4,6-dimethylphenyl)-N,2-dimethyl-(2E)-butenamide.

PubMed

Li, Bai-Jian; Zhong, Hua; Yu, Hai-Tao

2016-12-22

In this study, we employed the density functional method to simulate AIBN/HSnBu 3 -mediated radical cyclizations with different axially chiral conformers of N-(2-iodo-4,6-dimethylphenyl)-N,2-dimethyl-(2E)-butenamide as substrates. We constructed a reaction potential energy profile using the Gibbs free energies of the located stationary points. The thermodynamic and kinetic data of the profile were further used to evaluate the regioselectivity, stereoselectivity, and product distribution of the cyclizations. Additionally, we compared the present HSnBu 3 -mediated radical cyclization with the experimentally available Heck reaction and found that such a radical cyclization can convert (M,Z) and (P,Z) o-iodoanilide substrates to centrally chiral products with high chirality transfer. The goal of this study was to estimate the practicality of theoretically predicting the memory of chirality in such radical cyclizations. The present results can provide a strategy from a theoretical viewpoint for experimentally synthesizing highly stereoselective carbocyclic and heterocyclic compounds using radical cyclization methods.

Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds

PubMed Central

Castro, Maria Eugenia; Percino, Maria Judith; Chapela, Victor M.; Ceron, Margarita; Soriano-Moro, Guillermo; Lopez-Cruz, Jorge; Melendez, Francisco J.

2013-01-01

A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)] pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases. For theoretical UV-Vis and 1H NMR spectra, the Time-Dependent DFT (TD-DFT) and the Gauge-Including Atomic Orbital (GIAO) methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl-substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. 1H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and 1H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds. PMID:23429190

Theoretical Problems in High Resolution Solar Physics, 2

NASA Technical Reports Server (NTRS)

Athay, G. (Editor); Spicer, D. S. (Editor)

1987-01-01

The Science Working Group for the High Resolution Solar Observatory (HRSO) laid plans beginning in 1984 for a series of workshops designed to stimulate a broadbased input from the scientific community to the HRSO mission. These workshops have the dual objectives of encouraging an early start on the difficult theoretical problems in radiative transfer, magnetohydrodynamics, and plasma physics that will be posed by the HRSO data, and maintaining current discussions of results in high resolution solar studies. This workshop was the second in the series. The workshop format presented invited review papers during the formal sessions and contributed poster papers for discussions during open periods. Both are presented.

The Interaction-Activity Connection

NASA Technical Reports Server (NTRS)

Borne, Kirk D.

1996-01-01

A review is presented of the numerous studies that have been undertaken to investigate the likely interaction-activity connection among galaxies. Both observational evidence and theoretical supporting models are reviewed. Some specific examples of "interactive" galaxies from the author's own research are presented: (a) the collision-induced AGN (Active Galactic Nuclei) activity in the radio jet source 3C278; and (b) the collision-induced starburst activity in the spectacular "Cartwheel" ring galaxy. Some comments are offered concerning some of the more promising theoretical investigations that are now taking place. A few words of warning are also offered about the possible misinterpretation of putative collision-induced morphologies among some galaxy samples.

Theoretical study of diaquamalonatozinc(II) single crystal for applications in non-linear optical devices

NASA Astrophysics Data System (ADS)

Chakraborty, Mitesh; Rai, Vineet Kumar

2017-12-01

The aim of the present paper is to employ theoretical methods to investigate the zero field splitting (ZFS) parameter and to investigate the position of the dopant in the host. These theoretical calculations have been compared with the empirical results. The superposition model (SPM) with the microscopic spin-Hamiltonian (MSH) theory and the coefficient of fractional parentage have been employed to investigate the dopant manganese(II) ion substitution in the diaquamalonatozinc(II) (DAMZ) single crystal. The magnetic parameters, viz. g-tensor and D-tensor, has been determined by using the ORCA program package developed by F Neese et al. The unrestricted Kohn-Sham orbitals-based Pederson-Khanna (PK) as the unperturbed wave function is observed to be the most suitable for the computational calculation of spin-orbit tensor (D^{SO}) of the axial ZFS parameter D. The effects of spin-spin dipolar couplings are taken into account. The unrestricted natural orbital (UNO) is used for the calculation of spin-spin dipolar contributions to the ZFS tensor. A comparative study of the quantum mechanical treatment of Pederson-Khanna (PK) with coupled perturbation (CP) is reported in the present study. The unrestricted Kohn-Sham-based natural orbital with Pederson-Khanna-type of perturbation approach validates the experimental results in the evaluation of ZFS parameters. The theoretical results are appropriate with the experimental ones and indicate the interstitial occupancy of Mn^{2+} ion in the host matrix.

Spectral and structural studies of the anti-cancer drug Flutamide by density functional theoretical method

NASA Astrophysics Data System (ADS)

Mariappan, G.; Sundaraganesan, N.

2014-01-01

A comprehensive screening of the more recent DFT theoretical approach to structural analysis is presented in this section of theoretical structural analysis. The chemical name of 2-methyl-N-[4-nitro-3-(trifluoromethyl)phenyl]-propanamide is usually called as Flutamide (In the present study it is abbreviated as FLT) and is an important and efficacious drug in the treatment of anti-cancer resistant. The molecular geometry, vibrational spectra, electronic and NMR spectral interpretation of Flutamide have been studied with the aid of density functional theory method (DFT). The vibrational assignments of the normal modes were performed on the basis of the PED calculations using the VEDA 4 program. Comparison of computational results with X-ray diffraction results of Flutamide allowed the evaluation of structure predictions and confirmed B3LYP/6-31G(d,p) as accurate for structure determination. Application of scaling factors for IR and Raman frequency predictions showed good agreement with experimental values. This is supported the assignment of the major contributors of the vibration modes of the title compound. Stability of the molecule arising from hyperconjugative interactions leading to its bioactivity, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. NMR chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. The comparison of measured FTIR, FT-Raman, and UV-Visible data to calculated values allowed assignment of major spectral features of the title molecule. Besides, Frontier molecular orbital analyze was also investigated using theoretical calculations.

Quality Assessment of Internationalised Studies: Theory and Practice

ERIC Educational Resources Information Center

Juknyte-Petreikiene, Inga

2013-01-01

The article reviews forms of higher education internationalisation at an institutional level. The relevance of theoretical background of internationalised study quality assessment is highlighted and definitions of internationalised studies quality are presented. Existing methods of assessment of higher education internationalisation are criticised…

Conformational equilibrium of phenylacetic acid and its halogenated analogues through theoretical studies, NMR and IR spectroscopy

NASA Astrophysics Data System (ADS)

Levandowski, Mariana N.; Rozada, Thiago C.; Melo, Ulisses Z.; Basso, Ernani A.; Fiorin, Barbara C.

2017-03-01

This paper presents a study on the conformational preferences of phenylacetic acid (PA) and its halogenated analogues (FPA, CPA, BPA). To clarify the effects that rule these molecules' behaviour, theoretical calculations were used, for both the isolated phase and solution, combined with nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. Most conformations of phenylacetic acid and its halogenated derivatives are stabilized through the hyperconjugative effect, which rules the conformational preference. NMR analyses showed that even with the variation in medium polarity, there was no significant change in the conformation population. Infrared spectroscopy showed similar results for all compounds under study. In most spectra, two bands were found through the carbonyl deconvolution, which is in accordance with the theoretical data. It was possible to prove that variation in the nature of the substituent in the ortho position had no significant influence on the conformational equilibrium.

Mechanism of Flutter A Theoretical and Experimental Investigation of the Flutter Problem

NASA Technical Reports Server (NTRS)

Theodorsen, Theodore; Garrick, I E

1940-01-01

The results of the basic flutter theory originally devised in 1934 and published as NACA Technical Report no. 496 are presented in a simpler and more complete form convenient for further studies. The paper attempts to facilitate the judgement of flutter problems by a systematic survey of the theoretical effects of the various parameters. A large number of experiments were conducted on cantilever wings, with and without ailerons, in the NACA high-speed wind tunnel for the purpose of verifying the theory and to study its adaptability to three-dimensional problems. The experiments included studies on wing taper ratios, nacelles, attached floats, and external bracings. The essential effects in the transition to the three-dimensional problem have been established. Of particular interest is the existence of specific flutter modes as distinguished from ordinary vibration modes. It is shown that there exists a remarkable agreement between theoretical and experimental results.

Optical spectra and band structure of Ag(x)Ga(x)Ge(1-x)Se2 (x = 0.333, 0.250, 0.200, 0.167) single crystals: experiment and theory.

PubMed

Reshak, A H; Parasyuk, O V; Fedorchuk, A O; Kamarudin, H; Auluck, S; Chyský, J

2013-12-05

Theoretical and experimental studies of the Ag(x)Ga(x)Ge(1-x)Se2 (x = 0.333, 0.250, 0.200, 0.167) single crystals are performed. These crystals possess a lot of intrinsic defects which are responsible for their optoelectronic features. The theoretical investigations were performed by means of DFT calculations using different exchange-correlation potentials. The experimental studies were carried out using the modulated VUV ellipsometry for dielectric constants and birefringence studies. The comparison of the structure obtained from X-ray with the theoretically optimized structure is presented. The crucial role of the intrinsic defect states is manifested in the choice of the exchange correlation potential used. The data may be applicable for a large number of the ternary chalcogenides which are sensitive to the presence of the local disordered states near the band edges.

Rectilinear six-dimensional ionization cooling channel for a muon collider: A theoretical and numerical study

DOE PAGES

Stratakis, Diktys; Palmer, Robert B.

2015-03-06

A Muon Collider requires a reduction of the six-dimensional emittance of the captured muon beam by several orders of magnitude. In this study, we describe a novel rectilinear cooling scheme that should meet this requirement. First, we present the conceptual design of our proposed scheme wherein we detail its basic features. Then, we establish the theoretical framework to predict and evaluate the performance of ionization cooling channels and discuss its application to our specific case. In conclusion, we present the first end-to-end simulation of 6D cooling for a Muon Collider and show a notable reduction of the 6D emittance bymore » five orders of magnitude. We find good agreement between simulation and theory.« less

In the Rearview Mirror: Social Skill Development in Deaf Youth, 1990-2015.

PubMed

Cawthon, Stephanie W; Fink, Bentley; Schoffstall, Sarah; Wendel, Erica

2018-01-01

Social skills are a vehicle by which individuals negotiate important relationships. The present article presents historical data on how social skills in deaf students were conceptualized and studied empirically during the period 1990-2015. Using a structured literature review approach, the researchers coded 266 articles for theoretical frameworks used and constructs studied. The vast majority of articles did not explicitly align with a specific theoretical framework. Of the 37 that did, most focused on socioemotional and cognitive frameworks, while a minority drew from frameworks focusing on attitudes, developmental theories, or ecological systems theory. In addition, 315 social-skill constructs were coded across the data set; the majority focused on socioemotional functioning. Trends in findings across the past quarter century and implications for research and practice are examined.

Simplified model to describe the dissociative recombination of linear polyatomic ions of astrophysical interest

NASA Astrophysics Data System (ADS)

Douguet, N.; Fonseca dos Santos, S.; Kokoouline, V.; Orel, A. E.

2015-01-01

We present results of a theoretical study on dissociative recombination of the HCNH+, HCO+ and N2H+ linear polyatomic ions at low energies using a simple theoretical model. In the present study, the indirect mechanism for recombination proceeds through the capture of the incoming electron in excited vibrational Rydberg states attached to the degenerate transverse modes of the linear ions. The strength of the non-adiabatic coupling responsible for dissociative recombination is determined directly from the near-threshold scattering matrix obtained numerically using the complex Kohn variational method. The final cross sections for the process are compared with available experimental data. It is demonstrated that at low collision energies, the major contribution to the dissociative recombination cross section is due to the indirect mechanism.

Refractive index of B1-xGaxN semiconductors

NASA Astrophysics Data System (ADS)

Vyas, P. S.; Baria, J. K.; Jivani, A. R.; Gajjar, P. N.; Jani, A. R.

2013-06-01

A theoretical procedure is presented for the study of refractive index of ternary alloy B1-xGaxN. The calculations based on the pseudopotential formalism in which local potential coupled with the virtual crystal approximation (VCA) is applied to evaluate energy band gap at point X on the Jones-zone face, refractive index for the entire range of the alloy composition x of the ternary alloy B1-xGaxN. To include exchange and correlation effects, local field correction function due to Nagy is employed. Our results for parent compounds are compared to experiment and other available theoretical findings and showed generally good agreement. During present study it is found that the refractive index of the ternary alloy B1-xGaxN has minimum value at gallium concentration x = 0.4.

The Concept of “Metaemotion”: What is There to Learn From Research on Metacognition?

PubMed Central

Norman, Elisabeth; Furnes, Bjarte

2014-01-01

We first present a selection of vignette examples from empirical psychological research to illustrate how the phenomenon of metaemotion (Gottman, Katz, & Hooven, 1996; Mendonça, 2013) is studied within different domains of psychology. We then present a theoretical distinction which has been made between three facets of metacognition, namely metacognitive experiences, metacognitive knowledge, and metacognitive strategies (e.g., Efklides, 2008; Flavell, 1979). Referring back to the vignette examples from metaemotion research, we argue that a similar distinction can be drawn between three facets of metaemotion, namely metaemotional experiences, metaemotional knowledge, and metaemotional strategies. We argue that this distinction clarifies some of the unresolved issues in metaemotion research, and therefore has important implications for the study of metaemotion, both methodologically and theoretically. PMID:27110281

Becoming Independent Storytellers: Modeling Children's Development of Narrative Macrostructure

ERIC Educational Resources Information Center

Kelly, Kimberly Reynolds; Bailey, Alison Louise

2013-01-01

For parents to provide effective support for their children's language development, they must be attuned to their child's changing abilities. This study presents a theoretically driven strategy that addresses a methodological challenge present when tracking longitudinally the cessation or "fading" of behaviors by capturing withdrawal of…

Quantity and Quality of Motivational Regulation among University Students

ERIC Educational Resources Information Center

Engelschalk, Tobias; Steuer, Gabriele; Dresel, Markus

2017-01-01

Effective regulation of motivation can be theoretically explained by both the extent of motivational regulation strategies used (quantity) and their optimal implementation (quality). Researchers have not yet analysed the significance of both aspects for learning success simultaneously. In the present study, 188 students were presented with…

A Brief History of the Institute of Theoretical Physics in the Chinese Academy of Sciences since 1978

NASA Astrophysics Data System (ADS)

Jinyan, Liu

2014-03-01

The Institute of Theoretical Physics (ITP), Chinese academy of Sciences (CAS), founded in June 1978, is a specialized institute studying major issues in the fundamental research of theoretical physics. ITP has played an important role in the development of theoretical physics in China, especially in organizing and undertaking major national projects, expanding international exchanges and cooperation, and nurturing advanced researchers. My presentation will examine the reasons why ITP was founded in 1978 and why Peng Huanwu and Zhou Guangzhao, two prominent Chinese theorists, were chosen as the first and second directors of ITP. Moreover, I will summarize ITP's scientific activities and achievements in the past 35 years. Last but not least, I will compare ITP with university physics departments and explore its unique characters (both strength and weakness).

Theoretical study in carrier mobility of two-dimensional materials

NASA Astrophysics Data System (ADS)

Huang, R.

2017-09-01

Recently, the theoretical prediction on carrier mobility of two-dimensional (2D) materials has aroused wild attention. At present, there is still a large gap between the theoretical prediction and the device performance of the semiconductor based on the 2D layer semiconductor materials such as graphene. It is particularly important to theoretically design and screen the high-performance 2D layered semiconductor materials with suitable band gap and high carrier mobility. This paper introduces some 2D materials with fine properties and deduces the formula for mobility of the isotropic materials on the basis of the deformation potential theory and Fermic golden rule under acoustic phonon scattering conditions, and then discusses the carrier mobility of anisotropic materials with Dirac cones. We point out the misconceptions in the existing literature and discuss the correct ones.

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

Galperin, Michael

The progress of experimental techniques at the nanoscale in the last decade made optical measurements in current-carrying nanojunctions a reality, thus indicating the emergence of a new field of research coined optoelectronics. Optical spectroscopy of open nonequilibrium systems is a natural meeting point for (at least) two research areas: nonlinear optical spectroscopy and quantum transport, each with its own theoretical toolbox. We review recent progress in the field comparing theoretical treatments of optical response in nanojunctions as is accepted in nonlinear spectroscopy and quantum transport communities. A unified theoretical description of spectroscopy in nanojunctions is presented. Here, we argue thatmore » theoretical approaches of the quantum transport community (and in particular, the Green function based considerations) yield a convenient tool for optoelectronics when the radiation field is treated classically, and that differences between the toolboxes may become critical when studying the quantum radiation field in junctions.« less

Autonomous Motivation and Pro-Environmental Behaviours among Bedouin Students in Israel: A Self-Determination Theory Perspective

ERIC Educational Resources Information Center

Kaplan, Haya; Madjar, Nir

2015-01-01

Promoting pro-environmental behaviours (PEBs) among students is a major concern for educators. The present article presents an educational program based on a self-determination theory framework (SDT; Deci & Ryan, 2000) and a study demonstrating that working according to the theoretical principles presented in the program leads to the desired…

The Differential Impact of Observational Learning and Practice-Based Learning on the Development of Oral Presentation Skills in Higher Education

ERIC Educational Resources Information Center

De Grez, Luc; Valcke, Martin; Roozen, Irene

2014-01-01

The present study focuses on the design and evaluation of an innovative instructional approach to developing oral presentation skills. The intervention builds on the observational learning theoretical perspective. This perspective is contrasted with the traditional training and practice approach. Two sequencing approaches--learners starting with…

Detection of free nickel monocarbonyl, NiCO: rotational spectrum and structure.

PubMed

Yamazaki, Emi; Okabayashi, Toshiaki; Tanimoto, Mitsutoshi

2004-02-04

Unsaturated transition metal carbonyls are important in processes such as organometallic synthesis, homogeneous catalysis, and photochemical decomposition of organometallics. In particular, a metal monocarbonyl offers a zeroth-order model for interpreting the chemisorption of a CO molecule on a metal surface in catalytic activation processes. Quite large numbers of theoretical papers have appeared which predict spectroscopic and structural properties of transition metal carbonyls. The nickel monocarbonyl NiCO has been one of the metal carbonyls most extensively studied by the theoretical calculations. At least 50 theoretical studies have been published on this simplest transition metal carbonyl up to the present time. However, experimental evidence of NiCO is much more sparse than theoretical predictions, and the actual structure of NiCO has never been determined by any experimental methods. This Communication reports the first preparation of free nickel monocarbonyl and observation of its rotational transitions. The NiCO molecule was generated by the sputtering reaction of a Ni cathode in the presence of CO. The accurate bond lengths of Ni-C and C-O were experimentally determined from isotopic data and were compared with the theoretical predictions for the first time.

Novel endophytic yeast Rhodotorula mucilaginosa strain PTD3 I: production of xylitol and ethanol.

PubMed

Bura, Renata; Vajzovic, Azra; Doty, Sharon L

2012-07-01

An endophytic yeast, Rhodotorula mucilaginosa strain PTD3, that was isolated from stems of hybrid poplar was found to be capable of production of xylitol from xylose, of ethanol from glucose, galactose, and mannose, and of arabitol from arabinose. The utilization of 30 g/L of each of the five sugars during fermentation by PTD3 was studied in liquid batch cultures. Glucose-acclimated PTD3 produced enhanced yields of xylitol (67% of theoretical yield) from xylose and of ethanol (84, 86, and 94% of theoretical yield, respectively) from glucose, galactose, and mannose. Additionally, this yeast was capable of metabolizing high concentrations of mixed sugars (150 g/L), with high yields of xylitol (61% of theoretical yield) and ethanol (83% of theoretical yield). A 1:1 glucose:xylose ratio with 30 g/L of each during double sugar fermentation did not affect PTD3's ability to produce high yields of xylitol (65% of theoretical yield) and ethanol (92% of theoretical yield). Surprisingly, the highest yields of xylitol (76% of theoretical yield) and ethanol (100% of theoretical yield) were observed during fermentation of sugars present in the lignocellulosic hydrolysate obtained after steam pretreatment of a mixture of hybrid poplar and Douglas fir. PTD3 demonstrated an exceptional ability to ferment the hydrolysate, overcome hexose repression of xylose utilization with a short lag period of 10 h, and tolerate sugar degradation products. In direct comparison, PTD3 had higher xylitol yields from the mixed sugar hydrolysate compared with the widely studied and used xylitol producer Candida guilliermondii.

Transforming the Curriculum: Ethnic Studies and Women's Studies.

ERIC Educational Resources Information Center

Butler, Johnnella E., Ed.; Walter, John C., Ed.

This book provides a collection of 19 essays that discuss curricular change in higher education regarding ethnic and women's studies, and presents the theoretical and practical bases for accomplishing this restyling. The papers and authors are as follows: "The Difficult Dialogue of Curriculum Transformation: Ethnic Studies and Women's Studies"…

Ti:sapphire - A theoretical assessment for its spectroscopy

NASA Astrophysics Data System (ADS)

Da Silva, A.; Boschetto, D.; Rax, J. M.; Chériaux, G.

2017-03-01

This article tries to theoretically compute the stimulated emission cross-sections when we know the oscillator strength of a broad material class (dielectric crystals hosting metal-transition impurity atoms). We apply the present approach to Ti:sapphire and check it by computing some emission cross-section curves for both π and σ polarizations. We also set a relationship between oscillator strength and radiative lifetime. Such an approach will allow future parametric studies for Ti:sapphire spectroscopic properties.

Optical properties of YbMnBi2: A type II Weyl semimetal candidate

NASA Astrophysics Data System (ADS)

Pal, A.; Chinotti, M.; Degiorgi, L.; Ren, W. J.; Petrovic, C.

2018-05-01

We discuss our recent optical investigation of YbMnBi2, a representative type II Weyl semimetal, by considering a simple scheme for the electronic structure, which can be embedded within a recent theoretical approach for the calculation of the excitation spectrum. Our study allows us disentangling the generic optical fingerprints of Weyl fermions, which are in broad agreement with the theoretical predictions but also challenge the present understanding of their electrodynamic response.

Research Planning from a Micro-Ecological Perspective: Summary of Interview Study. Educational and Psychological Interactions No. 60.

ERIC Educational Resources Information Center

Bierschenk, Bernhard

Empirical information is presented on how researchers at Swedish institutes of education perceive, structure, and define educational and psychological problems. The collection, evaluation, and presentation of the results of the study were made on the basis of system theoretic assumptions in that the description and analysis of the initial phase of…

Developing Second Language Writing through Scaffolding in the ZPD: A Magazine Project for an Authentic Audience

ERIC Educational Resources Information Center

Schwieter, John W.

2010-01-01

In the present study, Vygotsky's (1978, 1986) sociocultural framework of the zone of proximal development (ZPD) and scaffolding writing (Bodrova & Leong, 1995, 1996; Ross, 1976) are used as the theoretical basis to study the development of second language writing. A course project is presented in which advanced English language learners of Spanish…

A semiclassical study of laser-induced atomic fluorescence from Na2, K2 and NaK

NASA Technical Reports Server (NTRS)

Yuan, J.-M.; Bhattacharyya, D. K.; George, T. F.

1982-01-01

A semiclassical treatment of laser-induced atomic fluorescence for the alkali-dimer systems Na2, K2 and NaK is presented. The variation of the fluorescence intensity with the frequency of the exciting laser photon is studied and a comparison of theoretical results with a set of experimental data is presented.

Students' Perceptions on Environmental Management of HEIs and the Role of Social Capital: A Case Study in the University of the Aegean

ERIC Educational Resources Information Center

Jones, Nikoleta; Roumeliotis, Spiridon; Iosifides, Theodoros; Hatziantoniou, Maria; Sfakianaki, Eleni; Tsigianni, Eleni; Thivaiou, Kalliopi; Biliraki, Athina; Evaggelinos, Kostas

2013-01-01

Purpose: The aim of the present study is to contribute to the discussion introducing the concept of social capital as a significant parameter influencing students' perceptions concerning greening initiatives in HEIs. Design/methodology/approach: A theoretical analysis is presented concerning the possible links of social capital components with…

[Testing of the effect of classic conditioning stimuli in human experiment by means of the transfer of control paradigm].

PubMed

Wolter, J

1999-01-01

Pavlovian conditioning in animals is often evaluated by means of transfer of control experiments. With human subjects, however, only very few studies have been conducted and the outcomes were often not in accordance with theoretical explanations based on studies with animals. A theoretical framework is presented that tries to integrate the results of the human conditioning paradigm and the animal conditioning paradigm as well, with reference to the well-known Yerkes-Dodson law. The experimental study with human subjects (N = 24) confirmed the predictions out of this framework, when a procedure similar to animal research is applied.

The Electrostatic Environments of Mars: Atmospheric Discharges

NASA Technical Reports Server (NTRS)

Calle, Carlos I.; Mackey, Paul J.; Johansen, Michael R.; Hogue, Michael D.; Phillips, James, III; Cox, Rachel E.

2016-01-01

The electrostatic environment on Mars is controlled by its ever present atmospheric dust. Dust devils and dust storms tribocharge this dust. Theoretical studies predict that lightning and/or glow discharges should be present on Mars, but none have been directly observed. Experiments are planned to shed light on this issue.

Theoretical kinetics study of the F((2)P) + NH3 hydrogen abstraction reaction.

PubMed

Espinosa-Garcia, J; Fernandez-Ramos, A; Suleimanov, Y V; Corchado, J C

2014-01-23

The hydrogen abstraction reaction of fluorine with ammonia represents a true chemical challenge because it is very fast, is followed by secondary abstraction reactions, which are also extremely fast, and presents an experimental/theoretical controversy about rate coefficients. Using a previously developed full-dimensional analytical potential energy surface, we found that the F + NH3 → HF + NH2 system is a barrierless reaction with intermediate complexes in the entry and exit channels. In order to understand the reactivity of the title reaction, thermal rate coefficidents were calculated using two approaches: ring polymer molecular dynamics and quasi-classical trajectory calculations, and these were compared with available experimental data for the common temperature range 276-327 K. The theoretical results obtained show behavior practically independent of temperature, reproducing Walther-Wagner's experiment, but in contrast with Persky's more recent experiment. However, quantitatively, our results are 1 order of magnitude larger than those of Walther-Wagner and reasonably agree with the Persky at the lowest temperature, questioning so Walther-Wagner's older data. At present, the reason for this discrepancy is not clear, although we point out some possible reasons in the light of current theoretical calculations.

Theoretical and experimental study of a fiber optic microphone

NASA Technical Reports Server (NTRS)

Hu, Andong; Cuomo, Frank W.; Zuckerwar, Allan J.

1992-01-01

Modifications to condenser microphone theory yield new expressions for the membrane deflections at its center, which provide the basic theory for the fiber optic microphone. The theoretical analysis for the membrane amplitude and the phase response of the fiber optic microphone is given in detail in terms of its basic geometrical quantities. A relevant extension to the original concepts of the optical microphone includes the addition of a backplate with holes similar in design to present condenser microphone technology. This approach generates improved damping characteristics and extended frequency response that were not previously considered. The construction and testing of the improved optical fiber microphone provide experimental data that are in good agreement with the theoretical analysis.

Applications of surface analysis and surface theory in tribology

NASA Technical Reports Server (NTRS)

Ferrante, John

1988-01-01

Tribology, the study of adhesion, friction and wear of materials is a complex field which requires a knowledge of solid state physics, surface physics, chemistry, material science and mechanical engineering. It has been dominated, however, by the more practical need to make equipment work. With the advent of surface analysis and advances in surface and solid state theory, a new dimension has been added to the analysis of interactions at tribological interfaces. In this paper the applications of tribological studies and their limitations are presented. Examples from research at the NASA Lewis Research Center are given. Emphasis is on fundamental studies involving the effects of monolayer coverage and thick films on friction and wear. A summary of the current status of theoretical calculations of defect energetics is presented. In addition, some new theoretical techniques which enable simplified quantitative calculations of adhesion, fracture and friction are discussed.

Applications of surface analysis and surface theory in tribology

NASA Technical Reports Server (NTRS)

Ferrante, John

1989-01-01

Tribology, the study of adhesion, friction and wear of materials, is a complex field which requires a knowledge of solid state physics, surface physics, chemistry, material science, and mechanical engineering. It has been dominated, however, by the more practical need to make equipment work. With the advent of surface analysis and advances in surface and solid-state theory, a new dimension has been added to the analysis of interactions at tribological interfaces. In this paper the applications of tribological studies and their limitations are presented. Examples from research at the NASA Lewis Research Center are given. Emphasis is on fundamental studies involving the effects of monolayer coverage and thick films on friction and wear. A summary of the current status of theoretical calculations of defect energetics is presented. In addition, some new theoretical techniques which enable simplified quantitative calculations of adhesion, fracture, and friction are discussed.

Static tool influence function for fabrication simulation of hexagonal mirror segments for extremely large telescopes.

PubMed

Kim, Dae Wook; Kim, Sug-Whan

2005-02-07

We present a novel simulation technique that offers efficient mass fabrication strategies for 2m class hexagonal mirror segments of extremely large telescopes. As the first of two studies in series, we establish the theoretical basis of the tool influence function (TIF) for precessing tool polishing simulation for non-rotating workpieces. These theoretical TIFs were then used to confirm the reproducibility of the material removal foot-prints (measured TIFs) of the bulged precessing tooling reported elsewhere. This is followed by the reverse-computation technique that traces, employing the simplex search method, the real polishing pressure from the empirical TIF. The technical details, together with the results and implications described here, provide the theoretical tool for material removal essential to the successful polishing simulation which will be reported in the second study.

Photoelectron Angular Distributions of Transition Metal Dioxide Anions - a joint experimental and theoretical study

NASA Astrophysics Data System (ADS)

Iordanov, Ivan; Gunaratne, Dasitha; Harmon, Christopher; Sofo, Jorge; Castleman, A. W., Jr.

2012-02-01

Angular-resolved photoelectron spectroscopy (PES) studies of the MO2- (M=Ti, Zr, Hf, Co, Rh) clusters are presented for the first time along with theoretical calculations of their properties. We confirm previously reported non-angular PES results for the vertical detachment energies (VDE), vibrational energies and geometric structures of these clusters and further explore the effect of the 'lanthanide contraction' on the MO2- clusters by comparing the electronic spectra of 4d and 5d transition metal dioxides. Angular-resolved PES provides the angular momentum contributions to the HOMO of these clusters and we use theoretical calculations to examine the HOMO and compare to our experimental results. First-principles calculations are done using both density functional theory (DFT) and the coupled-cluster, singles, doubles and triples (CCSD(T)) methods.

Problemes theoriques et methodologiques dans l'etude des langues/dialectes en contact aux niveaux macrologique et micrologique = Theoretical and Methodological Issues in the Study of Languages/Dialects in Contact at Macro- and Micro-Logical Levels of Analysis. Proceedings of the International Conference DALE (University of London)/ICRB (Laval University, Quebec)/ICSBT (Vrije Universiteit te Brussel) (London, England, May 23-26, 1985).

ERIC Educational Resources Information Center

Blanc, Michel, Ed.; Hamers, Josiane F., Ed.

Papers from an international conference on the interaction of languages and dialects in contact are presented in this volume. Papers include: "Quelques reflexions sur la variation linguistique"; "The Investigation of 'Language Continuum' and 'Diglossia': A Macrological Case Study and Theoretical Model"; "A Survey of…

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

Sharma, Anupam Deep, E-mail: dr.anupamdeep@yahoo.com; Sinha, M. M.

Perovskite oxides find wide range of applications like oxygen sensors, catalyst support, high frequency capacitors, high temperature superconducting microwave devices, solid state oxide fuel cell (SOFC) etc. LaAlO{sub 3} is one of such type of prominent perovskite oxides and very prominent material for protonic conductions. Therefore knowledge of the thermal properties of LaAlO{sub 3} is most significant. Hence in the present study we have studied phonon density of states and specific heat of LaAlO{sub 3} in cubic structure by applying lattice dynamical theoretical model. The calculated results are interpreted with existing experimental or theoretical results.

Comment on Black's (1993) article, "comparing genuine and simulated suicide notes: a new perspective".

PubMed

Diamond, G M; More, D L; Hawkins, A G; Soucar, E

1995-02-01

The recent article by Stephen T. Black (1993) comparing genuine suicide notes with simulated notes is examined here. This article corrected a sampling error made in the original study by E. S. Shneidman and N. Farberow (1957), but Black's design suffers from theoretical and methodological problems that render it uninterpretable: First, no theoretical background is elaborated, and no hypotheses are offered. Second, no constructs are operationalized, and no predictions are tested. In the present article, the operational design is critiqued, and then it is suggested that the study of suicide notes in this fashion should cease.

Experimental and Theoretical Studies of Axisymmetric Free Jets

NASA Technical Reports Server (NTRS)

Love, Eugene S.; Grigsby, Carl E.; Lee, Louise P.; Woodling, Mildred J.

1959-01-01

Some experimental and theoretical studies have been made of axisymmetric free jets exhausting from sonic and supersonic nozzles into still air and into supersonic streams with a view toward problems associated with propulsive jets and the investigation of these problems. For jets exhausting into still air, consideration is given to the effects of jet Mach number, nozzle divergence angle, and jet static pressure ratio upon jet structure, jet wavelength, and the shape and curvature of the jet boundary. Studies of the effects of the ratio of specific heats of the jets are included are observations pertaining to jet noise and jet simulation. For jets exhausting into supersonic streams, an attempt has been made to present primarily theoretical certain jet interference effects and in formulating experimental studies. The primary variables considered are jet Mach number, free stream Mach number, jet static pressure ratio, ratio of specific heats of the jet, nozzle exit angle, and boattail angle. The simulation problem and the case of a hypothetical hypersonic vehicle are examined, A few experimental observations are included.

How Does Lesson Study Improve Mathematics Instruction?

ERIC Educational Resources Information Center

Lewis, Catherine

2016-01-01

This article presents a theoretical model of lesson study's impact on instruction, through intervening impact on teachers' knowledge, beliefs and dispositions, teachers' learning community, and curriculum. It also describes four different types of lesson study in Japan, pointing out their synergies in producing a system where local teachers…

Institute of Theoretical and Experimental Physics (ITEP, Moscow) in the H1 experiment

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

Efremenko, V. I.

A group of researchers from the Institute of Theoretical and Experimental Physics (ITEP, Moscow) took part at almost all stages of the H1 experiment performed at the HERA collider (Hamburg) in order to study lepton-proton interactions at high energies. Several subdetectors of the H1 detector were developed, designed, and constructed at the ITEP industrial workshop and domestic enterprises. In particular, the ITEP staff participated in assembling and tunning the equipment, servicing the detector and the data acquisition system, and analyzing and presenting the results. Researchers from ITEP have been playing a crucial role at many stages of the experiment tomore » the present day.« less

Probing Gap Plasmons Down to Subnanometer Scales Using Collapsible Nanofingers

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

Song, Boxiang; Yao, Yuhan; Groenewald, Roelof E.

Gap plasmonic nanostructures are of great interest due to their ability to concentrate light into small volumes. Theoretical studies, considering quantum mechanical effects, have predicted the optimal spatial gap between adjacent nanoparticles to be in the subnanometer regime in order to achieve the strongest possible field enhancement. In this paper, we present a technology to fabricate gap plasmonic structures with subnanometer resolution, high reliability, and high throughput using collapsible nanofingers. This approach enables us to systematically investigate the effects of gap size and tunneling barrier height. Finally, the experimental results are consistent with previous findings as well as with amore » straightforward theoretical model that is presented here.« less

Probing Gap Plasmons Down to Subnanometer Scales Using Collapsible Nanofingers

DOE PAGES

Song, Boxiang; Yao, Yuhan; Groenewald, Roelof E.; ...

2017-06-09

Gap plasmonic nanostructures are of great interest due to their ability to concentrate light into small volumes. Theoretical studies, considering quantum mechanical effects, have predicted the optimal spatial gap between adjacent nanoparticles to be in the subnanometer regime in order to achieve the strongest possible field enhancement. In this paper, we present a technology to fabricate gap plasmonic structures with subnanometer resolution, high reliability, and high throughput using collapsible nanofingers. This approach enables us to systematically investigate the effects of gap size and tunneling barrier height. Finally, the experimental results are consistent with previous findings as well as with amore » straightforward theoretical model that is presented here.« less

The water dimer II: Theoretical investigations

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Anamika; Xantheas, Sotiris S.; Saykally, Richard J.

2018-05-01

As the archetype of aqueous hydrogen bonding, the water dimer has been extensively studied by both theory and experiment for nearly seven decades. In this article, we present a detailed chronological review of the theoretical advances made using electronic structure methods to address the structure, hydrogen bonding and vibrational spectroscopy of the water dimer, as well as the role of its potential energy surface in the development of classical force fields to describe intermolecular interactions in clusters and the condensed phases of water.

The Water Dimer II: Theoretical Investigations

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

Mukhopadhyay, Anamika; Xantheas, Sotiris S.; Saykally, Richard J.

As the archetype of aqueous hydrogen bonding, the water dimer has been extensively studied by both theory and experiment for nearly seven decades. Here in this article, we present a detailed chronological review of the theoretical advances made using electronic structure methods to address the structure, hydrogen bonding and vibrational spectroscopy of the water dimer, as well as the role of its potential energy surface in the development of classical force fields to describe intermolecular interaction in clusters and the condensed phases of water.

The Water Dimer II: Theoretical Investigations

DOE PAGES

Mukhopadhyay, Anamika; Xantheas, Sotiris S.; Saykally, Richard J.

2018-03-29

As the archetype of aqueous hydrogen bonding, the water dimer has been extensively studied by both theory and experiment for nearly seven decades. Here in this article, we present a detailed chronological review of the theoretical advances made using electronic structure methods to address the structure, hydrogen bonding and vibrational spectroscopy of the water dimer, as well as the role of its potential energy surface in the development of classical force fields to describe intermolecular interaction in clusters and the condensed phases of water.

Uncertainties on exclusive diffractive Higgs boson and jet production at the LHC

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

Dechambre, A.; CEA/IRFU/Service de physique des particules, CEA/Saclay; Kepka, O.

2011-03-01

Two theoretical descriptions of exclusive diffractive jets and Higgs production at the LHC were implemented into the FPMC generator: the Khoze, Martin, Ryskin model and the Cudell, Hernandez, Ivanov, Dechambre exclusive model. We then study the uncertainties. We compare their predictions to the CDF measurement and discuss the possibility of constraining the exclusive Higgs production at the LHC with early measurements of exclusive jets. We show that the present theoretical uncertainties can be reduced with such data by a factor of 5.

Theoretical and experimental characterization of the first hyperpolarizability

NASA Astrophysics Data System (ADS)

Perez-Moreno, Javier

We present a theoretical and experimental study of the molecular susceptibilities. The generalized Thomas-Kuhn sum rules are used to characterize the nonlinear response of organic chromophores in terms of fundamental parameters. The nonlinear optical performance of real molecules is evaluated from the calculation of the quantum limits and Hyper-Rayleigh scattering measurements. Different strategies for the enhancement of nonlinear behavior at the molecular and supramolecular level are evaluated and new paradigms for de design of more efficient nonlinear molecules are proposed.

An accurate method for solving a class of fractional Sturm-Liouville eigenvalue problems

NASA Astrophysics Data System (ADS)

Kashkari, Bothayna S. H.; Syam, Muhammed I.

2018-06-01

This article is devoted to both theoretical and numerical study of the eigenvalues of nonsingular fractional second-order Sturm-Liouville problem. In this paper, we implement a fractional-order Legendre Tau method to approximate the eigenvalues. This method transforms the Sturm-Liouville problem to a sparse nonsingular linear system which is solved using the continuation method. Theoretical results for the considered problem are provided and proved. Numerical results are presented to show the efficiency of the proposed method.

A theoretical formulation of wave-vortex interactions

NASA Technical Reports Server (NTRS)

Wu, J. Z.; Wu, J. M.

1989-01-01

A unified theoretical formulation for wave-vortex interaction, designated the '(omega, Pi) framework,' is presented. Based on the orthogonal decomposition of fluid dynamic interactions, the formulation can be used to study a variety of problems, including the interaction of a longitudinal (acoustic) wave and/or transverse (vortical) wave with a main vortex flow. Moreover, the formulation permits a unified treatment of wave-vortex interaction at various approximate levels, where the normal 'piston' process and tangential 'rubbing' process can be approximated dfferently.

Introduction to Theoretical Modelling

NASA Astrophysics Data System (ADS)

Davis, Matthew J.; Gardiner, Simon A.; Hanna, Thomas M.; Nygaard, Nicolai; Proukakis, Nick P.; Szymańska, Marzena H.

2013-02-01

We briefly overview commonly encountered theoretical notions arising in the modelling of quantum gases, intended to provide a unified background to the `language' and diverse theoretical models presented elsewhere in this book, and aimed particularly at researchers from outside the quantum gases community.

Realization of Rectangular Artificial Spin Ice and Direct Observation of High Energy Topology.

PubMed

Ribeiro, I R B; Nascimento, F S; Ferreira, S O; Moura-Melo, W A; Costa, C A R; Borme, J; Freitas, P P; Wysin, G M; de Araujo, C I L; Pereira, A R

2017-10-25

In this work, we have constructed and experimentally investigated frustrated arrays of dipoles forming two-dimensional artificial spin ices with different lattice parameters (rectangular arrays with horizontal and vertical lattice spacings denoted by a and b respectively). Arrays with three different aspect ratios γ = a/b = [Formula: see text], [Formula: see text] and [Formula: see text] are studied. Theoretical calculations of low-energy demagnetized configurations for these same parameters are also presented. Experimental data for demagnetized samples confirm most of the theoretical results. However, the highest energy topology (doubly-charged monopoles) does not emerge in our theoretical model, while they are seen in experiments for large enough γ. Our results also insinuate that the string tension connecting two magnetic monopoles in a pair vanishes in rectangular lattices with a critical ratio γ = γ c  = [Formula: see text], supporting previous theoretical predictions.

Symbolic interactionism as a theoretical perspective for multiple method research.

PubMed

Benzies, K M; Allen, M N

2001-02-01

Qualitative and quantitative research rely on different epistemological assumptions about the nature of knowledge. However, the majority of nurse researchers who use multiple method designs do not address the problem of differing theoretical perspectives. Traditionally, symbolic interactionism has been viewed as one perspective underpinning qualitative research, but it is also the basis for quantitative studies. Rooted in social psychology, symbolic interactionism has a rich intellectual heritage that spans more than a century. Underlying symbolic interactionism is the major assumption that individuals act on the basis of the meaning that things have for them. The purpose of this paper is to present symbolic interactionism as a theoretical perspective for multiple method designs with the aim of expanding the dialogue about new methodologies. Symbolic interactionism can serve as a theoretical perspective for conceptually clear and soundly implemented multiple method research that will expand the understanding of human health behaviour.

Theoretical modeling and experimental analysis of solar still integrated with evacuated tubes

NASA Astrophysics Data System (ADS)

Panchal, Hitesh; Awasthi, Anuradha

2017-06-01

In this present research work, theoretical modeling of single slope, single basin solar still integrated with evacuated tubes has been performed based on energy balance equations. Major variables like water temperature, inner glass cover temperature and distillate output has been computed based on theoretical modeling. The experimental setup has been made from locally available materials and installed at Gujarat Power Engineering and Research Institute, Mehsana, Gujarat, India (23.5880°N, 72.3693°E) with 0.04 m depth during 6 months of time interval. From the series of experiments, it is found considerable increment in average distillate output of a solar still when integrated with evacuated tubes not only during daytime but also from night time. In all experimental cases, the correlation of coefficient (r) and root mean square percentage deviation of theoretical modeling and experimental study found good agreement with 0.97 < r < 0.98 and 10.22 < e < 38.4% respectively.

Position resolution simulations for the inverted-coaxial germanium detector, SIGMA

NASA Astrophysics Data System (ADS)

Wright, J. P.; Harkness-Brennan, L. J.; Boston, A. J.; Judson, D. S.; Labiche, M.; Nolan, P. J.; Page, R. D.; Pearce, F.; Radford, D. C.; Simpson, J.; Unsworth, C.

2018-06-01

The SIGMA Germanium detector has the potential to revolutionise γ-ray spectroscopy, providing superior energy and position resolving capabilities compared with current large volume state-of-the-art Germanium detectors. The theoretical position resolution of the detector as a function of γ-ray interaction position has been studied using simulated detector signals. A study of the effects of RMS noise at various energies has been presented with the position resolution ranging from 0.33 mm FWHM at Eγ = 1 MeV, to 0.41 mm at Eγ = 150 keV. An additional investigation into the effects pulse alignment have on pulse shape analysis and in turn, position resolution has been performed. The theoretical performance of SIGMA operating in an experimental setting is presented for use as a standalone detector and as part of an ancillary system.

Dynamics of dissociative electron attachment to ammonia

DOE PAGES

Rescigno, T. N.; Trevisan, C. S.; Orel, A. E.; ...

2016-05-12

We present that ab initio theoretical studies and momentum-imaging experiments are combined to provide a consistent picture of the dynamics of dissociative electron attachment to ammonia through its 5.5- and 10.5-eV resonance channels. The present study clarifies the character and symmetry of the anion states involved and the dynamics that leads to the observed fragment-ion channels, their branching ratios, and angular distributions.

Dynamics of dissociative electron attachment to ammonia

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

Rescigno, T. N.; Trevisan, C. S.; Orel, A. E.

We present that ab initio theoretical studies and momentum-imaging experiments are combined to provide a consistent picture of the dynamics of dissociative electron attachment to ammonia through its 5.5- and 10.5-eV resonance channels. The present study clarifies the character and symmetry of the anion states involved and the dynamics that leads to the observed fragment-ion channels, their branching ratios, and angular distributions.

The role of language in learning physics

NASA Astrophysics Data System (ADS)

Brookes, David T.

Many studies in PER suggest that language poses a serious difficulty for students learning physics. These difficulties are mostly attributed to misunderstanding of specialized terminology. This terminology often assigns new meanings to everyday terms used to describe physical models and phenomena. In this dissertation I present a novel approach to analyzing of the role of language in learning physics. This approach is based on the analysis of the historical development of physics ideas, the language of modern physicists, and students' difficulties in the areas of quantum mechanics, classical mechanics, and thermodynamics. These data are analyzed using linguistic tools borrowed from cognitive linguistics and systemic functional grammar. Specifically, I combine the idea of conceptual metaphor and grammar to build a theoretical framework that accounts for: (1) the role and function that language serves for physicists when they speak and reason about physical ideas and phenomena, (2) specific features of students' reasoning and difficulties that may be related to or derived from language that students read or hear. The theoretical framework is developed using the methodology of a grounded theoretical approach. The theoretical framework allows us to make predictions about the relationship between student discourse and their conceptual and problem solving difficulties. Tests of the theoretical framework are presented in the context of "heat" in thermodynamics and "force" in dynamics. In each case the language that students use to reason about the concepts of "heat" and "force" is analyzed using the theoretical framework. The results of this analysis show that language is very important in students' learning. In particular, students are (1) using features of physicists' conceptual metaphors to reason about physical phenomena, often overextending and misapplying these features, (2) drawing cues from the grammar of physicists' speech and writing to categorize physics concepts; this categorization of physics concepts plays a key role in students' ability to solve physics problems. In summary, I present a theoretical framework that provides a possible explanation of the role that language plays in learning physics. The framework also attempts to account for how and why physicists' language influences students in the way that it does.

Study on the influence of X-ray tube spectral distribution on the analysis of bulk samples and thin films: Fundamental parameters method and theoretical coefficient algorithms

NASA Astrophysics Data System (ADS)

Sitko, Rafał

2008-11-01

Knowledge of X-ray tube spectral distribution is necessary in theoretical methods of matrix correction, i.e. in both fundamental parameter (FP) methods and theoretical influence coefficient algorithms. Thus, the influence of X-ray tube distribution on the accuracy of the analysis of thin films and bulk samples is presented. The calculations are performed using experimental X-ray tube spectra taken from the literature and theoretical X-ray tube spectra evaluated by three different algorithms proposed by Pella et al. (X-Ray Spectrom. 14 (1985) 125-135), Ebel (X-Ray Spectrom. 28 (1999) 255-266), and Finkelshtein and Pavlova (X-Ray Spectrom. 28 (1999) 27-32). In this study, Fe-Cr-Ni system is selected as an example and the calculations are performed for X-ray tubes commonly applied in X-ray fluorescence analysis (XRF), i.e., Cr, Mo, Rh and W. The influence of X-ray tube spectra on FP analysis is evaluated when quantification is performed using various types of calibration samples. FP analysis of bulk samples is performed using pure-element bulk standards and multielement bulk standards similar to the analyzed material, whereas for FP analysis of thin films, the bulk and thin pure-element standards are used. For the evaluation of the influence of X-ray tube spectra on XRF analysis performed by theoretical influence coefficient methods, two algorithms for bulk samples are selected, i.e. Claisse-Quintin (Can. Spectrosc. 12 (1967) 129-134) and COLA algorithms (G.R. Lachance, Paper Presented at the International Conference on Industrial Inorganic Elemental Analysis, Metz, France, June 3, 1981) and two algorithms (constant and linear coefficients) for thin films recently proposed by Sitko (X-Ray Spectrom. 37 (2008) 265-272).

Experimental and theoretical investigations of the kinetics and mechanism of the Cl + 4-hydroxy-4-methyl-2-pentanone reaction

NASA Astrophysics Data System (ADS)

Aslan, L.; Priya, A. Mano; Sleiman, C.; Zeineddine, M. N.; Coddeville, P.; Fittschen, C.; Ballesteros, B.; Canosa, A.; Senthilkumar, L.; El Dib, G.; Tomas, A.

2017-10-01

The reaction of 4-hydroxy-4-methyl-2-pentanone (4H4M2P) with Cl atoms was studied for the first time experimentally and theoretically. Relative kinetic measurements were carried out at room temperature and 1 bar of synthetic air/N2 in two different environmental chambers: a 300 L Teflon bag and a 16 L borosilicate glass cell. Reactants, reference compounds and products were monitored either by IR absorption or by GC-FID. Theoretical calculations were performed using the density functional theory method at BH&HLYP level of theory for twelve hydrogen abstraction pathways. The individual rate coefficients for the most favorable H-abstraction pathways were calculated by canonical variational theory using small curvature tunneling method at 298 K. An average experimental rate coefficient of (7.4 ± 0.6) × 10-11 cm3 molecule-1 s-1 was obtained at 298 K, in good agreement with the theoretical rate coefficient. The branching ratios for each reaction channel were evaluated theoretically from the individual rate coefficients of the identified channels. The H-atom abstracted on the -CH2 group appeared to be the dominant channel with a small barrier height. Formaldehyde, acetic acid, HCl, CO2 and CO were identified by IR as the major primary products. The obtained results are presented and discussed in terms of structure-reactivity relationships. A mechanism is suggested for the formation of the observed products. The atmospheric implications of the studied reaction are presented and more particularly, the lifetime of 4H4M2P towards Cl atoms is evaluated to be about 3 days.

Spectral and structural studies of the anti-cancer drug Flutamide by density functional theoretical method.

PubMed

Mariappan, G; Sundaraganesan, N

2014-01-03

A comprehensive screening of the more recent DFT theoretical approach to structural analysis is presented in this section of theoretical structural analysis. The chemical name of 2-methyl-N-[4-nitro-3-(trifluoromethyl)phenyl]-propanamide is usually called as Flutamide (In the present study it is abbreviated as FLT) and is an important and efficacious drug in the treatment of anti-cancer resistant. The molecular geometry, vibrational spectra, electronic and NMR spectral interpretation of Flutamide have been studied with the aid of density functional theory method (DFT). The vibrational assignments of the normal modes were performed on the basis of the PED calculations using the VEDA 4 program. Comparison of computational results with X-ray diffraction results of Flutamide allowed the evaluation of structure predictions and confirmed B3LYP/6-31G(d,p) as accurate for structure determination. Application of scaling factors for IR and Raman frequency predictions showed good agreement with experimental values. This is supported the assignment of the major contributors of the vibration modes of the title compound. Stability of the molecule arising from hyperconjugative interactions leading to its bioactivity, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. NMR chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. The comparison of measured FTIR, FT-Raman, and UV-Visible data to calculated values allowed assignment of major spectral features of the title molecule. Besides, Frontier molecular orbital analyze was also investigated using theoretical calculations. Copyright © 2013 Elsevier B.V. All rights reserved.

The Alkaline Hydrolysis of Sulfonate Esters: Challenges in Interpreting Experimental and Theoretical Data

PubMed Central

2013-01-01

Sulfonate ester hydrolysis has been the subject of recent debate, with experimental evidence interpreted in terms of both stepwise and concerted mechanisms. In particular, a recent study of the alkaline hydrolysis of a series of benzene arylsulfonates (Babtie et al., Org. Biomol. Chem.10, 2012, 8095) presented a nonlinear Brønsted plot, which was explained in terms of a change from a stepwise mechanism involving a pentavalent intermediate for poorer leaving groups to a fully concerted mechanism for good leaving groups and supported by a theoretical study. In the present work, we have performed a detailed computational study of the hydrolysis of these compounds and find no computational evidence for a thermodynamically stable intermediate for any of these compounds. Additionally, we have extended the experimental data to include pyridine-3-yl benzene sulfonate and its N-oxide and N-methylpyridinium derivatives. Inclusion of these compounds converts the Brønsted plot to a moderately scattered but linear correlation and gives a very good Hammett correlation. These data suggest a concerted pathway for this reaction that proceeds via an early transition state with little bond cleavage to the leaving group, highlighting the care that needs to be taken with the interpretation of experimental and especially theoretical data. PMID:24279349

Interplay between theory and experiment: computational organometallic and transition metal chemistry.

PubMed

Lin, Zhenyang

2010-05-18

Computational and theoretical chemistry provide fundamental insights into the structures, properties, and reactivities of molecules. As a result, theoretical calculations have become indispensable in various fields of chemical research and development. In this Account, we present our research in the area of computational transition metal chemistry, using examples to illustrate how theory impacts our understanding of experimental results and how close collaboration between theoreticians and experimental chemists can be mutually beneficial. We begin by examining the use of computational chemistry to elucidate the details of some unusual chemical bonds. We consider the three-center, two-electron bonding in titanocene sigma-borane complexes and the five-center, four-electron bonding in a rhodium-bismuth complex. The bonding in metallabenzene complexes is also examined. In each case, theoretical calculations provide particular insight into the electronic structure of the chemical bonds. We then give an example of how theoretical calculations aided the structural determination of a kappa(2)-N,N chelate ruthenium complex formed upon heating an intermediate benzonitrile-coordinated complex. An initial X-ray diffraction structure proposed on the basis of a reasonable mechanism appeared to fit well, with an apparently acceptable R value of 0.0478. But when DFT calculations were applied, the optimized geometry differed significantly from the experimental data. By combining experimental and theoretical outlooks, we posited a new structure. Remarkably, a re-refining of the X-ray diffraction data based on the new structure resulted in a slightly lower R value of 0.0453. We further examine the use of computational chemistry in providing new insight into C-H bond activation mechanisms and in understanding the reactivity properties of nucleophilic boryl ligands, addressing experimental difficulties with calculations and vice versa. Finally, we consider the impact of theoretical insights in three very specific experimental studies of chemical reactions, illustrating how theoretical results prompt further experimental studies: (i) diboration of aldehydes catalyzed by copper(I) boryl complexes, (ii) ruthenium-catalyzed C-H amination of arylazides, and (iii) zinc reduction of a vinylcarbyne complex. The concepts and examples presented here are intended for nonspecialists, particularly experimentalists. Together, they illustrate some of the achievements that are possible with a fruitful union of experiment and theory.

A utility-theoretic model for QALYs and willingness to pay.

PubMed

Klose, Thomas

2003-01-01

Despite the widespread use of quality-adjusted life years (QALY) in economic evaluation studies, their utility-theoretic foundation remains unclear. A model for preferences over health, money, and time is presented in this paper. Under the usual assumptions of the original QALY-model, an additive separable presentation of the utilities in different periods exists. In contrast to the usual assumption that QALY-weights do solely depend on aspects of health-related quality of life, wealth-standardized QALY-weights might vary with the wealth level in the presented extension of the original QALY-model resulting in an inconsistent measurement of QALYs. Further assumptions are presented to make the measurement of QALYs consistent with lifetime preferences over health and money. Even under these strict assumptions, QALYs and WTP (which also can be defined in this utility-theoretic model) are not equivalent preference-based measures of the effects of health technologies on an individual level. The results suggest that the individual WTP per QALY can depend on the magnitude of the QALY-gain as well as on the disease burden, when health influences the marginal utility of wealth. Further research seems to be indicated on this structural aspect of preferences over health and wealth and to quantify its impact. Copyright 2002 John Wiley & Sons, Ltd.

Conceptual Diversity, Moderators, and Theoretical Issues in Quantitative Studies of Cultural Capital Theory

ERIC Educational Resources Information Center

Tan, Cheng Yong

2017-01-01

The present study reviewed quantitative empirical studies examining the relationship between cultural capital and student achievement. Results showed that researchers had conceptualized and measured cultural capital in different ways. It is argued that the more holistic understanding of the construct beyond highbrow cultural consumption must be…

eBlack Studies: A Twenty-First-Century Challenge.

ERIC Educational Resources Information Center

Alkalimat, Abdul

2000-01-01

Calls for the transformation of black studies that moves from ideology to information. Argues that eBlack, the virtualization of the black experience, is the basis for the next stage of this academic discipline. Presents three theoretical principles of eBlack studies (cyberdemocracy, collective intelligence, and information freedom); describes…

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

NASA Astrophysics Data System (ADS)

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

2012-11-01

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

Theoretical and experimental study of AC electrical conduction mechanism in the low temperature range of p-CuIn3Se5

NASA Astrophysics Data System (ADS)

Essaleh, L.; Amhil, S.; Wasim, S. M.; Marín, G.; Choukri, E.; Hajji, L.

2018-05-01

In the present work, an attempt has been made to study theoretically and experimentally the AC electrical conduction mechanism in disordered semiconducting materials. The key parameter considered in this analysis is the frequency exponent s(ω , T) =( ∂ln(σAC(ω , T))/∂ ln(ω)T , where σAC is the AC electrical conductivity that depends on angular frequency ω and temperature T. In the theoretical part of this work, the effect of the barrier hopping energy, the polaron radius and the characteristic relaxation time is considered. The theoretical models of Quantum Mechanical Tunneling (QMT), Non overlapping Small Polaron Tunneling (NSPT), Overlapping Large Polaron Tunneling (OLPT) and Correlated Barrier Hopping (CBH) are considered to fit experimental data of σAC in p-CuIn3Se5 (p-CIS135) in the low temperature range up to 96 K. Some important parameters, as the polaron radius, the localization length and the barrier hopping energies, are estimated and their temperature and frequency dependence discussed.

Ab-Initio Calculation of the Magnetic Properties of Metal-Doped Boron-Nitrogen Nanoribbon

NASA Astrophysics Data System (ADS)

Rufinus, J.

2017-10-01

The field of spintronics has been continuously attracting researchers. Tremendous efforts have been made in the quest to find good candidates for future spintronic devices. One particular type of material called graphene is under extensive theoretical study as a feasible component for practical applications. However, pristine graphene is diamagnetic. Thus, a lot of research has been performed to modify the graphene-based structure to achieve meaningful magnetic properties. Recently, a new type of graphene-based one-dimensional material called Boron Nitrogen nanoribbon (BNNR) has been of interest, due to the theoretical predictions that this type of material shows half-metallic property. Here we present the results of the theoretical and computational study of M-doped (M = Cr, Mn) Zigzag BNNR (ZBNNR), the objective of which is to determine whether the presence of these dopants will give rise to ferromagnetism. We have found that the concentration and the atomic distance among the dopants affect the magnetic ordering of this type of material. These results provide a meaningful theoretical prediction of M-doped ZBNNR as a basic candidate of future spintronic devices.

Positron total scattering cross-sections for alkali atoms

NASA Astrophysics Data System (ADS)

Sinha, Nidhi; Singh, Suvam; Antony, Bobby

2018-01-01

Positron-impact total scattering cross-sections for Li, Na, K, Rb, Cs and Fr atoms are calculated in the energy range from 5-5000 eV employing modified spherical complex optical potential formalism. The main aim of this work is to apply this formalism to the less studied positron-target collision systems. The results are compared with previous theoretical and experimental data, wherever available. In general, the present data show overall agreement and consistency with other results. Furthermore, we have done a comparative study of the results to investigate the effect of atomic size on the cross-sections as we descend through the group in the periodic table. We have also plotted a correlation graph of the present total cross-sections with polarizability and number of target electrons. The two correlation plots confirm the credibility and consistency of the present results. Besides, this is the first theoretical attempt to report positron-impact total cross-sections of alkali atoms over such a wide energy range.

Optimal Pulse Configuration Design for Heart Stimulation. A Theoretical, Numerical and Experimental Study.

NASA Astrophysics Data System (ADS)

Hardy, Neil; Dvir, Hila; Fenton, Flavio

Existing pacemakers consider the rectangular pulse to be the optimal form of stimulation current. However, other waveforms for the use of pacemakers could save energy while still stimulating the heart. We aim to find the optimal waveform for pacemaker use, and to offer a theoretical explanation for its advantage. Since the pacemaker battery is a charge source, here we probe the stimulation current waveforms with respect to the total charge delivery. In this talk we present theoretical analysis and numerical simulations of myocyte ion-channel currents acting as an additional source of charge that adds to the external stimulating charge for stimulation purposes. Therefore, we find that as the action potential emerges, the external stimulating current can be reduced accordingly exponentially. We then performed experimental studies in rabbit and cat hearts and showed that indeed exponential truncated pulses with less total charge can still induce activation in the heart. From the experiments, we present curves showing the savings in charge as a function of exponential waveform and we calculated that the longevity of the pacemaker battery would be ten times higher for the exponential current compared to the rectangular waveforms. Thanks to Petit Undergraduate Research Scholars Program and NSF# 1413037.

Dynamical and statistical behavior of discrete combustion waves: a theoretical and numerical study.

PubMed

Bharath, Naine Tarun; Rashkovskiy, Sergey A; Tewari, Surya P; Gundawar, Manoj Kumar

2013-04-01

We present a detailed theoretical and numerical study of combustion waves in a discrete one-dimensional disordered system. The distances between neighboring reaction cells were modeled with a gamma distribution. The results show that the random structure of the microheterogeneous system plays a crucial role in the dynamical and statistical behavior of the system. This is a consequence of the nonlinear interaction of the random structure of the system with the thermal wave. An analysis of the experimental data on the combustion of a gasless system (Ti + xSi) and a wide range of thermite systems was performed in view of the developed model. We have shown that the burning rate of the powder system sensitively depends on its internal structure. The present model allows for reproducing theoretically the experimental data for a wide range of pyrotechnic mixtures. We show that Arrhenius' macrokinetics at combustion of disperse systems can take place even in the absence of Arrhenius' microkinetics; it can have a purely thermal nature and be related to their heterogeneity and to the existence of threshold temperature. It is also observed that the combustion of disperse systems always occurs in the microheterogeneous mode according to the relay-race mechanism.

Dynamical and statistical behavior of discrete combustion waves: A theoretical and numerical study

NASA Astrophysics Data System (ADS)

Bharath, Naine Tarun; Rashkovskiy, Sergey A.; Tewari, Surya P.; Gundawar, Manoj Kumar

2013-04-01

We present a detailed theoretical and numerical study of combustion waves in a discrete one-dimensional disordered system. The distances between neighboring reaction cells were modeled with a gamma distribution. The results show that the random structure of the microheterogeneous system plays a crucial role in the dynamical and statistical behavior of the system. This is a consequence of the nonlinear interaction of the random structure of the system with the thermal wave. An analysis of the experimental data on the combustion of a gasless system (Ti + xSi) and a wide range of thermite systems was performed in view of the developed model. We have shown that the burning rate of the powder system sensitively depends on its internal structure. The present model allows for reproducing theoretically the experimental data for a wide range of pyrotechnic mixtures. We show that Arrhenius’ macrokinetics at combustion of disperse systems can take place even in the absence of Arrhenius’ microkinetics; it can have a purely thermal nature and be related to their heterogeneity and to the existence of threshold temperature. It is also observed that the combustion of disperse systems always occurs in the microheterogeneous mode according to the relay-race mechanism.

Direct Imaging and First Principles Studies of Si3N4/SiO2 Interface

NASA Astrophysics Data System (ADS)

Walkosz, Weronika; Klie, Robert; Ogut, Serdar; Mikijelj, Bilijana; Pennycook, Stephen; Idrobo, Juan C.

2010-03-01

It is well known that the composition of the integranular films (IGFs) in sintered polycrystalline silicon nitride (Si3N4) ceramics controls many of their physical and mechanical properties. A considerable effort has been made to characterize these films on the atomic scale using both experimental and theoretical methods. In this talk, we present results from a combined atomic-resolution Z-contrast and annular bright field imaging, electron energy-loss spectroscopy, as well as ab initio studies of the interface between β-Si3N4 (10-10) and SiO2 intergranular film. Our results show that O replaces N at the interface between the two materials in agreement with our theoretical calculations and that N is present in the SiO2 IGF. Moreover, they indicate the presence of atomic columns completing Si3N4 open rings, which have not been observed experimentally at the recently imaged Si3N4/rare-earth oxides interfaces, but have been predicted theoretically on bare Si3N4 surfaces. The structural and electronic variations at the Si3N4/SiO2 interface will be discussed in detail, focusing in particular on bonding characteristics.

Distribution of pre-course BLS/AED manuals does not influence skill acquisition and retention in lay rescuers: a randomised study.

PubMed

Papadimitriou, Lila; Xanthos, Theodoros; Bassiakou, Eleni; Stroumpoulis, Kostantinos; Barouxis, Dimitrios; Iacovidou, Nicolleta

2010-03-01

The present study aims to investigate whether the distribution of the Basic Life Support and Automated External Defibrillation (BLS/AED) manual, 4 weeks prior to the course, has an effect on skill acquisition, theoretical knowledge and skill retention, compared with courses where manuals were not distributed. A total of 303 laypeople were included in the present study. The courses were randomised with sealed envelopes in 12 courses, where manuals were distributed to participants (group A) and in 12 courses, where manuals were not distributed to participants (group B). The participants were formally evaluated at the end of the course, and at 1, 3 and 6 months after each course. The evaluation procedure was the same at all time intervals and consisted of two distinct parts: a written test and a simulated cardiac arrest scenario. No significant difference was observed between the two groups in skill acquisition at the time of initial training. Furthermore, there was no significant difference between the groups in performing BLS/AED skills at 1, 3 and 6 months after initial training. Theoretical knowledge in either group at the specified time intervals did not exhibit any significant difference. Significant deterioration of skills was observed in both groups between initial training and at 1 month after the course, as well as between the first and third month after the course. The present study shows that distribution of BLS/AED manuals 1 month prior to the course has no effect on theoretical knowledge, skill acquisition and skill retention in laypeople. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Theorising the Relationship between Older People and Their Immediate Social Living Environment

ERIC Educational Resources Information Center

Buffel, Tine; Verte, Dominique; De Donder, Liesbeth; De Witte, Nico; Dury, Sarah; Vanwing, Tom; Bolsenbroek, Anouk

2012-01-01

This article presents a theoretical framework for exploring the dynamics between older people and their immediate social living environment. After introducing a gerontological perspective that goes beyond "microfication," a literature review presents findings from studies that have explored the role of place and locality for older people. Next,…

An Investigation of Two Ways of Presenting Vocabulary

ERIC Educational Resources Information Center

Papathanasiou, Evagelia

2009-01-01

The use of semantic links or networks in L2 vocabulary acquisition has been a popular subject for numerous studies. On one hand, there is a strong theoretical background stating that presenting words in related fashion facilitates the learning of L2 vocabulary. On the other hand, research evidence indicates that semantically related vocabulary…

The Construction of Social Class in Social Work Education: A Study of Introductory Textbooks

ERIC Educational Resources Information Center

Strier, Roni; Feldman, Guy; Shdaimah, Corey

2012-01-01

Social work introductory textbooks reflect myriad practical interests, pedagogical concerns, and theoretical considerations. However, they also present students with accepted views, dominant perspectives, and main discourses of knowledge. In light of this centrality, the present article examines the representation of the concept of "social class"…

Trends in Distance Education: A Content Analysis of Master's Thesis

ERIC Educational Resources Information Center

Durak, Gürhan; Çankaya, Serkan; Yunkul, Eyup; Urfa, Mehmet; Toprakliklioglu, Kivanç; Arda, Yagmur; Inam, Nazmiye

2017-01-01

The present study aimed at presenting the results of content analysis on Master's Theses carried out in the field of distance education at higher education level in Turkey between 1986 and 2015. A total of 285 Master's Theses were examined to determine the key words, academic disciplines, research areas, theoretical frameworks, research designs…

In the Rearview Mirror: Social Skill Development in Deaf Youth, 1990-2015

ERIC Educational Resources Information Center

Cawthon, Stephanie W.; Fink, Bentley; Schoffstall, Sarah; Wendel, Erica

2018-01-01

Social skills are a vehicle by which individuals negotiate important relationships. The present article presents historical data on how social skills in deaf students were conceptualized and studied empirically during the period 1990-2015. Using a structured literature review approach, the researchers coded 266 articles for theoretical frameworks…

Modeling sound transmission through the pulmonary system and chest with application to diagnosis of a collapsed lung

NASA Astrophysics Data System (ADS)

Royston, T. J.; Zhang, X.; Mansy, H. A.; Sandler, R. H.

2002-04-01

A theoretical and experimental study was undertaken to examine the feasibility of using audible-frequency vibro-acoustic waves for diagnosis of pneumothorax, a collapsed lung. The hypothesis was that the acoustic response of the chest to external excitation would change with this condition. In experimental canine studies, external acoustic energy was introduced into the trachea via an endotracheal tube. For the control (nonpneumothorax) state, it is hypothesized that sound waves primarily travel through the airways, couple to the lung parenchyma, and then are transmitted directly to the chest wall. In contradistinction, when a pneumothorax is present the intervening air presents an added barrier to efficient acoustic energy transfer. Theoretical models of sound transmission through the pulmonary system and chest region to the chest wall surface are developed to more clearly understand the mechanisms of intensity loss when a pneumothorax is present, relative to a baseline case. These models predict significant decreases in acoustic transmission strength when a pneumothorax is present, in qualitative agreement with experimental measurements. Development of the models, their extension via finite element analysis, and comparisons with experimental canine studies are reviewed.

PREFACE: 1st International Workshop on Theoretical and Computational Physics: Condensed Matter, Soft Matter and Materials Physics & 38th National Conference on Theoretical Physics

NASA Astrophysics Data System (ADS)

2014-09-01

This volume contains selected papers presented at the 38th National Conference on Theoretical Physics (NCTP-38) and the 1st International Workshop on Theoretical and Computational Physics: Condensed Matter, Soft Matter and Materials Physics (IWTCP-1). Both the conference and the workshop were held from 29 July to 1 August 2013 in Pullman hotel, Da Nang, Vietnam. The IWTCP-1 was a new activity of the Vietnamese Theoretical Physics Society (VTPS) organized in association with the 38th National Conference on Theoretical Physics (NCTP-38), the most well-known annual scientific forum dedicated to the dissemination of the latest development in the field of theoretical physics within the country. The IWTCP-1 was also an External Activity of the Asia Pacific Center for Theoretical Physics (APCTP). The overriding goal of the IWTCP is to provide an international forum for scientists and engineers from academia to share ideas, problems and solution relating to the recent advances in theoretical physics as well as in computational physics. The main IWTCP motivation is to foster scientific exchanges between the Vietnamese theoretical and computational physics community and world-wide scientists as well as to promote high-standard level of research and education activities for young physicists in the country. About 110 participants coming from 10 countries participated in the conference and the workshop. 4 invited talks, 18 oral contributions and 46 posters were presented at the conference. In the workshop we had one keynote lecture and 9 invited talks presented by international experts in the fields of theoretical and computational physics, together with 14 oral and 33 poster contributions. The proceedings were edited by Nguyen Tri Lan, Trinh Xuan Hoang, and Nguyen Ai Viet. We would like to thank all invited speakers, participants and sponsors for making the conference and the workshop successful. Nguyen Ai Viet Chair of NCTP-38 and IWTCP-1

Theoretical Treatment of Ion Transfers in Two Polarizable Interface Systems When the Analyte Has Access to Both Interfaces.

PubMed

Olmos, José Manuel; Molina, Ángela; Laborda, Eduardo; Millán-Barrios, Enrique; Ortuño, Joaquín Ángel

2018-02-06

A new theory is presented to tackle the study of transfer processes of hydrophilic ions in two polarizable interface systems when the analyte is initially present in both aqueous phases. The treatment is applied to macrointerfaces (linear diffusion) and microholes (highly convergent diffusion), obtaining analytical equations for the current response in any voltammetric technique. The novel equations predict two signals in the current-potential curves that are symmetric when the compositions of the aqueous phases are identical while asymmetries appear otherwise. The theoretical results show good agreement with the experimental behavior of the "double transfer voltammograms" reported by Dryfe et al. in cyclic voltammetry (CV) ( Anal. Chem. 2014 , 86 , 435 - 442 ) as well as with cyclic square wave voltammetry (cSWV) experiments performed in the current work. The theoretical treatment is also extended to the situation where the target ion is lipophilic and initially present in the organic phase. The theory predicts an opposite effect of the lipophilicity of the ion on the shape of the voltammograms, which is validated experimentally via both CV and cSWV. For the above two cases, simple and manageable expressions and diagnosis criteria are derived for the qualitative and quantitative study of ion lipophilicity. The ion-transfer potentials can be easily quantified from the separation between the two signals making use of explicit analytical equations.

Ecological Research Division Theoretical Ecology Program. [Contains abstracts

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

Not Available

1990-10-01

This report presents the goals of the Theoretical Ecology Program and abstracts of research in progress. Abstracts cover both theoretical research that began as part of the terrestrial ecology core program and new projects funded by the theoretical program begun in 1988. Projects have been clustered into four major categories: Ecosystem dynamics; landscape/scaling dynamics; population dynamics; and experiment/sample design.

Drawing Analogies between Logic Programming and Natural Language Argumentation Texts to Scaffold Learners' Understanding

ERIC Educational Resources Information Center

Ragonis, Noa; Shilo, Gila

2014-01-01

The paper presents a theoretical investigational study of the potential advantages that secondary school learners may gain from learning two different subjects, namely, logic programming within computer science studies and argumentation texts within linguistics studies. The study suggests drawing an analogy between the two subjects since they both…

Effects of Chronotypes on Students' Choice, Participation, and Performance in Online Learning

ERIC Educational Resources Information Center

Luo, Yi; Pan, Rui; Choi, Jea H.; Strobel, Johannes

2018-01-01

Introducing a new theoretical framework of chronotypes (inner biological clock), this article presents a study examining students' choices, participation, and performance in two discussion-heavy online history courses. The study comprised two major parts: a repetition study and an exploratory study. The survey adopted in the repetition study…

Statistical Learning and Language: An Individual Differences Study

ERIC Educational Resources Information Center

Misyak, Jennifer B.; Christiansen, Morten H.

2012-01-01

Although statistical learning and language have been assumed to be intertwined, this theoretical presupposition has rarely been tested empirically. The present study investigates the relationship between statistical learning and language using a within-subject design embedded in an individual-differences framework. Participants were administered…

Protein Engineering: Case Studies of Commercialized Engineered Products

ERIC Educational Resources Information Center

Walsh, Gary

2007-01-01

Programs in biochemistry invariably encompass the principles of protein engineering. Students often display increased understanding and enthusiasm when theoretical concepts are underpinned by practical example. Herein are presented five case studies, each focusing upon a commercial protein product engineered to enhance its application-relevant…

Escaping the Tyranny of Belief

ERIC Educational Resources Information Center

Wiswell, Albert K.; Wells, C. Leanne

2004-01-01

This study describes an action research case study through which the dynamics of identifying and changing strongly held assumptions illustrate the differences between experiences that serve to strengthen beliefs from those that lead to learning. Theoretical considerations are presented linking cognitive schema, action science, attribution theory,…

Towards clarification of convergent concepts: sense of coherence, will to meaning, locus of control, learned helplessness and hardiness.

PubMed

Sullivan, G C

1993-11-01

The multidisciplinary field of stress and stress-related health outcomes has generated theoretical and practical knowledge which is of interest to nurses. Theoretical developments which have assumed a prominent role in the study of stress, health and coping include the identification of various 'stress buffers' several of which bear a strong conceptual resemblance to one another. Antonovsky has developed a Salutogenic Model of stress and resistance, which is presented in this paper. The model's central concept, the sense of coherence, is described and analysed. The sense of coherence, with its three components (meaningfulness, comprehensibility and manageability), is then compared and contrasted with similar concepts. The convergent theoretical notions which are distinguished from Antonovsky's coherence are: will to meaning, locus of control, learned helplessness and hardiness. It is hoped that this analysis will provide greater conceptual clarity for nurses who study and use these concepts in education, practice or research.

The pressure distribution for biharmonic transmitting array: theoretical study

NASA Astrophysics Data System (ADS)

Baranowska, A.

2005-03-01

The aim of the paper is theoretical analysis of the finite amplitude waves interaction problem for the biharmonic transmitting array. We assume that the array consists of 16 circular pistons of the same dimensions that regrouped in two sections. Two different arrangements of radiating elements were considered. In this situation the radiating surface is non-continuous without axial symmetry. The mathematical model was built on the basis of the Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation. To solve the problem the finite-difference method was applied. On-axis pressure amplitude for different frequency waves as a function of distance from the source, transverse pressure distribution of these waves at fixed distances from the source and pressure amplitude distribution for them at fixed planes were examined. Especially changes of normalized pressure amplitude for difference frequency were studied. The paper presents mathematical model and some results of theoretical investigations obtained for different values of source parameters.

Computational study of the interplay between intermolecular interactions and CO2 orientations in type I hydrates.

PubMed

Pérez-Rodríguez, M; Vidal-Vidal, A; Míguez, J M; Blas, F J; Torré, J-P; Piñeiro, M M

2017-01-25

Carbon dioxide (CO 2 ) molecules show a rich orientation landscape when they are enclathrated in type I hydrates. Previous studies have described experimentally their preferential orientations, and some theoretical works have explained, but only partially, these experimental results. In the present paper, we use classical molecular dynamics and electronic density functional theory to advance in the theoretical description of CO 2 orientations within type I hydrates. Our results are fully compatible with those previously reported, both theoretical and experimental, the geometric shape of the cavities in hydrate being, and therefore, the steric constraints, responsible for some (but not all) preferential angles. In addition, our calculations also show that guest-guest interactions in neighbouring cages are a key factor to explain the remaining experimental angles. Besides the implication concerning equation of state hydrate modeling approximations, the conclusion is that these guest-guest interactions should not be neglected, contrary to the usual practice.

Structural studies of homoisoflavonoids: NMR spectroscopy, X-ray diffraction, and theoretical calculations

NASA Astrophysics Data System (ADS)

Sievänen, Elina; Toušek, Jaromír; Lunerová, Kamila; Marek, Jaromír; Jankovská, Dagmar; Dvorská, Margita; Marek, Radek

2010-08-01

In this article we present a detailed structural investigation for five homoisoflavonoids, molecules important from the pharmacological point of view. For studying the electron distribution as well as its influence on the physicochemical properties, NMR spectroscopy, X-ray diffraction, and theoretical calculations have been used. Nuclear magnetic shieldings obtained by using DFT calculations for optimized molecular geometries are correlated with the experimentally determined chemical shifts. The theoretical data are well in agreement with the experimental values. The single crystal X-ray structures of homoisoflavonoid derivatives 1, 3, and 4 have been solved. The molecular geometries and crystal packing determined by X-ray diffraction are used for characterizing the intermolecular interactions. Electron distribution is crucial for the stability of radicals and hence the antioxidant efficiency of flavonoid structures. The hydrogen bonding governs the formation of complexes of homoisoflavonoids with biological targets.

Experimental and theoretical studies of near-ground acoustic radiation propagation in the atmosphere

NASA Astrophysics Data System (ADS)

Belov, Vladimir V.; Burkatovskaya, Yuliya B.; Krasnenko, Nikolai P.; Rakov, Aleksandr S.; Rakov, Denis S.; Shamanaeva, Liudmila G.

2017-11-01

Results of experimental and theoretical studies of the process of near-ground propagation of monochromatic acoustic radiation on atmospheric paths from a source to a receiver taking into account the contribution of multiple scattering on fluctuations of atmospheric temperature and wind velocity, refraction of sound on the wind velocity and temperature gradients, and its reflection by the underlying surface for different models of the atmosphere depending the sound frequency, coefficient of reflection from the underlying surface, propagation distance, and source and receiver altitudes are presented. Calculations were performed by the Monte Carlo method using the local estimation algorithm by the computer program developed by the authors. Results of experimental investigations under controllable conditions are compared with theoretical estimates and results of analytical calculations for the Delany-Bazley impedance model. Satisfactory agreement of the data obtained confirms the correctness of the suggested computer program.

The Fulde–Ferrell–Larkin–Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review

NASA Astrophysics Data System (ADS)

Kinnunen, Jami J.; Baarsma, Jildou E.; Martikainen, Jani-Petri; Törmä, Päivi

2018-04-01

We review the concepts and the present state of theoretical studies of spin-imbalanced superfluidity, in particular the elusive Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state, in the context of ultracold quantum gases. The comprehensive presentation of the theoretical basis for the FFLO state that we provide is useful also for research on the interplay between magnetism and superconductivity in other physical systems. We focus on settings that have been predicted to be favourable for the FFLO state, such as optical lattices in various dimensions and spin–orbit coupled systems. These are also the most likely systems for near-future experimental observation of the FFLO state. Theoretical bounds, such as Bloch’s and Luttinger’s theorems, and experimentally important limitations, such as finite-size effects and trapping potentials, are considered. In addition, we provide a comprehensive review of the various ideas presented for the observation of the FFLO state. We conclude our review with an analysis of the open questions related to the FFLO state, such as its stability, superfluid density, collective modes and extending the FFLO superfluid concept to new types of lattice systems.

Shifting attention from objective risk factors to patients' self-assessed health resources: a clinical model for general practice.

PubMed

Hollnagel, H; Malterud, K

1995-12-01

The study was designed to present and apply theoretical and empirical knowledge for the construction of a clinical model intended to shift the attention of the general practitioner from objective risk factors to self-assessed health resources in male and female patients. Review, discussion and analysis of selected theoretical models about personal health resources involving assessing existing theories according to their emphasis concerning self-assessed vs. doctor-assessed health resources, specific health resources vs. life and coping in general, abstract vs. clinically applicable theory, gender perspective explicitly included or not. Relevant theoretical models on health and coping (salutogenesis, coping and social support, control/demand, locus of control, health belief model, quality of life), and the perspective of the underprivileged Other (critical theory, feminist standpoint theory, the patient-centred clinical method) were presented and assessed. Components from Antonovsky's salutogenetic perspective and McWhinney's patient-centred clinical method, supported by gender perspectives, were integrated to a clinical model which is presented. General practitioners are recommended to shift their attention from objective risk factors to self-assessed health resources by means of the clinical model. The relevance and feasibility of the model should be explored in empirical research.

A framework for biodynamic feedthrough analysis--part I: theoretical foundations.

PubMed

Venrooij, Joost; van Paassen, Marinus M; Mulder, Mark; Abbink, David A; Mulder, Max; van der Helm, Frans C T; Bulthoff, Heinrich H

2014-09-01

Biodynamic feedthrough (BDFT) is a complex phenomenon, which has been studied for several decades. However, there is little consensus on how to approach the BDFT problem in terms of definitions, nomenclature, and mathematical descriptions. In this paper, a framework for biodynamic feedthrough analysis is presented. The goal of this framework is two-fold. First, it provides some common ground between the seemingly large range of different approaches existing in the BDFT literature. Second, the framework itself allows for gaining new insights into BDFT phenomena. It will be shown how relevant signals can be obtained from measurement, how different BDFT dynamics can be derived from them, and how these different dynamics are related. Using the framework, BDFT can be dissected into several dynamical relationships, each relevant in understanding BDFT phenomena in more detail. The presentation of the BDFT framework is divided into two parts. This paper, Part I, addresses the theoretical foundations of the framework. Part II, which is also published in this issue, addresses the validation of the framework. The work is presented in two separate papers to allow for a detailed discussion of both the framework's theoretical background and its validation.

Theoretical evaluation of the vapor compression cycle with a liquid-line/suction-line heat exchanger, economizer, and ejector

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

Domanski, P.A.

1995-03-01

The report presents a theoretical analysis of three vapor compression cycles which are derived from the Rankine cycle by incorporating a liquid-line/suction-line heat exchanger, economizer, or ejector. These addendums to the basic cycle reduce throttling losses using different principles, and they require different mechanical hardware of different complexity and cost. The theoretical merits of the three modified cycles were evaluated in relation to the reversed Carnot and Rankine cycle. Thirty-eight fluids were included in the study using the Carnahan-Starling-DeSantis equation of state. In general, the benefit of these addendums increases with the amount of the throttling losses realized by themore » refrigerant in the Rankine cycle.« less

"Hands on" in bioengineering.

PubMed

Bastos, Teodiano F; Muller, Sandra M T

2010-01-01

Several students of Bioengineering complain about the excess of theoretical classes and the difficulty to assimilate the subject taught. This article presents a strategy to mix theory and practice when teaching, thus motivating students to engage in their studies.

A New Design for Survey Feedback

ERIC Educational Resources Information Center

Alderfer, Clayton P.; Holbrook, John

1973-01-01

Presents a theoretical discussion analyzing and explaining the use of group methods in feeding back diagnostic data to organizations, illustrating a new peer group--intergroup model with a study of senior officers at a bank. (Author/JM)

Modeling Kelvin Wave Cascades in Superfluid Helium

NASA Astrophysics Data System (ADS)

Boffetta, G.; Celani, A.; Dezzani, D.; Laurie, J.; Nazarenko, S.

2009-09-01

We study two different types of simplified models for Kelvin wave turbulence on quantized vortex lines in superfluids near zero temperature. Our first model is obtained from a truncated expansion of the Local Induction Approximation (Truncated-LIA) and it is shown to possess the same scalings and the essential behaviour as the full Biot-Savart model, being much simpler than the later and, therefore, more amenable to theoretical and numerical investigations. The Truncated-LIA model supports six-wave interactions and dual cascades, which are clearly demonstrated via the direct numerical simulation of this model in the present paper. In particular, our simulations confirm presence of the weak turbulence regime and the theoretically predicted spectra for the direct energy cascade and the inverse wave action cascade. The second type of model we study, the Differential Approximation Model (DAM), takes a further drastic simplification by assuming locality of interactions in k-space via using a differential closure that preserves the main scalings of the Kelvin wave dynamics. DAMs are even more amenable to study and they form a useful tool by providing simple analytical solutions in the cases when extra physical effects are present, e.g. forcing by reconnections, friction dissipation and phonon radiation. We study these models numerically and test their theoretical predictions, in particular the formation of the stationary spectra, and closeness of numerics for the higher-order DAM to the analytical predictions for the lower-order DAM.

Zeeman perturbed nuclear quadrupole spin echo envelope modulations for spin 3/2 nuclei in polycrystalline specimens

NASA Astrophysics Data System (ADS)

Ramachandran, R.; Narasimhan, P. T.

The results of theoretical and experimental studies of Zeeman-perturbed nuclear quadrupole spin echo envelope modulations (ZSEEM) for spin 3/2 nuclei in polycrystalline specimens are presented. The response of the Zeeman-perturbed spin ensemble to resonant two pulse excitations has been calculated using the density matrix formalism. The theoretical calculation assumes a parallel orientation of the external r.f. and static Zeeman fields and an arbitrary orientation of these fields to the principal axes system of the electric field gradient. A numerical powder averaging procedure has been adopted to simulate the response of the polycrystalline specimens. Using a coherent pulsed nuclear quadrupole resonance spectrometer the ZSEEM patterns of the 35Cl nuclei have been recorded in polycrystalline specimens of potassium chlorate, barium chlorate, mercuric chloride (two sites) and antimony trichloride (two sites) using the π/2-τ-π/2 sequence. The theoretical and experimental ZSEEM patterns have been compared. In the case of mercuric chloride, the experimental 35Cl ZSEEM patterns are found to be nearly identical for the two sites and correspond to a near-zero value of the asymmetry parameter, η, of the electric field gradient tensor. The difference in the η values for the two 35Cl sites (η ˜0·06 and η˜0·16) in antimony trichloride is clearly reflected in the experimental and theoretical ZSEEM patterns. The present study indicates the feasibility of evaluating η for spin 3/2 nuclei in polycrystalline specimens from ZSEEM investigations.

PREFACE: The International Workshop on Positron Studies of Defects 2014

NASA Astrophysics Data System (ADS)

Sugita, Kazuki; Shirai, Yasuharu

2016-01-01

The International Workshop on Positron Studies of Defects 2014 (PSD-14) was held in Kyoto, Japan from 14-19 September, 2014. The PSD Workshop brought together positron scientists interested in studying defects to an international platform for presenting and discussing recent results and achievements, including new experimental and theoretical methods in the field. The workshop topics can be characterized as follows: • Positron studies of defects in semiconductors and oxides • Positron studies of defects in metals • New experimental methods and equipment • Theoretical calculations and simulations of momentum distributions, positron lifetimes and other characteristics for defects • Positron studies of defects in combination with complementary methods • Positron beam studies of defects at surfaces, interfaces, in sub-surface regions and thin films • Nanostructures and amorphous materials

The study of theoretical and experimental feasibilities of the rocket fuel components ignition by laser radiation

NASA Astrophysics Data System (ADS)

Belyaev, Vadim S.; Guterman, Vitaly Y.; Ivanov, Anatoly V.

2004-06-01

The report presents the theoretical and experimental results obtained during the first year of the ISTC project No. 1926. The energy and temporal characteristics of the laser radiation necessary to ignite the working components mixture in a rocket engine combustion chamber have been predicted. Two approaches have been studied: the optical gas fuel laser-induced breakdown; the laser-initiated plasma torch on target surface. The possibilities and conditions of the rocket fuel components ignition by a laser beam in the differently designed combustion chambers have been estimated and studied. The comparative analysis shows that both the optical spark and light focusing on target techniques can ignite the mixture.

Theoretical studies of Pt-Ti nanoparticles for potential use as PEMFC electrocatalysts.

PubMed

Jennings, Paul C; Pollet, Bruno G; Johnston, Roy L

2012-03-07

A theoretical investigation is presented of alloying platinum with titanium to form binary Pt-Ti nanoalloys as an alternative to the expensive pure platinum catalysts commonly used for Proton Exchange Membrane Fuel Cell cathode electrocatalysts. Density Functional Theory calculations are performed to investigate compositional effects on structural properties as well as Oxygen Reduction Reaction kinetics and poisoning effects. High symmetry A(32)-B(6) clusters are studied to investigate structural properties. From these structures binding energies of hydroxyl and carbon monoxide are studied on a range of sites on the surface of the clusters. Promising results are obtained suggesting that the bimetallic Pt-Ti nanoalloys may exhibit enhanced properties compared to pure platinum catalysts.

Theoretical Calculations for Electron Impact Ionization of Atoms and Molecules

NASA Astrophysics Data System (ADS)

Amami, Sadek Mohamed Fituri

In the last twenty years, significant progress has been made for the theoretical treatment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for ionization of hydrogen and helium. However, agreement between experiment and theory is not nearly as good for ionization of larger atoms and molecules. In the first part of this dissertation, different theoretical approaches will be employed to study the triply differential cross section (TDCS) for low and intermediate energy electron-impact ionization of Neon and Argon for different orbital states. There is a very recent interest in studying ionization of Laser aligned atoms in order to get a better understanding about electron impact ionization of molecules. In the next part of this dissertation, results will be presented for electron-impact ionization of three laser aligned atoms, Mg, Ca, and Na. The comparison between the theory and experiment showed that our three body distorted wave (3DW) model gave excellent agreement with experiment in the scattering plane but very poor agreement perpendicular to the scattering plane. An explanation for this poor agreement out of the scattering plane has been provided by comparing our theoretical results with those of the time depended close coupling (TDCC) model and this explanation is also provided in this dissertation. Recently, significant attention has been directed towards obtaining a better under-standing of electron-impact ionization of molecules which are significantly more challenging than atoms. In the last part of this dissertation, results will be presented for electron-impact ionization of three different molecules (N2 , H2O, and CH4) which have been studied comprehensively using different theoretical approximations for different types of geometries. The published papers in section two contain a detailed analysis and discussion for each of these topics.

Optimality conditions for the numerical solution of optimization problems with PDE constraints :

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

Aguilo Valentin, Miguel Alejandro; Ridzal, Denis

2014-03-01

A theoretical framework for the numerical solution of partial di erential equation (PDE) constrained optimization problems is presented in this report. This theoretical framework embodies the fundamental infrastructure required to e ciently implement and solve this class of problems. Detail derivations of the optimality conditions required to accurately solve several parameter identi cation and optimal control problems are also provided in this report. This will allow the reader to further understand how the theoretical abstraction presented in this report translates to the application.

Polarimetric scattering behavior of materials at terahertz frequencies

NASA Astrophysics Data System (ADS)

DiGiovanni, David Anthony

Terahertz spectroscopic techniques have long been used to characterize the electromagnetic behavior of materials for use in radar, astronomy, and remote sensing applications. Spectroscopic information is valuable, but additional information about materials is present in the polarization of the scattered radiation. This thesis has investigated the polarimetric scattering behavior of various rough dielectric and metallic materials from 100 GHz to 1.55 THz. Common building materials and terrain, such as sand, gravel, soil, concrete, and roofing shingles, were studied. In order to obtain a better understanding of basic rough surface scattering phenomenology in this region of the spectrum, roughened metal and plastic samples were studied as well. The scattering behavior of these materials was studied as a function of incident angle, roughness, frequency, and polarization. Theoretical scattering models were used to compare measured results to theoretical predictions. Good agreement was observed between scattering measurements and theoretical predictions based on the small perturbation theory for the roughened metal surfaces. However, a substantial disagreement was observed for the rough dielectric surfaces and is discussed.

Experimental and Computational Studies of Cortical Neural Network Properties Through Signal Processing

NASA Astrophysics Data System (ADS)

Clawson, Wesley Patrick

Previous studies, both theoretical and experimental, of network level dynamics in the cerebral cortex show evidence for a statistical phenomenon called criticality; a phenomenon originally studied in the context of phase transitions in physical systems and that is associated with favorable information processing in the context of the brain. The focus of this thesis is to expand upon past results with new experimentation and modeling to show a relationship between criticality and the ability to detect and discriminate sensory input. A line of theoretical work predicts maximal sensory discrimination as a functional benefit of criticality, which can then be characterized using mutual information between sensory input, visual stimulus, and neural response,. The primary finding of our experiments in the visual cortex in turtles and neuronal network modeling confirms this theoretical prediction. We show that sensory discrimination is maximized when visual cortex operates near criticality. In addition to presenting this primary finding in detail, this thesis will also address our preliminary results on change-point-detection in experimentally measured cortical dynamics.

Theoretical Studies of the Extra-terrestrial Chemistry of Biogenic Elements and Compounds

NASA Technical Reports Server (NTRS)

Woon, David E.

2003-01-01

Results are presented on the following:(A) Ab initio quantum chemical studies of reactions in astrophysical ices.Theoretical electronic structure calculations were used to investigate reactions between formaldehyde (H2CO) and both hydrogen cyanide (HCN) and isocyanide (HNC) in search of other favorable reactions such as ammonia-formaldehyde addition, which was found in a recent theoretical study to be strongly enhanced when it occurs within cold ices.The present study examines further reactions between this product and H2CO in ices.(B) Heterogeneous hydrogenation of CO and H2CO on icy grain mantles.Formaldehyde (H2CO) and methanol (CH30H) are thought to be produced in the interstellar medium by the successive hydrogenation of carbon monoxide (CO) on grain surfaces. In the gas phase, the steps in which H adds to CO and H2CO possess modest barriers and are too inefficient to account for the observed abundances. Recent laboratory work has confirmed that formaldehyde and methanol are formed when H atoms are deposited on CO ice at 12 K. The present study employed ab initio quantum chemical calculations to investigate the impact of water ice on the sequential hydrogenation of CO.(C) Ice-bound condensed-phase reactions involving formic acid (HCOOH), methylenimine (CH2NH), hydrogen cyanide (HCN), hydrogen isocyanide (HNC), and ammonia ( 3) were investigated in order to characterize possible pathways to larger organic species that are efficient at the cold temperatures prevalent in cometary nuclei and the interstellar medium. (D) Pathways to glycine and other amino acids in ultraviolet-irradiated ices determined via quantum chemical modeling.(E) Photoionization in ultraviolet processing of astrophysical ice analogs at cryogenic temperatures.

Investigating Addiction in the Changing Universe

PubMed Central

Dastoury, Mojgan; Aminaee, Tayebe; Ghaumi, Raheleh

2014-01-01

The process of globalization as the most significant characteristic of modern era is facilitated by several factors including Information Technology, the industry of production and distribution of information, the flow of goods, services, human beings, capitals, information and etc. This phenomenon, along with the complex and various identities and life styles created by the national and transnational determinants, has widely changed the nature of social phenomena, including addition. The present study aims to investigate the contribution of sociological studies in the field of addiction during 2001 to 2011 in Iran. This is done through performing content analysis on 41 peer reviewed papers. The selected samples were surveyed and compared according to theoretical frameworks and the social groups under study. The results showed that the analyzed papers extensively overlooked the process of contemporary social changes in Iran which could be caused either by the theoretical basis of the studies or the social groups under study. Following the theoretical views of previous decades, these papers largely considered addiction as a type of social deviation and misbehavior related to the men living in urban areas. PMID:25363096

Star-forming Galaxies as AGN Imposters? A Theoretical Investigation of the Mid-infrared Colors of AGNs and Extreme Starbursts

NASA Astrophysics Data System (ADS)

Satyapal, Shobita; Abel, Nicholas P.; Secrest, Nathan J.

2018-05-01

We conduct for the first time a theoretical investigation of the mid-infrared spectral energy distribution (SED) produced by dust heated by an active galactic nucleus (AGN) and an extreme starburst. These models employ an integrated modeling approach using photoionization and stellar population synthesis models in which both the line and emergent continuum is predicted from gas exposed to the ionizing radiation from a young starburst and an AGN. In this work, we focus on the infrared colors from the Wide-field Infrared Survey Explorer, predicting the dependence of the colors on the input radiation field, the interstellar medium conditions, the obscuring column, and the metallicity. We find that an extreme starburst can mimic an AGN in two band mid-infrared color cuts employed in the literature. However, the three-band color cuts employed in the literature require starbursts with extremely high ionization parameters or gas densities. We show that the extreme mid-infrared colors seen in some blue compact dwarf galaxies are not due to metallicity but rather a combination of high ionization parameters and high column densities. Based on our theoretical calculations, we present a theoretical mid-infrared color cut that will exclude even the most extreme starburst that we have modeled in this work. The theoretical AGN demarcation region presented here can be used to identify elusive AGN candidates for future follow-up studies with the James Webb Space Telescope. The full suite of simulated SEDs are available online.

Theoretical investigation of polarization effects in solution: Importance of solvent collective motions

NASA Astrophysics Data System (ADS)

Ishida, Tateki

2015-01-01

Recent theoretical studies on interesting topics related to polarization effects in solutions are presented. As one of interesting topics, ionic liquids (ILs) solvents are focused on. The collective dynamics of electronic polarizability through interionic dynamics and the effect of polarization in ILs, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]), are studied with molecular dynamics simulation. Also, the time-dependent polarization effect on the probe betaine dye molecule, pyridinium N-phenoxide, in water is investigated by a time-dependent reference interaction site model self-consistent field (time-dependent RISM-SCF) approach. The importance of considering polarization effects on solution systems related to solvent collective motions is shown.

A theoretical study of the spheroidal droplet evaporation in forced convection

NASA Astrophysics Data System (ADS)

Li, Jie; Zhang, Jian

2014-11-01

In many applications, the shape of a droplet may be assumed to be an oblate spheroid. A theoretical study is conducted on the evaporation of an oblate spheroidal droplet under forced convection conditions. Closed-form analytical expressions of the mass evaporation rate for an oblate spheroid are derived, in the regime of controlled mass-transfer and heat-transfer, respectively. The variation of droplet size during the evaporation process is presented in the regime of shrinking dynamic model. Comparing with the droplets having the same surface area, an increase in the aspect ratio enhances the mass evaporation rate and prolongs the burnout time.

Stability and spatial arrangement of the 2,4-dichlorophenoxyacetic acid and β-cyclodextrin inclusion compound: A theoretical study

NASA Astrophysics Data System (ADS)

Pereira, Robson A.; Anconi, Cleber P. A.; Nascimento, Clebio S.; De Almeida, Wagner B.; Dos Santos, Hélio F.

2015-07-01

The present letter reports results from a comprehensive theoretical analysis of the inclusion process involving 2,4-dichlorophenoxyacetic acid (2,4-D) and β-cyclodextrin (β-CD) for which the experimental data of formation is available. Spatial arrangement and stabilization energies were evaluated in gas phase and aqueous solution through density functional theory (DFT) and through the use of SMD implicit solvation approach. The discussed methodology was applied to predict the stability and identify the most favorable form (deprotonated or neutral) as well as the most probable spatial arrangement of the studied inclusion compound.

School Leadership and Administration: Important Concepts, Case Studies and Simulations

ERIC Educational Resources Information Center

Gorton, Richard; Alston, Judy; Snowden, Petra

2006-01-01

This text helps prospective and experienced principals, administrators, and supervisors increase their knowledge and skills through concepts, case-studies, and simulations. This book contains the following two parts and fifteen chapters. Part I presents important theoretical concepts and research findings that can improve educators'…

Theoretical studies of solar lasers and converters

NASA Technical Reports Server (NTRS)

Heinbockel, John H.

1988-01-01

The previously constructed one dimensional model for the simulated operation of an iodine laser assumed that the perfluoroalkyl iodide gas n-C3F7I was incompressible. The present study removes this simplifying assumption and considers n-C3F7I as a compressible fluid.

Plasma confinement theory and transport simulation

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

Ross, D.W.

The objectives are: (1) to advance the transport studies of tokamaks, including development and maintenance of the Magnetic Fusion Energy Database, and (2) to provide theoretical interpretation, modeling and equilibrium and stability studies for TEXT-Upgrade. Recent reports, publications, and conference presentations of the Fusion Research Center are listed.

Positron scattering from pyridine

NASA Astrophysics Data System (ADS)

Stevens, D.; Babij, T. J.; Machacek, J. R.; Buckman, S. J.; Brunger, M. J.; White, R. D.; García, G.; Blanco, F.; Ellis-Gibbings, L.; Sullivan, J. P.

2018-04-01

We present a range of cross section measurements for the low-energy scattering of positrons from pyridine, for incident positron energies of less than 20 eV, as well as the independent atom model with the screening corrected additivity rule including interference effects calculation, of positron scattering from pyridine, with dipole rotational excitations accounted for using the Born approximation. Comparisons are made between the experimental measurements and theoretical calculations. For the positronium formation cross section, we also compare with results from a recent empirical model. In general, quite good agreement is seen between the calculations and measurements although some discrepancies remain which may require further investigation. It is hoped that the present study will stimulate development of ab initio level theoretical methods to be applied to this important scattering system.

Incorporating the soil environment and microbial community into plant competition theory

PubMed Central

Ke, Po-Ju; Miki, Takeshi

2015-01-01

Plants affect microbial communities and abiotic properties of nearby soils, which in turn influence plant growth and interspecific interaction, forming a plant-soil feedback (PSF). PSF is a key determinant influencing plant population dynamics, community structure, and ecosystem functions. Despite accumulating evidence for the importance of PSF and development of specific PSF models, different models are not yet fully integrated. Here, we review the theoretical progress in understanding PSF. When first proposed, PSF was integrated with various mathematical frameworks to discuss its influence on plant competition. Recent theoretical models have advanced PSF research at different levels of ecological organizations by considering multiple species, applying spatially explicit simulations to examine how local-scale predictions apply to larger scales, and assessing the effect of PSF on plant temporal dynamics over the course of succession. We then review two foundational models for microbial- and litter-mediated PSF. We present a theoretical framework to illustrate that although the two models are typically presented separately, their behavior can be understood together by invasibility analysis. We conclude with suggestions for future directions in PSF theoretical studies, which include specifically addressing microbial diversity to integrate litter- and microbial-mediated PSF, and apply PSF to general coexistence theory through a trait-based approach. PMID:26500621

On precipitation monitoring with theoretical statistical distributions

NASA Astrophysics Data System (ADS)

Cindrić, Ksenija; Juras, Josip; Pasarić, Zoran

2018-04-01

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

Envelopes in eclipsing binary stars

NASA Technical Reports Server (NTRS)

Huang, S.

1972-01-01

Theoretical research on eclipsing binaries is presented. The specific areas of investigation are the following: (1) the relevance of envelopes to the study of the light curves of eclipsing binaries, (2) the disk envelope, and (3) the spherical envelope.

Latest Trends in German Political Socialisation Research.

ERIC Educational Resources Information Center

Claussen, Bernhard

1979-01-01

Presents an overview of the most notable among recent books on political socialization in West Germany and indicates trends among these publications in areas of research methodology, objectives, stress on empirical studies, and theoretical models. (Author/DB)

[Some insights on the influence of socioeconomic factors on migratory movements].

PubMed

Gordillo, J

1981-01-01

A theoretical approach to the study of migration in Ecuador is presented. Consideration is also given to the relationships among migration, mortality, fertility, and employment and to the policy implications of these relationships.

Curvature-Squared Cosmology In The First-Order Formalism

NASA Technical Reports Server (NTRS)

Shahid-Saless, Bahman

1993-01-01

Paper presents theoretical study of some of general-relativistic ramifications of gravitational-field energy density proportional to R - alpha R(exp 2) (where R is local scalar curvature of space-time and alpha is a constant).

A Generational Approach to Understanding Students

ERIC Educational Resources Information Center

Coomes, Michael D.; DeBard, Robert

2004-01-01

This chapter establishes the conceptual framework for understanding the Millennial generation by presenting a theoretical model of generational succession that demonstrates the value of studying how the values of one generation interact with and are influenced by others.

What are science teacher's ideas about the universe?

NASA Astrophysics Data System (ADS)

Novotný, Jan; Svobodová, Jindřiška

2017-01-01

The new cosmological discoveries over the past two decades have a great impact on physics. We have prepared a new university course The Introduction to Cosmology available for students without deeper math background. The results of research study and the cosmology lecturers' experiences in two years are presented. We have prepared a questionnaire and the case study to find out how students think about the Universe, how they can accept cosmology theoretical ideas. Then we use it for design follow-up activities that help students to improve their understanding. We have observed the students' views on the presented science concept and on the nature of scientific knowledge. We have prepared a questionnaire to find out how students can accept theoretical ideas. This survey was designed especially for future and contemporary science teachers. Then we use the obtained results for design follow-up activities that help students to improve their understanding. Finally the most frequented cosmology misconceptions are discussed.

Magnetically coupled magnet-spring oscillators

NASA Astrophysics Data System (ADS)

Donoso, G.; Ladera, C. L.; Martín, P.

2010-05-01

A system of two magnets hung from two vertical springs and oscillating in the hollows of a pair of coils connected in series is a new, interesting and useful example of coupled oscillators. The electromagnetically coupled oscillations of these oscillators are experimentally and theoretically studied. Its coupling is electromagnetic instead of mechanical, and easily adjustable by the experimenter. The coupling of this new coupled oscillator system is determined by the currents that the magnets induce in two coils connected in series, one to each magnet. It is an interesting case of mechanical oscillators with field-driven coupling, instead of mechanical coupling. Moreover, it is both a coupled and a damped oscillating system that lends itself to a detailed study and presentation of many properties and phenomena of such a system of oscillators. A set of experiments that validates the theoretical model of the oscillators is presented and discussed.

Predicting differences in the perceived relevance of crime's costs and benefits in a test of rational choice theory.

PubMed

Bouffard, Jeffrey A

2007-08-01

Previous hypothetical scenario tests of rational choice theory have presented all participants with the same set of consequences, implicitly assuming that these consequences would be relevant for each individual. Recent research demonstrates that those researcher-presented consequences do not accurately reflect those considered by study participants and that there is individual variation in the relevance of various consequences. Despite this and some theoretical propositions that such differences should exist, little empirical research has explored the possibility of predicting such variation. This study allows participants to develop their own set of relevant consequences for three hypothetical offenses and examines how several demographic and theoretical variables impact those consequences' relevance. Exploratory results suggest individual factors impact the perceived relevance of several cost and benefit types, even among a relatively homogenous sample of college students. Implications for future tests of rational choice theory, as well as policy implications are discussed.

Positron-Electron Annihilation Process in (2,2)-Difluoropropane Molecule

NASA Astrophysics Data System (ADS)

Liu, Yang; Ma, Xiao-Guang; Zhu, Ying-Hao

2016-04-01

The positron-electron annihilation process in (2,2)-difluoropropane molecule and the corresponding gamma-ray spectra are studied by quantum chemistry method. The positrophilic electrons in (2,2)-difluoropropane molecule are found for the first time. The theoretical predictions show that the outermost 2s electrons of fluoride atoms play an important role in positron-electron annihilation process of (2,2)-difiuoropropane. In the present scheme, the correlation coefficient between the theoretical gamma-ray spectra and the experiments can be 99%. The present study gives an alternative annihilation model for positron-electron pair in larger molecules. Supported by the National Natural Science Foundation of China under Grant No. 11347011 and the Natural Science Foundation Project of Shandong Province under Grant No. ZR2011AM010 and 2014 Technology Innovation Fund of Ludong University under Grant Nos. 1d151007 and ld15l016

The Community College IR Shop and Accreditation: A Case Study

ERIC Educational Resources Information Center

Johnston, George

2011-01-01

This article presents results of a study the author recently conducted on the role of traditional institutional research (IR) offices in support of accreditation activities and institutional effectiveness. The purpose of the study was to confirm or disconfirm the utility of a theoretical model developed by Brittingham, O'Brien, and Alig (2008) of…

Empirical Scientific Research and Legal Studies Research--A Missing Link

ERIC Educational Resources Information Center

Landry, Robert J., III

2016-01-01

This article begins with an overview of what is meant by empirical scientific research in the context of legal studies. With that backdrop, the argument is presented that without engaging in normative, theoretical, and doctrinal research in tandem with empirical scientific research, the role of legal studies scholarship in making meaningful…

Self-Psychology, Shame, and Adolescent Suicide: Theoretical and Practical Considerations.

ERIC Educational Resources Information Center

Shreve, Barry W.; Kunkel, Mark A.

1991-01-01

Discusses role of shame in adolescent suicidal behaviors using psychoanalytic self-psychology of Heinz Kohut as theoretical foundation. Describes shame as central component of suicidal behavior within context of adolescence. Offers theoretical explanation of adolescent suicidal behavior from self-psychology perspective. Presents suggestions for…

The Institute Papers: Towards a Recovery of Civic Idealism.

ERIC Educational Resources Information Center

Schwartz, Edward

The philosophy, strategy, and program of the Institute for the Study of Civic Values are presented in this collection of articles. Intended as a means of disseminating the institute's work and ideas to a general audience, the booklet is presented in four sections. Each section offers a theoretical article, an outline or a summary of an educational…

Collaborative Action Research in the Context of Developmental Work Research: A Methodological Approach for Science Teachers' Professional Development

ERIC Educational Resources Information Center

Piliouras, Panagiotis; Lathouris, Dimitris; Plakitsi, Katerina; Stylianou, Liana

2015-01-01

The paper refers to the theoretical establishment and brief presentation of collaborative action research with the characteristics of "developmental work research" as an effective methodological approach so that science teachers develop themselves professionally. A specific case study is presented, in which we aimed to transform the…

A Synthesis of Language Learning Strategies: Current Issues, Problems and Claims Made in Learner Strategy Research

ERIC Educational Resources Information Center

Barjesteh, Hamed; Mukundan, Jayakaran; Vaseghi, Reza

2014-01-01

The current paper presented theoretical assumptions behind language learning strategies (LLS) and an overview of methods used to identify learners' strategies, first, and then summarized what have been reported from large number of descriptive studies of strategies by language learners. Moreover, the paper tried to present the variety of…

Interdisciplinary Mathematics-Physics Approaches to Teaching the Concept of Angle in Elementary School

ERIC Educational Resources Information Center

Munier, Valerie; Merle, Helene

2009-01-01

The present study takes an interdisciplinary mathematics-physics approach to the acquisition of the concept of angle by children in Grades 3-5. This paper first presents the theoretical framework we developed, then we analyse the concept of angle and the difficulties pupils have with it. Finally, we report three experimental physics-based teaching…

New accurate theoretical line lists of 12CH4 and 13CH4 in the 0-13400 cm-1 range: Application to the modeling of methane absorption in Titan's atmosphere

NASA Astrophysics Data System (ADS)

Rey, Michaël; Nikitin, Andrei V.; Bézard, Bruno; Rannou, Pascal; Coustenis, Athena; Tyuterev, Vladimir G.

2018-03-01

The spectrum of methane is very important for the analysis and modeling of Titan's atmosphere but its insufficient knowledge in the near infrared, with the absence of reliable absorption coefficients, is an important limitation. In order to help the astronomer community for analyzing high-quality spectra, we report in the present work the first accurate theoretical methane line lists (T = 50-350 K) of 12CH4 and 13CH4 up to 13400 cm-1 ( > 0.75 μm). These lists are built from extensive variational calculations using our recent ab initio potential and dipole moment surfaces and will be freely accessible via the TheoReTS information system (http://theorets.univ-reims.fr, http://theorets.tsu.ru). Validation of these lists is presented throughout the present paper. For the sample of lines where upper energies were available from published analyses of experimental laboratory 12CH4 spectra, small empirical corrections in positions were introduced that could be useful for future high-resolution applications. We finally apply the TheoRetS line list to model Titan spectra as observed by VIMS and by DISR, respectively onboard Cassini and Huygens. These data are used to check that the TheoReTS line lists are able to model observations. We also make comparisons with other experimental or theoretical line lists. It appears that TheoRetS gives very reliable results better than ExoMol and even than HITRAN2012, except around 1.6 μm where it gives very similar results. We conclude that TheoReTS is suitable to be used for the modeling of planetary radiative transfer and photometry. A re-analysis of spectra recorded by the DISR instrument during the descent of the Huygens probe suggests that the CH4 mixing ratio decreases with altitude in Titan's stratosphere, reaching a value of ∼10-2 above the 110 km altitude.

Polarization characteristics of an altazimuth sky scanner

NASA Technical Reports Server (NTRS)

Garrison, L. M.; Blaszczak, Z.; Green, A. E. S.

1980-01-01

A theoretical description of the polarization characteristics of an altazimuth sky scanner optical system based on Mueller-Stokes calculus is presented. This computer-driven optical system was designed to perform laboratory studies of skylight and of celestial objects during day or night, and has no space limitations; however, the two parallel 45 deg tilt mirrors introduce some intrinsic polarization. Therefore, proper data interpretation requires a theoretical understanding of the polarization features of the instrument and accurate experimental determination of the Mueller-Stokes matrix elements describing the polarizing and depolarizing action of the system.

Numerical and Theoretical Considerations for the Design of the AVT-183 Diamond-Wing Experimental Investigations

NASA Technical Reports Server (NTRS)

Boelens, Okko J.; Luckring, James M.; Breitsamter, Christian; Hovelmann, Andreas; Knoth, Florian; Malloy, Donald J.; Deck, Sebatien

2015-01-01

A diamond-wing configuration has been developed to isolate and study blunt-leading edge vortex separation with both computations and experiments. The wing has been designed so that the results are relevant to a more complex Uninhabited Combat Air Vehicle concept known as SACCON. The numerical and theoretical development process for this diamond wing is presented, including a view toward planned wind tunnel experiments. This work was conducted under the NATO Science and Technology Organization, Applied Vehicle Technology panel. All information is in the public domain.

Key trends in environmental advertising across 30 years in National Geographic magazine.

PubMed

Ahern, Lee; Bortree, Denise Sevick; Smith, Alexandra Nutter

2013-05-01

This longitudinal retrospective case study describes the sponsors, ad types, frames and message factors in green advertising over three decades in National Geographic magazine, the bellwether nature publication in the USA. In addition to providing a clearer picture of the extent and nature of environmental strategic messaging over three decades, results provide empirical support for theoretical relationships between the level of green advertising and economic indicators. After providing historical and theoretical context, detailed results are presented for both overall and longitudinal analysis. Limitations and implications for future research are discussed.

Coagulation of dust grains in the plasma of an RF discharge in argon

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

Mankelevich, Yu. A.; Olevanov, M. A.; Pal', A. F.

2009-03-15

Results are presented from experimental studies of coagulation of dust grains of different sizes injected into a low-temperature plasma of an RF discharge in argon. A theoretical model describing the formation of dust clusters in a low-temperature plasma is developed and applied to interpret the results of experiments on the coagulation of dust grains having large negative charges. The grain size at which coagulation under the given plasma conditions is possible is estimated using the developed theory. The theoretical results are compared with the experimental data.

Underwater gas tornado

NASA Astrophysics Data System (ADS)

Byalko, Alexey V.

2013-07-01

We present the first experimental observation of a new hydrodynamic phenomenon, the underwater tornado. Simple measurements show that the tornado forms a vortex of the Rankine type, i.e. the rising gas rotates as a solid body and the liquid rotates with a velocity decreasing hyperbolically with the radius. We obtain the dependence of the tornado radius a on the gas stream value j theoretically: a ∼ j2/5. Processing of a set of experiments yielded the value 0.36 for the exponent in this expression. We also report the initial stages of the theoretical study of this phenomenon.

Low Temperature Kinetics of the First Steps of Water Cluster Formation

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

Bourgalais, J.; Roussel, V.; Capron, M.

2016-03-01

We present a combined experimental and theoretical low temperature kinetic study of water cluster formation. Water cluster growth takes place in low temperature (23-69 K) supersonic flows. The observed kinetics of formation of water clusters are reproduced with a kinetic model based on theoretical predictions for the first steps of clusterization. The temperature-and pressure-dependent association and dissociation rate coefficients are predicted with an ab initio transition state theory based master equation approach over a wide range of temperatures (20-100 K) and pressures (10(-6) - 10 bar).

Modeling of chemical reactions in micelle: water-mediated keto-enol interconversion as a case study.

PubMed

Marracino, Paolo; Amadei, Andrea; Apollonio, Francesca; d'Inzeo, Guglielmo; Liberti, Micaela; di Crescenzo, Antonello; Fontana, Antonella; Zappacosta, Romina; Aschi, Massimiliano

2011-06-30

The effect of a zwitterionic micelle environment on the efficiency of the keto-enol interconversion of 2-phenylacetylthiophene has been investigated by means of a joint application of experimental and theoretical/computational approaches. Results have revealed a reduction of the reaction rate constant if compared with bulk water essentially because of the different solvation conditions experienced by the reactant species, including water molecules, in the micelle environment. The slight inhibiting effect due to the application of a static electric field has also been theoretically investigated and presented.

The distribution of the scattered laser light in laser-plate-target coupling

NASA Astrophysics Data System (ADS)

Xiao-bo, Nie; Tie-qiang, Chang; Dong-xian, Lai; Shen-ye, Liu; Zhi-jian, Zheng

1997-04-01

Theoretical and experimental studies of the angular distributions of scattered laser light in laser-Au-plate-target coupling are reported. A simple model that describes three-dimensional plasmas and scattered laser light is presented. The approximate shape of critical density surface has been given and the three-dimensional laser ray tracing is applied in the model. The theoretical results of the model are consistent with the experimental data for the scattered laser light in the polar angle range of 25° to 145° from the laser beam.

Engineering Education as a Complex System

ERIC Educational Resources Information Center

Gattie, David K.; Kellam, Nadia N.; Schramski, John R.; Walther, Joachim

2011-01-01

This paper presents a theoretical basis for cultivating engineering education as a complex system that will prepare students to think critically and make decisions with regard to poorly understood, ill-structured issues. Integral to this theoretical basis is a solution space construct developed and presented as a benchmark for evaluating…

Computer program for assessing the theoretical performance of a three dimensional inlet

NASA Technical Reports Server (NTRS)

Agnone, A. M.; Kung, F.

1972-01-01

A computer program for determining the theoretical performance of a three dimensional inlet is presented. An analysis for determining the capture area, ram force, spillage force, and surface pressure force is presented, along with the necessary computer program. A sample calculation is also included.

WebQuests as Language-Learning Tools

ERIC Educational Resources Information Center

Aydin, Selami

2016-01-01

This study presents a review of the literature that examines WebQuests as tools for second-language acquisition and foreign language-learning processes to guide teachers in their teaching activities and researchers in further research on the issue. The study first introduces the theoretical background behind WebQuest use in the mentioned…

Collective and Individual Dimensions in Peer Positioning in Early Childhood Education

ERIC Educational Resources Information Center

Kultti, Anne; Odenbring, Ylva

2015-01-01

The present study will shed light on peer interaction and children's positioning in preschool. Theoretically, the study takes its point of departure from the concept of interpretive reproduction, which stresses the importance of children's collective actions and participation in cultural production and reproduction. Positioning refers to how…

Hydrodynamic studies of oxygen, neon, and magnesium novae

NASA Technical Reports Server (NTRS)

Starrfield, Sumner; Sparks, W. M.; Truran, J. W.

1987-01-01

Results are presented from recent theoretical studies that have examined the properties of nova outbursts on ONeMg white dwarfs. These outbursts are much more violent and occur much more frequently than outbursts on CO white dwarfs. Hydrodynamic simulations of both kinds of outbursts are in excellent agreement with the observations.

Philosophic Processes and the Study of Human Moving.

ERIC Educational Resources Information Center

Bressan, Elizabeth S.; Pieter, Willy

1985-01-01

A theoretical framework describing second-order philosophical processes that can be productive for human movement studies is presented. The processes of edification and theory building can clarify issues, expand viewpoints, and establish systematic ways of dealing with a phenomenon, leading to the more mature forms of dialogues and theories. (MT)

Theoretical Framework of Researcher Knowledge Development in Mathematics Education

ERIC Educational Resources Information Center

Kontorovich, Igor'

2016-01-01

The goal of this paper is to present a framework of researcher knowledge development in conducting a study in mathematics education. The key components of the framework are: knowledge germane to conducting a particular study, processes of knowledge accumulation, and catalyzing filters that influence a researcher's decision making. The components…

The Development and Validation of a Scale Measuring Teacher Autonomous Behaviour

ERIC Educational Resources Information Center

Evers, Arnoud T.; Verboon, Peter; Klaeijsen, Andrea

2017-01-01

In the current study a multi-dimensional scale that measures teacher autonomous behaviour is presented. The scale is applicable across the following educational sectors: primary education, secondary education and vocational education. Based on an elaborate literature study, four theoretically relevant dimensions of teacher autonomous behaviour…

Family Mediators of Acculturation and Adolescent Sexual Behavior among Latino Youth

ERIC Educational Resources Information Center

Guilamo-Ramos, Vincent; Bouris, Alida; Jaccard, James; Lesesne, Catherine A.; Gonzalez, Bernardo; Kalogerogiannis, Kosta

2009-01-01

The present study develops and evaluates a theoretical framework of mediators of the relationship between acculturation and adolescent sexual behavior. Four hundred Latino mother-adolescent dyads from the Bronx, New York were interviewed. The study explored the relationship between intentions to have sexual intercourse and explanatory variables…

Multinational Corporations, Democracy and Child Mortality: A Quantitative, Cross-National Analysis of Developing Countries

ERIC Educational Resources Information Center

Shandra, John M.; Nobles, Jenna E.; London, Bruce; Williamson, John B.

2005-01-01

This study presents quantitative, sociological models designed to account for cross-national variation in child mortality. We consider variables linked to five different theoretical perspectives that include the economic modernization, social modernization, political modernization, ecological-evolutionary, and dependency perspectives. The study is…

Scattering Of Nonplanar Acoustic Waves

NASA Technical Reports Server (NTRS)

Gillman, Judith M.; Farassat, F.; Myers, M. K.

1995-01-01

Report presents theoretical study of scattering of nonplanar acoustic waves by rigid bodies. Study performed as part of effort to develop means of predicting scattering, from aircraft fuselages, of noise made by rotating blades. Basic approach was to model acoustic scattering by use of boundary integral equation to solve equation by the Galerkin method.

Postsecondary Writing Studies in Hispanic Latin America: Intertextual Dynamics and Intellectual Influence

ERIC Educational Resources Information Center

Ávila-Reyes, Natalia

2017-01-01

As texts enact historically situated ways of making knowledge, intertextual analysis through citation patterns can shed some light on a community's epistemologies. The present research seeks a deeper understanding of the theoretical trends, the influences, and the emerging disciplinary configuration of the writing studies community in Latin…

Online Resources in Mathematics, Teachers' Geneses and Didactical Techniques

ERIC Educational Resources Information Center

Bueno-Ravel, Laetitia; Gueudet, Ghislaine

2009-01-01

The study we present here concerns the consequences of integrating online resources into the teaching of mathematics. We focus on the interaction between teachers and specific online resources they draw on: e-exercise bases. We propose a theoretical approach to study the associated phenomena, combining instrumental and anthropological…

Capturing Individual Uptake: Toward a Disruptive Research Methodology

ERIC Educational Resources Information Center

Bastian, Heather

2015-01-01

This article presents and illustrates a qualitative research methodology for studies of uptake. It does so by articulating a theoretical framework for qualitative investigations of uptake and detailing a research study designed to invoke and capture students' uptakes in a first-year writing classroom. The research design sought to make uptake…

Efficient field-theoretic simulation of polymer solutions

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

Villet, Michael C.; Fredrickson, Glenn H., E-mail: ghf@mrl.ucsb.edu; Department of Materials, University of California, Santa Barbara, California 93106

2014-12-14

We present several developments that facilitate the efficient field-theoretic simulation of polymers by complex Langevin sampling. A regularization scheme using finite Gaussian excluded volume interactions is used to derive a polymer solution model that appears free of ultraviolet divergences and hence is well-suited for lattice-discretized field theoretic simulation. We show that such models can exhibit ultraviolet sensitivity, a numerical pathology that dramatically increases sampling error in the continuum lattice limit, and further show that this pathology can be eliminated by appropriate model reformulation by variable transformation. We present an exponential time differencing algorithm for integrating complex Langevin equations for fieldmore » theoretic simulation, and show that the algorithm exhibits excellent accuracy and stability properties for our regularized polymer model. These developments collectively enable substantially more efficient field-theoretic simulation of polymers, and illustrate the importance of simultaneously addressing analytical and numerical pathologies when implementing such computations.« less

Coupled Rolling Motion: A Student Project in Non-Holonomic Mechanics

ERIC Educational Resources Information Center

Janova, Jitka; Musilova, Jana; Bartos, Jiri

2009-01-01

This paper presents an original undergraduate student project in theoretical mechanics: a demonstration of theory and experiment agreement inspired by a recently theoretically treated mechanical problem of coupled rolling motion of two cylinders. The problem of a mechanical system subjected to non-holonomic constraints is theoretically and…

Sound propagation in and radiation from acoustically lined flow ducts: A comparison of experiment and theory

NASA Technical Reports Server (NTRS)

Plumblee, H. E., Jr.; Dean, P. D.; Wynne, G. A.; Burrin, R. H.

1973-01-01

The results of an experimental and theoretical study of many of the fundamental details of sound propagation in hard wall and soft wall annular flow ducts are reported. The theory of sound propagation along such ducts and the theory for determining the complex radiation impedance of higher order modes of an annulus are outlined, and methods for generating acoustic duct modes are developed. The results of a detailed measurement program on propagation in rigid wall annular ducts with and without airflow through the duct are presented. Techniques are described for measuring cut-on frequencies, modal phase speed, and radial and annular mode shapes. The effects of flow velocity on cut-on frequencies and phase speed are measured. Comparisons are made with theoretical predictions for all of the effects studies. The two microphone method of impedance is used to measure the effects of flow on acoustic liners. A numerical study of sound propagation in annular ducts with one or both walls acoustically lined is presented.

Synthesis, crystal growth, characterization and theoretical studies of 4-aminobenzophenonium picrate

NASA Astrophysics Data System (ADS)

Aditya Prasad, A.; Muthu, K.; Rajasekar, M.; Meenatchi, V.; Meenakshisundaram, S. P.

2015-01-01

Single crystals of 4-aminobenzophenonium picrate (4ABPP) were grown by slow evaporation of a mixed solvent system methanol-acetone (1:1,v/v) containing equimolar quantities of picric acid and 4-aminobenzophenone. The proton and carbon signals are confirmed by nuclear magnetic resonance spectroscopy. The various functional groups present in the molecule are identified by FT-IR analysis. Optimized geometry, first-order molecular hyperpolarizability (β), polarizability (α), bond length, bond angles and excited state energy from theoretical UV were derived by Hartree-Fock calculations. The complete assignment of the vibrational modes for 4-aminobenzophenonium picrate was performed by the scaled quantum mechanics force field (SQMFF) methodology using potential energy distribution. Natural bond orbital (NBO) calculations were employed to study the stabilities arising from charge delocalization and intermolecular interactions of 4ABPP. The atomic charge distributions of the various atoms present in 4ABPP are obtained by Mulliken charge population analysis. The as-grown crystal is further characterized by thermal and optical absorbance studies.

Momentum distributions for H 2 ( e , e ' p )

DOE PAGES

Ford, William P.; Jeschonnek, Sabine; Van Orden, J. W.

2014-12-29

[Background] A primary goal of deuteron electrodisintegration is the possibility of extracting the deuteron momentum distribution. This extraction is inherently fraught with difficulty, as the momentum distribution is not an observable and the extraction relies on theoretical models dependent on other models as input. [Purpose] We present a new method for extracting the momentum distribution which takes into account a wide variety of model inputs thus providing a theoretical uncertainty due to the various model constituents. [Method] The calculations presented here are using a Bethe-Salpeter like formalism with a wide variety of bound state wave functions, form factors, and finalmore » state interactions. We present a method to extract the momentum distributions from experimental cross sections, which takes into account the theoretical uncertainty from the various model constituents entering the calculation. [Results] In order to test the extraction pseudo-data was generated, and the extracted "experimental'' distribution, which has theoretical uncertainty from the various model inputs, was compared with the theoretical distribution used to generate the pseudo-data. [Conclusions] In the examples we compared the original distribution was typically within the error band of the extracted distribution. The input wave functions do contain some outliers which are discussed in the text, but at least this process can provide an upper bound on the deuteron momentum distribution. Due to the reliance on the theoretical calculation to obtain this quantity any extraction method should account for the theoretical error inherent in these calculations due to model inputs.« less

PREFACE: 2nd International Workshop on Theoretical and Computational Physics (IWTCP-2): Modern Methods and Latest Results in Particle Physics, Nuclear Physics and Astrophysics and the 39th National Conference on Theoretical Physics (NCTP-39)

NASA Astrophysics Data System (ADS)

Hoang, Trinh Xuan; Ky, Nguyen Anh; Lan, Nguyen Tri; Viet, Nguyen Ai

2015-06-01

This volume contains selected papers presented at the 2nd International Workshop on Theoretical and Computational Physics (IWTCP-2): Modern Methods and Latest Results in Particle Physics, Nuclear Physics and Astrophysics and the 39th National Conference on Theoretical Physics (NCTP-39). Both the workshop and the conference were held from 28th - 31st July 2014 in Dakruco Hotel, Buon Ma Thuot, Dak Lak, Vietnam. The NCTP-39 and the IWTCP-2 were organized under the support of the Vietnamese Theoretical Physics Society, with a motivation to foster scientific exchanges between the theoretical and computational physicists in Vietnam and worldwide, as well as to promote high-standard level of research and education activities for young physicists in the country. The IWTCP-2 was also an External Activity of the Asia Pacific Center for Theoretical Physics (APCTP). About 100 participants coming from nine countries participated in the workshop and the conference. At the IWTCP-2 workshop, we had 16 invited talks presented by international experts, together with eight oral and ten poster contributions. At the NCTP-39, three invited talks, 15 oral contributions and 39 posters were presented. We would like to thank all invited speakers, participants and sponsors for making the workshop and the conference successful. Trinh Xuan Hoang, Nguyen Anh Ky, Nguyen Tri Lan and Nguyen Ai Viet

Exploring Occupational and Behavioral Risk Factors for Obesity in Firefighters: A Theoretical Framework and Study Design

PubMed Central

Schnall, Peter; Dobson, Marnie; Israel, Leslie; Landsbergis, Paul; Galassetti, Pietro; Pontello, Andria; Kojaku, Stacey; Baker, Dean

2011-01-01

Firefighters and police officers have the third highest prevalence of obesity among 41 male occupational groups in the United States (US). However, few studies have examined the relationship of firefighter working conditions and health behaviors with obesity. This paper presents a theoretical framework describing the relationship between working conditions, health behaviors, and obesity in firefighters. In addition, the paper describes a detailed study plan for exploring the role of occupational and behavioral risk factors in the development of obesity in firefighters enrolled in the Orange County Fire Authority Wellness Fitness Program. The study plan will be described with emphasis on its methodological merits: adopting a participatory action research approach, developing a firefighter-specific work and health questionnaire, conducting both a cross-sectional epidemiological study using the questionnaire and a sub-study to assess the validity of the questionnaire with dietary intake and physical activity measures, and evaluating the strengths and weaknesses of the body mass index as an obesity measure in comparison to skinfold-based percent body fat. The study plan based on a theoretical framework can be an essential first step for establishing effective intervention programs for obesity among professional and voluntary firefighters. PMID:22953214

Exploring occupational and behavioral risk factors for obesity in firefighters: a theoretical framework and study design.

PubMed

Choi, Bongkyoo; Schnall, Peter; Dobson, Marnie; Israel, Leslie; Landsbergis, Paul; Galassetti, Pietro; Pontello, Andria; Kojaku, Stacey; Baker, Dean

2011-12-01

Firefighters and police officers have the third highest prevalence of obesity among 41 male occupational groups in the United States (US). However, few studies have examined the relationship of firefighter working conditions and health behaviors with obesity. This paper presents a theoretical framework describing the relationship between working conditions, health behaviors, and obesity in firefighters. In addition, the paper describes a detailed study plan for exploring the role of occupational and behavioral risk factors in the development of obesity in firefighters enrolled in the Orange County Fire Authority Wellness Fitness Program. The study plan will be described with emphasis on its methodological merits: adopting a participatory action research approach, developing a firefighter-specific work and health questionnaire, conducting both a cross-sectional epidemiological study using the questionnaire and a sub-study to assess the validity of the questionnaire with dietary intake and physical activity measures, and evaluating the strengths and weaknesses of the body mass index as an obesity measure in comparison to skinfold-based percent body fat. The study plan based on a theoretical framework can be an essential first step for establishing effective intervention programs for obesity among professional and voluntary firefighters.

Measurements of Solar Vector Magnetic Fields

NASA Technical Reports Server (NTRS)

Hagyard, M. J. (Editor)

1985-01-01

Various aspects of the measurement of solar magnetic fields are presented. The four major subdivisions of the study are: (1) theoretical understanding of solar vector magnetic fields; (3) techniques for interpretation of observational data; and (4) techniques for data display.

Experimental Analysis of Algorithms.

DTIC Science & Technology

1987-12-01

solution ratio in the Bin Packing study) were suggested by theoretical analysis. Gnanadesikan and Gustafson [16] note that significantly different sizes...34’ [16] M. Gnanadesikan and H. W. Gustafson. * Properties of Performance Measures. 1985. Summary of poster presentation. Gnanadesikan is at Farleigh

Theory and Methodology in Researching Emotions in Education

ERIC Educational Resources Information Center

Zembylas, Michalinos

2007-01-01

Differing theoretical approaches to the study of emotions are presented: emotions as private (psychodynamic approaches); emotions as sociocultural phenomena (social constructionist approaches); and a third perspective (interactionist approaches) transcending these two. These approaches have important methodological implications in studying…

"AmI for health: chronic disease management".

PubMed

Arredondo, M T; Fico, G; Pastor, L

2011-01-01

Several students of Bioengineering complain about the excess of theoretical classes and the difficulty to assimilate the subject taught. This work presents a strategy to mix theory and practice when teaching, thus motivating students to engage in their studies.

A study of general instability of box beams with truss-type ribs

NASA Technical Reports Server (NTRS)

Lundquist, Eugene E; Schwartz, Edward B

1942-01-01

The design of truss-type ribs for box beams is theoretically treated with regard to the function of the ribs in stabilizing the compression flange. The theory is applied to a design problem, and the results of this application are presented and discussed in relation to the general problem of rib design. The results of some tests made as a part of this general study are presented in an appendix.

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

Builth-Williams, J. D.; Chiari, L.; Jones, D. B., E-mail: darryl.jones@flinders.edu.au, E-mail: michael.brunger@flinders.edu.au

We present experimental and theoretical results for the electron-impact ionization of the highest occupied molecular orbitals of tetrahydropyran and 1,4-dioxane. Using an (e,2e) technique in asymmetric coplanar kinematics, angular distributions of the slow ejected electron, with an energy of 20 eV, are measured when incident electrons at 250 eV ionize the target and scatter through an angle of either −10° or −15°. The data are compared with calculations performed at the molecular 3-body distorted wave level. Fair agreement between the theoretical model and the experimental measurements was observed. The similar structures for these targets provide key insights for assessing themore » limitations of the theoretical calculations. This study in turn facilitates an improved understanding of the dynamics in the ionization process.« less

Total Electron-Impact Ionization Cross-Sections of CFx and NFx (x = 1 - 3)

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Tarnovsky, Vladimir; Becker, Kurt H.; Kwak, Dochan (Technical Monitor)

2001-01-01

The discrepancy between experimental and theoretical total electron-impact ionization cross sections for a group of fluorides, CFx, and NFx, (x = 1 - 3), is attributed to the inadequacies in previous theoretical models. Cross-sections calculated using a recently developed siBED (simulation Binary-Encounter-Dipole) model that takes into account the shielding of the long-range dipole potential between the scattering electron and target are in agreement with experimentation. The present study also carefully reanalyzed the previously reported experimental data to account for the possibility of incomplete collection of fragment ions and the presence of ion-pair formation channels. For NF3, our experimental and theoretical cross-sections compare well with the total ionization cross-sections recently reported by Haaland et al. in the region below dication formation.

The spectroscopic (FT-IR, FT-Raman, UV) and first order hyperpolarizability, HOMO and LUMO analysis of 3-aminobenzophenone by density functional method

NASA Astrophysics Data System (ADS)

Karabacak, M.; Kurt, M.; Cinar, M.; Ayyappan, S.; Sudha, S.; Sundaraganesan, N.

In this work, experimental and theoretical study on the molecular structure and the vibrational spectra of 3-aminobenzophenone (3-ABP) is presented. The vibrational frequencies of the title compound were obtained theoretically by DFT/B3LYP calculations employing the standard 6-311++G(d,p) basis set for optimized geometry and were compared with Fourier transform infrared spectrum (FTIR) in the region of 400-4000 cm-1 and with Fourier Transform Raman spectrum in the region of 50-4000 cm-1. Complete vibrational assignments, analysis and correlation of the fundamental modes for the title compound were carried out. The vibrational harmonic frequencies were scaled using scale factor, yielding a good agreement between the experimentally recorded and the theoretically calculated values.

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

PubMed

Cowden, Tracy L; Cummings, Greta G

2015-01-01

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

Exploring Environmental Factors in Nursing Workplaces That Promote Psychological Resilience: Constructing a Unified Theoretical Model.

PubMed

Cusack, Lynette; Smith, Morgan; Hegney, Desley; Rees, Clare S; Breen, Lauren J; Witt, Regina R; Rogers, Cath; Williams, Allison; Cross, Wendy; Cheung, Kin

2016-01-01

Building nurses' resilience to complex and stressful practice environments is necessary to keep skilled nurses in the workplace and ensuring safe patient care. A unified theoretical framework titled Health Services Workplace Environmental Resilience Model (HSWERM), is presented to explain the environmental factors in the workplace that promote nurses' resilience. The framework builds on a previously-published theoretical model of individual resilience, which identified the key constructs of psychological resilience as self-efficacy, coping and mindfulness, but did not examine environmental factors in the workplace that promote nurses' resilience. This unified theoretical framework was developed using a literary synthesis drawing on data from international studies and literature reviews on the nursing workforce in hospitals. The most frequent workplace environmental factors were identified, extracted and clustered in alignment with key constructs for psychological resilience. Six major organizational concepts emerged that related to a positive resilience-building workplace and formed the foundation of the theoretical model. Three concepts related to nursing staff support (professional, practice, personal) and three related to nursing staff development (professional, practice, personal) within the workplace environment. The unified theoretical model incorporates these concepts within the workplace context, linking to the nurse, and then impacting on personal resilience and workplace outcomes, and its use has the potential to increase staff retention and quality of patient care.

Understanding personality from Ayurvedic perspective for psychological assessment: A case

PubMed Central

Shilpa, S; Venkatesha Murthy, C. G.

2011-01-01

The study of personality has fascinated psychologists since a long time. Personality as an area of study has grown so much that a wealth of literature is available. On the other hand, the socio-ethnic dynamics of human race in the emerging global village context provoking psychologists to develop a personality theory which can treat certain basic components of personality as invariants, so that irrespective of culture, race, and nativity could still be able to study personality which will have universal applicability and relevance, is still far away. In the above emerging backdrop, “Ayurveda” has perhaps an important role to play as it can enable providing a theoretical and empirical base of personality traits and types. These Ayurvedic concepts are applicable to all human beings irrespective of caste, color, sex or race. Therefore, it is interesting to build on the Ayurvedic knowledge which has already given us so much since time immemorial, and validate some of these issues related to personality from psychological perspective. There are already certain efforts in understanding Sattva, Rajas, and Tamas Gunas. It can be furthered so that a comprehensive personality picture can be generated, which can have implications for health, career, education and many other dimensions of life. The present paper is a theoretical attempt in developing such a personality proposition which can be validated. Thus, the present paper only builds a theoretical framework for their possible empirical validity. PMID:22131752

Internal performance predictions for Langley scramjet engine module

NASA Technical Reports Server (NTRS)

Pinckney, S. Z.

1978-01-01

A one dimensional theoretical method for the prediction of the internal performance of a scramjet engine is presented. The effects of changes in vehicle forebody flow parameters and characteristics on predicted thrust for the scramjet engine were evaluated using this method, and results are presented. A theoretical evaluation of the effects of changes in the scramjet engine's internal parameters is also presented. Theoretical internal performance predictions, in terms thrust coefficient and specific impulse, are provided for the scramjet engine for free stream Mach numbers of 5, 6, and 7 free stream dynamic pressure of 23,940 N/sq m forebody surface angles of 4.6 deg to 14.6 deg, and fuel equivalence ratio of 1.0.

A theoretical and mass spectrometry study of the fragmentation of mycosporine-like amino acids

NASA Astrophysics Data System (ADS)

Cardozo, Karina H. M.; Vessecchi, Ricardo; Carvalho, Valdemir M.; Pinto, Ernani; Gates, Paul J.; Colepicolo, Pio; Galembeck, Sérgio E.; Lopes, Norberto P.

2008-06-01

In the present study, the mycosporine-like amino acids (MAAs) were isolated from the marine red alga Gracilaria tenuistipitata and analysed by high-resolution accurate-mass sequential mass spectrometry (MSn). In addition to the proposed fragmentation mechanism based on the MSn analysis, it is clearly demonstrated that the elimination of mass 15 is a radical processes taking place at the methoxyl substituent of the double bond. This characteristic loss of a methyl radical was studied by theoretical calculations and the homolytic cleavage of the OC bond is suggested to be dependent on the bond weakening. The protonation site of the MAAs was indicated by analysis of the Fukui functions and the relative Gibbs energies of the several possible protonated forms.

Computational models of neuromodulation.

PubMed

Fellous, J M; Linster, C

1998-05-15

Computational modeling of neural substrates provides an excellent theoretical framework for the understanding of the computational roles of neuromodulation. In this review, we illustrate, with a large number of modeling studies, the specific computations performed by neuromodulation in the context of various neural models of invertebrate and vertebrate preparations. We base our characterization of neuromodulations on their computational and functional roles rather than on anatomical or chemical criteria. We review the main framework in which neuromodulation has been studied theoretically (central pattern generation and oscillations, sensory processing, memory and information integration). Finally, we present a detailed mathematical overview of how neuromodulation has been implemented at the single cell and network levels in modeling studies. Overall, neuromodulation is found to increase and control computational complexity.

Integrating the Constructs of Anosognosia and Metacognition: A Review of Recent Findings in Dementia

PubMed Central

Sunderaraman, Preeti; Cosentino, Stephanie

2017-01-01

The current review integrates recent findings regarding the construct of self-awareness in dementia from both clinical and cognitive perspectives. We present the predominant theoretical models of awareness, and summarize both traditional and emerging approaches to assessing awareness from clinical and metacognitive perspectives. In this review, we focus primarily on findings from recent studies in anosognosia and metacognition in the context of neurodegenerative disease with special emphasis on Alzheimer's disease and Frontotemporal dementia. Emerging trends in the study of awareness, including examination of the longitudinal course of anosognosia, and investigation of the neural substrates underlying metacognitive abilities are addressed. Finally, the practical importance of studying and assessing awareness from both theoretical and clinical angles is emphasized. PMID:28283961

Integrating the Constructs of Anosognosia and Metacognition: a Review of Recent Findings in Dementia.

PubMed

Sunderaraman, Preeti; Cosentino, Stephanie

2017-03-01

The current review integrates recent findings regarding the construct of self-awareness in dementia from both clinical and cognitive perspectives. We present the predominant theoretical models of awareness and summarize both traditional and emerging approaches to assessing awareness from clinical and meta-cognitive perspectives. In this review, we focus primarily on findings from recent studies in anosognosia and meta-cognition in the context of neurodegenerative disease with special emphasis on Alzheimer's disease and frontotemporal dementia. Emerging trends in the study of awareness, including examination of the longitudinal course of anosognosia, and investigation of the neural substrates underlying meta-cognitive abilities are addressed. Finally, the practical importance of studying and assessing awareness from both theoretical and clinical angles is emphasized.

KEWPIE2: A cascade code for the study of dynamical decay of excited nuclei

NASA Astrophysics Data System (ADS)

Lü, Hongliang; Marchix, Anthony; Abe, Yasuhisa; Boilley, David

2016-03-01

KEWPIE-a cascade code devoted to investigating the dynamical decay of excited nuclei, specially designed for treating very low probability events related to the synthesis of super-heavy nuclei formed in fusion-evaporation reactions-has been improved and rewritten in C++ programming language to become KEWPIE2. The current version of the code comprises various nuclear models concerning the light-particle emission, fission process and statistical properties of excited nuclei. General features of the code, such as the numerical scheme and the main physical ingredients, are described in detail. Some typical calculations having been performed in the present paper clearly show that theoretical predictions are generally in accordance with experimental data. Furthermore, since the values of some input parameters cannot be determined neither theoretically nor experimentally, a sensibility analysis is presented. To this end, we systematically investigate the effects of using different parameter values and reaction models on the final results. As expected, in the case of heavy nuclei, the fission process has the most crucial role to play in theoretical predictions. This work would be essential for numerical modeling of fusion-evaporation reactions.

What neuropsychology tells us about human tool use? The four constraints theory (4CT): mechanics, space, time, and effort.

PubMed

Osiurak, François

2014-06-01

Our understanding of human tool use comes mainly from neuropsychology, particularly from patients with apraxia or action disorganization syndrome. However, there is no integrative, theoretical framework explaining what these neuropsychological syndromes tell us about the cognitive/neural bases of human tool use. The goal of the present article is to fill this gap, by providing a theoretical framework for the study of human tool use: The Four Constraints Theory (4CT). This theory rests on two basic assumptions. First, everyday tool use activities can be formalized as multiple problem situations consisted of four distinct constraints (mechanics, space, time, and effort). Second, each of these constraints can be solved by the means of a specific process (technical reasoning, semantic reasoning, working memory, and simulation-based decision-making, respectively). Besides presenting neuropsychological evidence for 4CT, this article shall address epistemological, theoretical and methodological issues I will attempt to resolve. This article will discuss how 4CT diverges from current cognitive models about several widespread hypotheses (e.g., notion of routine, direct and automatic activation of tool knowledge, simulation-based tool knowledge).

Theoretical Design of a Two-Photon Fluorescent Probe for Nitric Oxide with Enhanced Emission Induced by Photoninduced Electron Transfer.

PubMed

Zhang, Yujin; Leng, Jiancai; Hu, Wei

2018-04-25

In the present work, we systematically investigate the sensing abilities of two recently literature-reported two-photon fluorescent NO probes, i.e., the o-phenylenediamine derivative of Nile Red and the p-phenylenediamine derivative of coumarin. The recognition mechanisms of these probes are studied by using the molecular orbital classifying method, which demonstrates the photoinduced electron transfer process. In addition, we have designed two new probes by swapping receptor units present on fluorophores, i.e., the p-phenylenediamine derivative of Nile Red and the o-phenylenediamine derivative of coumarin. However, it illustrates that only the latter has ability to function as off-on typed fluorescent probe for NO. More importantly, calculations on the two-photon absorption properties of the probes demonstrate that both receptor derivatives of coumarin possess larger TPA cross-sections than Nile Red derivatives, which makes a better two photon fluorescent probe. Our theoretical investigations reveal that the underlying mechanism satisfactorily explain the experimental results, providing a theoretical basis on the structure-property relationships which is beneficial to developing new two-photon fluorescent probes for NO.

Design and characterization of a magnetoelastic sensor for the detection of biological agents

NASA Astrophysics Data System (ADS)

Shen, Wen; Mathison, Leslie C.; Petrenko, Valery A.; Chin, Bryan A.

2010-01-01

This paper presents the design and development of a free-standing, magnetoelastic biosensor. The detection principle is presented and various resonance characteristics of the sensor are discussed. Experimental measurements of the sensor resonance frequencies agree with theoretical predictions. The influence of the external magnetic field on the resonance behaviour of the sensor was studied and the optimum dc magnetic fields for best sensitivity in air and in water solutions for 2000 × 400 × 15 µm (2 mm) sensors and 1000 × 200 × 15 µm (1 mm) size sensors were determined to be 75 Oe and 38 Oe, respectively. Both theoretical prediction and experimental results show that smaller sensors have greater mass sensitivity and can theoretically detect mass as small as one biological spore. The sensor platform was immobilized with JRB7 phages for specific, in vitro detection of B. anthracis spores. Real-time detection of spores suspended in water was demonstrated using a flowing system. The 1 mm and 2 mm sensors were found to have a detection limit of 104 spores ml-1 and 105 spores ml-1, respectively.

Full kinetics investigation of the formation reaction of phosphonate esters in the gas-phase: a theoretical study.

PubMed

Kazemian, Mohammad Amin; Habibi-Khorassani, Sayyed Mostafa; Maghsoodlu, Malek Taher; Ebrahimi, Ali

2014-04-01

In the present work, the proposed multiple-mechanisms have been investigated theoretically for the reaction between triphenyl phosphite and dimethyl acetylenedicarboxylate in the presence of N-H acid such as aniline for generation of phosphonate esters using ab initio molecular orbital theory in gas phase. The profile of the potential energy surface was constructed at the HF/6-311G(d,p) level of theory. The kinetics of the gas phase reaction was studied by evaluating the reaction path of various mechanisms. Between 12 speculative proposed mechanisms {step₁, step₂ (with four possibilities), step₃ (with three possibilities), and step₄} only the third speculative mechanism was recognized as a desirable mechanism. Theoretical kinetics data involving k and E(a), activation (ΔG(‡), ΔS(‡) and ΔH(‡)), and thermodynamic parameters (ΔG°, ΔS° and ΔH°) were calculated for each step of the various mechanisms. Step₁ of the desirable mechanism was identified as the rate determining step. Comparison of the theoretical desirable mechanism with the rate law that has been previously obtained by UV spectrophotometry experiments indicated that the results are in good agreement.

Experimental and theoretical study of substituent effect on 13C NMR chemical shifts of 5-arylidene-2,4-thiazolidinediones

NASA Astrophysics Data System (ADS)

Rančić, Milica P.; Trišović, Nemanja P.; Milčić, Miloš K.; Ajaj, Ismail A.; Marinković, Aleksandar D.

2013-10-01

The electronic structure of 5-arylidene-2,4-thiazolidinediones has been studied by using experimental and theoretical methodology. The theoretical calculations of the investigated 5-arylidene-2,4-thiazolidinediones have been performed by the use of quantum chemical methods. The calculated 13C NMR chemical shifts and NBO atomic charges provide an insight into the influence of such a structure on the transmission of electronic substituent effects. Linear free energy relationships (LFERs) have been further applied to their 13C NMR chemical shifts. The correlation analyses for the substituent-induced chemical shifts (SCS) have been performed with σ using SSP (single substituent parameter), field (σF) and resonance (σR) parameters using DSP (dual substituent parameter), as well as the Yukawa-Tsuno model. The presented correlations account satisfactorily for the polar and resonance substituent effects operative at Cβ, and C7 carbons, while reverse substituent effect was found for Cα. The comparison of correlation results for the investigated molecules with those obtained for seven structurally related styrene series has indicated that specific cross-interaction of phenyl substituent and groups attached at Cβ carbon causes increased sensitivity of SCS Cβ to the resonance effect with increasing of electron-accepting capabilities of the group present at Cβ.

Theoretical study of turbulent channel flow - Bulk properties, pressure fluctuations, and propagation of electromagnetic waves

NASA Technical Reports Server (NTRS)

Canuto, V. M.; Hartke, G. J.; Battaglia, A.; Chasnov, J.; Albrecht, G. F.

1990-01-01

In this paper, we apply two theoretical turbulence models, DIA and the recent GISS model, to study properties of a turbulent channel flow. Both models provide a turbulent kinetic energy spectral function E(k) as the solution of a non-linear equation; the two models employ the same source function but different closures. The source function is characterized by a rate n sub s (k) which is derived from the complex eigenvalues of the Orr-Sommerfeld (OS) equation in which the basic flow is taken to be of a Poiseuille type. The O-S equation is solved for a variety of Reynolds numbers corresponding to available experimental data. A physical argument is presented whereby the central line velocity characterizing the basic flow, U0 sup L, is not to be identified with the U0 appearing in the experimental Reynolds number. The theoretical results are compared with two types of experimental data: (1) turbulence bulk properties, and (2) properties that depend strongly on the structure of the turbulence spectrum at low wave numbers. The only existing analytical expression for Pi (k) cannot be used in the present case because it applies to the case of a flat plate, not a finite channel.

At Odds: Reconciling Experimental and Theoretical Results in High School Physics

ERIC Educational Resources Information Center

Gates, Joshua

2009-01-01

For this experiment, students are divided into 2 groups and presented with a static equilibrium force-balance problem to solve. One group works entirely experimentally and the other group theoretically, using Newton's laws. The groups present their seemingly dissimilar results and must reconcile them through discussion. (Contains 3 figures.)

The composition of heterogeneous control laws

NASA Technical Reports Server (NTRS)

Kuipers, Benjamin; Astrom, Karl

1991-01-01

The fuzzy control literature and industrial practice provide certain nonlinear methods for combining heterogeneous control laws, but these methods have been very difficult to analyze theoretically. An alternate formulation and extension of this approach is presented that has several practical and theoretical benefits. An example of heterogeneous control is given and two alternate analysis methods are presented.

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

ERIC Educational Resources Information Center

Hogarth, Melitta

2017-01-01

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

A density functional theory study on the thermodynamic and dynamic properties of anthraquinone analogue cathode materials for rechargeable lithium ion batteries.

PubMed

Yang, Shu-Jing; Qin, Xiao-Ya; He, Rongxing; Shen, Wei; Li, Ming; Zhao, Liu-Bin

2017-05-21

Organic redox compounds have become the emerging electrode materials for rechargeable lithium ion batteries. The high electrochemical performance provides organic electrode materials with great opportunities to be applied in electric energy storage devices. Among the different types of organic materials, conjugated carbonyl compounds are the most promising type at present, because only they can simultaneously achieve, high energy density, high cycling stability, and high power density. In this research, a series of heteroatom substituted anthraquinone (AQ) derivatives were designed theoretically so that the high theoretical capacity of AQ remained. The discharge and charge mechanism as well as the thermodynamic and dynamic properties of AQ and its derivatives were investigated using first-principles density functional theory. Using heteroatom substitution, both the thermodynamic and dynamic properties of AQ as cathode materials could be largely improved. Among these conjugated carboxyl compounds, BDOZD and BDIOZD with a simultaneously high theoretical capacity and high working potential exhibit the largest energy density of about 780 W h kg -1 , which is 41% larger than that of AQ. The PQD with the smallest value of λ gives the largest charge transfer rate constant, which is about four times as large as the prototype molecule, AQ. The most interesting finding is that the lithium ion transfer plays a very important role in influencing both the discharge potential and electrochemical charge transfer rate. The present study illustrates that theoretical calculations provide a highly effective way to discover potential materials for use with rechargeable lithium ion batteries.

Parametric study of closed wet cooling tower thermal performance

NASA Astrophysics Data System (ADS)

Qasim, S. M.; Hayder, M. J.

2017-08-01

The present study involves experimental and theoretical analysis to evaluate the thermal performance of modified Closed Wet Cooling Tower (CWCT). The experimental study includes: design, manufacture and testing prototype of a modified counter flow forced draft CWCT. The modification based on addition packing to the conventional CWCT. A series of experiments was carried out at different operational parameters. In view of energy analysis, the thermal performance parameters of the tower are: cooling range, tower approach, cooling capacity, thermal efficiency, heat and mass transfer coefficients. The theoretical study included develops Artificial Neural Network (ANN) models to predicting various thermal performance parameters of the tower. Utilizing experimental data for training and testing, the models simulated by multi-layer back propagation algorithm for varying all operational parameters stated in experimental test.

Two Year Community: Design and Components of a Two-Year College Interdisciplinary Field-Study Course

ERIC Educational Resources Information Center

Wolfe, Benjamin A.; Martin, Todd C.

2013-01-01

Interdisciplinary field study courses at 2-year colleges can provide an opportunity to enhance student learning. The authors present here an 11-day interdisciplinary field-study course designed for nonscience majors at a 2-year college. Using a theoretical learning framework that emphasizes cognitive and metacognitive gains, the field study…

Old and New Ways to Study Characteristics of Reading Disability: The Case of the Nonword-Reading Deficit

ERIC Educational Resources Information Center

Van den Broeck, Wim; Geudens, Astrid

2012-01-01

Theoretical and computational models of reading have traditionally been informed by specific characteristics of disabled readers. One of the most frequently studied marker effects of developmental dyslexia is the nonword-reading deficit. Disabled readers are generally believed to show a specific problem in reading nonwords. This study presents a…

A Study of Taiwanese Children's Conceptions of and Relation to Nature: Curricular and Policy Implications

ERIC Educational Resources Information Center

Dai, Amy Hsin-I

2011-01-01

The present study investigated children's conceptions of and relations to nature. Understanding the factors that influence them was the goal. The study used the Contextual Model of Learning as the theoretical framework to structure the research questions and data analysis to understand children's nature learning in the personal, sociocultural, and…

Re-Exploring Game-Assisted Learning Research: The Perspective of Learning Theoretical Bases

ERIC Educational Resources Information Center

Wu, Wen-Hsiung; Chiou, Wen-Bin; Kao, Hao-Yun; Hu, Chung-Hsing Alex; Huang, Sih-Han

2012-01-01

Previous literature reviews or meta-analysis based studies on game-assisted learning have provided important results, but few studies have considered the importance of learning theory, and coverage of papers after 2007 is scant. This study presents a systematic review of the literature using a meta-analysis approach to provide a more comprehensive…

Predicting Post-Treatment-Initiation Alcohol Use among Patients with Severe Mental Illness and Alcohol Use Disorders

ERIC Educational Resources Information Center

Bradizza, Clara M.; Maisto, Stephen A.; Vincent, Paula C.; Stasiewicz, Paul R.; Connors, Gerard J.; Mercer, Nicole D.

2009-01-01

Few investigators studying alcohol abuse among individuals with a severe mental illness (SMI) have examined predictors of posttreatment alcohol outcomes. In the present study, a multivariate approach based on a theoretical model was used to study the relationship between psychosocial factors and post-treatment-initiation alcohol use. Predictors of…

Community-Based Financial Literacy Education in a Cultural Context: A Study of Teacher Beliefs and Pedagogical Practice

ERIC Educational Resources Information Center

Tisdell, Elizabeth J.; Taylor, Edward W.; Forte, Karin Sprow

2013-01-01

This article presents the findings related to teaching beliefs and pedagogical practices of a study that examined how financial literacy educators educate adults from underserved population groups in community-based settings. The study is theoretically framed in the teaching beliefs and culturally responsive education literature. Findings reveal a…

A Review on Studies of Phrasal Verb Constructions in ESL Context

ERIC Educational Resources Information Center

Jahedi, Maryam; Mukundan, Jayakaran

2015-01-01

This paper aims to give an overview of studies on phrasal verbs in three decades to present the theoretical and methodological issues, as well as the findings of research. Moreover, this review reveals the developments and paradigm shifts occurred in this area. Previous studies have shown that the research findings have not been incorporated into…

Penetration with Long Rods: A Theoretical Framework and Comparison with Instrumented Impacts

DTIC Science & Technology

1981-05-01

program to begin probing the details of the interaction process. The theoretical framework underlying such a program is explained in detail. The theory of...of the time sequence of events during penetration. Data from one series of experiments, reported in detail elsewhere, is presented and discussed within the theoretical framework .

An Epistemological Analysis of the Evolution of Didactical Activities in Teaching-Learning Sequences: The Case of Fluids. Special Issue

ERIC Educational Resources Information Center

Psillos, D.; Tselfes, Vassilis; Kariotoglou, Petros

2004-01-01

In the present paper we propose a theoretical framework for an epistemological modelling of teaching-learning (didactical) activities, which draws on recent studies of scientific practice. We present and analyse the framework, which includes three categories: namely, Cosmos-Evidence-Ideas (CEI). We also apply this framework in order to model a…

Cross section of resonant Raman scattering of light by polyenes

NASA Astrophysics Data System (ADS)

Verdyugin, V. V.; Burshteyn, K. Ya.; Shorygin, P. P.

1987-03-01

An experimental study is presented of the resonant Raman spectra of beta carotene. Absolute differential cross sections are obtained for the most intensive Raman spectral lines with excitation at the absorption maximum. A theoretical analysis is presented of the variation in absolute differential cross section as a function of a number of conjunct double bonds in the polyenes.

The 1980 Large space systems technology. Volume 2: Base technology

NASA Technical Reports Server (NTRS)

Kopriver, F., III (Compiler)

1981-01-01

Technology pertinent to large antenna systems, technology related to large space platform systems, and base technology applicable to both antenna and platform systems are discussed. Design studies, structural testing results, and theoretical applications are presented with accompanying validation data. A total systems approach including controls, platforms, and antennas is presented as a cohesive, programmatic plan for large space systems.

Using Multisite Experiments to Study Cross-Site Variation in Treatment Effects: A Hybrid Approach with Fixed Intercepts and A Random Treatment Coefficient

ERIC Educational Resources Information Center

Bloom, Howard S.; Raudenbush, Stephen W.; Weiss, Michael J.; Porter, Kristin

2017-01-01

The present article considers a fundamental question in evaluation research: "By how much do program effects vary across sites?" The article first presents a theoretical model of cross-site impact variation and a related estimation model with a random treatment coefficient and fixed site-specific intercepts. This approach eliminates…

Theoretical investigation of polarization effects in solution: Importance of solvent collective motions

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

Ishida, Tateki

2015-01-22

Recent theoretical studies on interesting topics related to polarization effects in solutions are presented. As one of interesting topics, ionic liquids (ILs) solvents are focused on. The collective dynamics of electronic polarizability through interionic dynamics and the effect of polarization in ILs, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF{sub 6}]), are studied with molecular dynamics simulation. Also, the time-dependent polarization effect on the probe betaine dye molecule, pyridinium N-phenoxide, in water is investigated by a time-dependent reference interaction site model self-consistent field (time-dependent RISM-SCF) approach. The importance of considering polarization effects on solution systems related to solvent collective motions is shown.

Some considerations in the combustion of AP/composite propellants

NASA Technical Reports Server (NTRS)

Kumar, R. N.

1972-01-01

Theoretical studies are presented on the time-independent and oscillatory combustion of nonmetallized AP/composite propellants. Three hypotheses are introduced: (1) The extent of propellant degradation at the vaporization step has to be specified through a scientific criterion. (2) The condensed phase degradation reaction of ammonium perchlorate to a vaporizable state is the overall rate-limiting step. (3) Gas phase combustion rate is controlled by the mixing rate of fuel and oxidizer vapors. In the treatment of oscillatory combustion, the assumption of quasi-steady fluctuations in the gas phase is used to supplement these hypotheses. In comparison with experimental data, this study predicts several of the observations including a few that remain inconsistent with theoretical results.

Explaining the use of text-based communication media: an examination of three theories of media use.

PubMed

Park, Namkee; Chung, Jae Eun; Lee, Seungyoon

2012-07-01

The present study examined the factors associated with individuals' use of three different text-based communication media: e-mail, cell-phone texting, and Facebook Wall postings. Three theoretical perspectives, including media richness theory, uses and gratifications, and perceived network effects, were examined. Using data from a survey of college students (N=280), the study found that the theoretical constructs from these theories play different roles when applied to different technologies. The results suggest that a simultaneous consideration of technological attributes, users' motivations, and social circumstances in which users select and use the technology is useful for fully understanding the dynamics of the selection and the use of a given technology.

Current perspectives on the biological study of play: signs of progress.

PubMed

Graham, Kerrie Lewis; Burghardt, Gordon M

2010-12-01

There has been a recent resurgence of interest in the study of play behavior, marked by much empirical research and theoretical review. These efforts suggest that play may be of greater biological significance than most scientists realize. Here we present a brief synopsis of current play research covering issues of adaptive function, phylogeny, causal mechanisms, and development. Our goal is to selectively highlight contemporary areas of research in which the underlying processes and consequences of play should not be ignored. We elucidate some of the new and burgeoning areas of play research and interpret them from an integrative biological theoretical perspective that highlights areas in need of further experimental, comparative, and field research.

Tensile buckling of advanced turboprops

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Aiello, R. A.

1982-01-01

Theoretical studies were conducted to determine analytically the tensile buckling of advanced propeller blades (turboprops) in centrifugal fields, as well as the effects of tensile buckling on other types of structural behavior, such as resonant frequencies and flutter. Theoretical studies were also conducted to establish the advantages of using high performance composite turboprops as compared to titanium. Results show that the vibration frequencies are not affected appreciably prior to 80 percent of the tensile speed. Some frequencies approach zero as the tensile buckling speed is approached. Composites provide a substantial advantage over titanium on a buckling speed to weight basis. Vibration modes change as the rotor speed is increased and substantial geometric coupling is present.

Effects of structural differences on the NMR chemical shifts in cinnamic acid derivatives: Comparison of GIAO and GIPAW calculations

NASA Astrophysics Data System (ADS)

Szeleszczuk, Łukasz; Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika; Wawer, Iwona

2016-06-01

In this article we report the results of combined theoretical and experimental structural studies on cinnamic acid derivatives (CADs), one of the main groups of secondary metabolites present in various medicinal plant species and food products of plant origin. The effects of structural differences in CADs on their spectroscopic properties were studied in detail by both: solid-state NMR and GIAO/GIPAW calculations. Theoretical computations were used in order to perform signal assignment in 13C CP/MAS NMR spectra of the cinnamic, o-coumaric, m-coumaric, p-coumaric, caffeic, ferulic, sinapic and 3,4-dimethoxycinnamic acids, and to evaluate the accuracy of GIPAW and GIAO methodology.

Designing a Double-Pole Nanoscale Relay Based on a Carbon Nanotube: A Theoretical Study

NASA Astrophysics Data System (ADS)

Mu, Weihua; Ou-Yang, Zhong-can; Dresselhaus, Mildred S.

2017-08-01

We theoretically investigate a novel and powerful double-pole nanoscale relay based on a carbon nanotube, which is one of the nanoelectromechanical switches being able to work under the strong nuclear radiation, and analyze the physical mechanism of the operating stages in the operation, including "pull in," "connection," and "pull back," as well as the key factors influencing the efficiency of the devices. We explicitly provide the analytical expression of the two important operation voltages, Vpull in and Vpull back , therefore clearly showing the dependence of the material properties and geometry of the present devices by the analytical method from basic physics, avoiding complex numerical calculations. Our method is easy to use in preparing the design guide for fabricating the present device and other nanoelectromechanical devices.

Comparison of wind tunnel test results at free stream Mach 0.7 with results from the Boeing TEA-230 subsonic flow method. [wing flow method tests

NASA Technical Reports Server (NTRS)

Mohn, L. W.

1975-01-01

The use of the Boeing TEA-230 Subsonic Flow Analysis method as a primary design tool in the development of cruise overwing nacelle configurations is presented. Surface pressure characteristics at 0.7 Mach number were determined by the TEA-230 method for a selected overwing flow-through nacelle configuration. Results of this analysis show excellent overall agreement with corresponding wind tunnel data. Effects of the presence of the nacelle on the wing pressure field were predicted accurately by the theoretical method. Evidence is provided that differences between theoretical and experimental pressure distributions in the present study would not result in significant discrepancies in the nacelle lines or nacelle drag estimates.

Absorption effects in electron-sulfur-dioxide collisions

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

Machado, L. E.; Sugohara, R. T.; Santos, A. S. dos

2011-09-15

A joint experimental-theoretical study on electron-SO{sub 2} collisions in the low and intermediate energy range is reported. More specifically, experimental elastic differential, integral, and momentum transfer cross sections in absolute scale are measured in the 100-1000 eV energy range using the relative-flow technique. Calculated elastic differential, integral, and momentum transfer cross sections as well as grand-total and total absorption cross sections are also presented in the 1-1000 eV energy range. A complex optical potential is used to represent the electron-molecule interaction dynamics, whereas the Schwinger variational iterative method combined with the distorted-wave approximation is used to solve the scattering equations.more » Comparison of the present results is made with the theoretical and experimental results available in the literature.« less

A study of methods of prediction and measurement of the transmission of sound through the walls of light aircraft

NASA Technical Reports Server (NTRS)

Forssen, B.; Wang, Y. S.; Raju, P. K.; Crocker, M. J.

1981-01-01

The acoustic intensity technique was applied to the sound transmission loss of panel structures (single, composite, and stiffened). A theoretical model of sound transmission through a cylindrical shell is presented.

High speed hydrogen/graphite interaction

NASA Technical Reports Server (NTRS)

Kelly, A. J.; Hamman, R.; Sharma, O. P.; Harrje, D. T.

1974-01-01

Various aspects of a research program on high speed hydrogen/graphite interaction are presented. Major areas discussed are: (1) theoretical predictions of hydrogen/graphite erosion rates; (2) high temperature, nonequilibrium hydrogen flow in a nozzle; and (3) molecular beam studies of hydrogen/graphite erosion.

A study of methods of prediction and measurement of the transmission of sound through the walls of light aircraft

NASA Astrophysics Data System (ADS)

Forssen, B.; Wang, Y. S.; Raju, P. K.; Crocker, M. J.

1981-08-01

The acoustic intensity technique was applied to the sound transmission loss of panel structures (single, composite, and stiffened). A theoretical model of sound transmission through a cylindrical shell is presented.

Organic Materials For Optical Switching

NASA Technical Reports Server (NTRS)

Cardelino, Beatriz H.

1993-01-01

Equations predict properties of candidate materials. Report presents results of theoretical study of nonlinear optical properties of organic materials. Such materials used in optical switching devices for computers and telecommunications, replacing electronic switches. Optical switching potentially offers extremely high information throughout in compact hardware.

Theory and Computation of Optimal Low- and Medium- Thrust Orbit Transfers

NASA Technical Reports Server (NTRS)

Goodson, Troy D.; Chuang, Jason C. H.; Ledsinger, Laura A.

1996-01-01

This report presents new theoretical results which lead to new algorithms for the computation of fuel-optimal multiple-burn orbit transfers of low and medium thrust. Theoretical results introduced herein show how to add burns to an optimal trajectory and show that the traditional set of necessary conditions may be replaced with a much simpler set of equations. Numerical results are presented to demonstrate the utility of the theoretical results and the new algorithms. Two indirect methods from the literature are shown to be effective for the optimal orbit transfer problem with relatively small numbers of burns. These methods are the Minimizing Boundary Condition Method (MBCM) and BOUNDSCO. Both of these methods make use of the first-order necessary conditions exactly as derived by optimal control theory. Perturbations due to Earth's oblateness and atmospheric drag are considered. These perturbations are of greatest interest for transfers that take place between low Earth orbit altitudes and geosynchronous orbit altitudes. Example extremal solutions including these effects and computed by the aforementioned methods are presented. An investigation is also made into a suboptimal multiple-burn guidance scheme. The FORTRAN code developed for this study has been collected together in a package named ORBPACK. ORBPACK's user manual is provided as an appendix to this report.

Ab Initio Studies of Shock-Induced Chemical Reactions of Inter-Metallics

NASA Astrophysics Data System (ADS)

Zaharieva, Roussislava; Hanagud, Sathya

2009-06-01

Shock-induced and shock assisted chemical reactions of intermetallic mixtures are studied by many researchers, using both experimental and theoretical techniques. The theoretical studies are primarily at continuum scales. The model frameworks include mixture theories and meso-scale models of grains of porous mixtures. The reaction models vary from equilibrium thermodynamic model to several non-equilibrium thermodynamic models. The shock-effects are primarily studied using appropriate conservation equations and numerical techniques to integrate the equations. All these models require material constants from experiments and estimates of transition states. Thus, the objective of this paper is to present studies based on ab initio techniques. The ab inito studies, to date, use ab inito molecular dynamics. This paper presents a study that uses shock pressures, and associated temperatures as starting variables. Then intermetallic mixtures are modeled as slabs. The required shock stresses are created by straining the lattice. Then, ab initio binding energy calculations are used to examine the stability of the reactions. Binding energies are obtained for different strain components super imposed on uniform compression and finite temperatures. Then, vibrational frequencies and nudge elastic band techniques are used to study reactivity and transition states. Examples include Ni and Al.

DNA in the material world: electrical properties and nano-applications.

PubMed

Triberis, Georgios P; Dimakogianni, Margarita

2009-01-01

Contradictory experimental findings and theoretical interpretations have spurred intense debate over the electrical properties of the DNA double helix. In the present review article the various factors responsible for these divergences are discussed. The enlightenment of this issue could improve long range chemistry of oxidative DNA damage and repair processes, monitoring protein-DNA interactions and possible applications in nano-electronic circuit technology. The update experimental situation concerning measurements of the electrical conductivity is given. The character of the carriers responsible for the electrical conductivity measured in DNA is investigated. A theoretical model for the temperature dependence of the electrical conductivity of DNA is presented, based on microscopic models and percolation theoretical arguments. The theoretical results, excluding or including correlation effects, are applied to recent experimental findings for DNA, considering it as a one dimensional molecular wire. The results indicate that correlation effects are probably responsible for large hopping distances in DNA samples. Other theoretical conductivity models proposed for the interpretation of the responsible transport mechanism are also reviewed. Some of the most known and pioneering works on DNA's nano-applications, future developments and perspectives along with current technological limitations and patents are presented and discussed.

Changing Fatherhood: An Exploratory Qualitative Study with African and African Caribbean Men in England

ERIC Educational Resources Information Center

Williams, Robert; Hewison, Alistair; Wildman, Stuart; Roskell, Carolyn

2013-01-01

This paper presents findings from a qualitative study undertaken with 46 African and African Caribbean men exploring their experiences of fatherhood. Data analysis was informed by Connell's theoretical work on changing gender relations. Findings indicate that fathers' lives were mediated by masculinities, racism, gender, migration and generational…

The Impact of Attachment Security and Emotion Dysregulation on Anxiety in Children and Adolescents

ERIC Educational Resources Information Center

Bender, Patrick K.; Sømhovd, Mikael; Pons, Francisco; Reinholdt-Dunne, Marie L.; Esbjørn, Barbara H.

2015-01-01

Theoretical views and empirical findings suggest interrelations among attachment security, emotion dysregulation and anxiety in childhood and adolescence. However, the associations among the three constructs have rarely been investigated in children, and no study has yet addressed these associations in adolescence. The aim of the present study was…

Developing a Conceptual Framework for Participatory Design of Psychosocial and Physical Learning Environments

ERIC Educational Resources Information Center

Mäkelä, Tiina; Helfenstein, Sacha

2016-01-01

The present study shows how the mixed-methods approach can be used in capturing and organising learning environment (LE) characteristics for the participatory design of psychosocial and physical LEs involving learners. Theoretical constructs were tested and further elaborated on in the analysis of two similar educational design research studies:…

Developing Young Adolescents' Self-Regulation by Means of Formative Assessment: A Theoretical Perspective

ERIC Educational Resources Information Center

Meusen-Beekman, Kelly D.; Joosten-ten Brinke, Desirée; Boshuizen, Henny P. A.

2015-01-01

Fostering self-regulated learning (SRL) has become increasingly important at various educational levels. Most studies on SRL have been conducted in higher education. The present literature study aims toward understanding self-regulation processes of students in primary and secondary education. We explored the development of young students'…

Theory Of Dewetting In A Filled Elastomer Under Stress

NASA Technical Reports Server (NTRS)

Peng, Steven T. J.

1993-01-01

Report presents theoretical study of dewetting between elastomeric binder and filler particles of highly filled elastomer under multiaxial tension and resulting dilatation of elastomer. Study directed toward understanding and predicting nonlinear stress-vs.-strain behavior of filled elastomeric rocket propellant, also applicable to rubber in highly loaded tire or in damping pad.

In Which Ways and to What Extent Do English and Shanghai Students Understand Linear Function?

ERIC Educational Resources Information Center

Wang, Yuqian; Barmby, Patrick; Bolden, David

2017-01-01

This study investigates how students in England and Shanghai understand linear function. Understanding is defined theoretically in terms of five hierarchical levels: Dependent Relationship; Connecting Representations; Property Noticing; Object Analysis; and Inventising. A pilot study instrument presented a set of problems to both cohorts, showing…

Dialectical Features of Students' Argumentation: A Critical Review of Argumentation Studies in Science Education

ERIC Educational Resources Information Center

Nielsen, Jan Alexis

2013-01-01

This paper explores the challenges of using the Toulmin model to analyze students' dialogical argumentation. The paper presents a theoretical exposition of what is involved in an empirical study of real dialogic argumentation. Dialogic argumentation embodies dialectical features--i.e. the features that are operative when students collaboratively…

Education for Human Rights. An International Perspective. Studies in Comparative Education.

ERIC Educational Resources Information Center

Ray, Douglas, Ed.; And Others

This book presents theoretical studies and national experiences of how education might respond to war, natural catastrophes, or disease, thereby making people more aware and successful at managing difficult situations. The volume's 15 authors, drawn from many parts of the world, deal with human rights (especially those of women, children,…

A New Context Affording for Regulation: The Case of Musical Play

ERIC Educational Resources Information Center

Zachariou, Antonia; Whitebread, David

2017-01-01

The present study set out to investigate theoretical speculations that regulation and musical play, an initial manifestation of musicality, are directly linked. This study aimed to explore the potential for regulation to occur during musical play and investigate the nature of the regulatory behaviours. Thirty-six children, aged 6 and 8, were…

Age-Related Progressions in Story Structure in Young Children's Narratives

ERIC Educational Resources Information Center

Khan, Kiren S.; Gugiu, Mihaiela R.; Justice, Laura M.; Bowles, Ryan P.; Skibbe, Lori E.; Piasta, Shayne B.

2016-01-01

Purpose: Prior theoretical and empirical work has referenced several broad stages of narrative development, particularly in terms of young children's understanding of story structure. However, there is considerable variation in how story structure has been defined and assessed across these studies. The aims of the present study were threefold: (a)…

Persistence in Distance Education: A Study Case Using Bayesian Network to Understand Retention

ERIC Educational Resources Information Center

Eliasquevici, Marianne Kogut; da Rocha Seruffo, Marcos César; Resque, Sônia Nazaré Fernandes

2017-01-01

This article presents a study on the variables promoting student retention in distance undergraduate courses at Federal University of Pará, aiming to help school managers minimize student attrition and maximize retention until graduation. The theoretical background is based on Rovai's Composite Model and the methodological approach is conditional…

Multimedia Glosses and Their Effect on L2 Text Comprehension and Vocabulary Learning

ERIC Educational Resources Information Center

Yanguas, Inigo

2009-01-01

The present study investigates the effects that different types of multimedia glosses, namely textual, pictorial, and textual + pictorial, have on text comprehension and vocabulary learning when the goal is exclusively comprehension of a computerized text. This study is based on the theoretical framework of attention, which maintains that…

A Comparison of Classification Approaches for Cyberbullying and Traditional Bullying Using Data from Six European Countries

ERIC Educational Resources Information Center

Schultze-Krumbholz, Anja; Göbel, Kristin; Scheithauer, Herbert; Brighi, Antonella; Guarini, Annalisa; Tsorbatzoudis, Haralambos; Barkoukis, Vassilis; Pyzalski, Jacek; Plichta, Piotr; Del Rey, Rosario; Casas, José A.; Thompson, Fran; Smith, Peter K.

2015-01-01

In recently published studies on cyberbullying, students are frequently categorized into distinct (cyber)bully and (cyber)victim clusters based on theoretical assumptions and arbitrary cut-off scores adapted from traditional bullying research. The present study identified involvement classes empirically using latent class analysis (LCA), to…

Evidence for Different Components in Children's Visuospatial Working Memory

ERIC Educational Resources Information Center

Mammarella, Irene C.; Pazzaglia, Francesca; Cornoldi, Cesare

2008-01-01

There are a large number of studies demonstrating that visuospatial working memory (VSWM) involves different subcomponents, but there is no agreement on the identity of these dimensions. The present study attempts to combine different theoretical accounts by measuring VSWM. A battery composed of 13 tests was used to assess working memory and, in…

Coordinating Human Services: A Sociological Study of an Interorganizational Network. Research Series, Number 6.

ERIC Educational Resources Information Center

Benson, J. Kenneth; And Others

Interagency relationships have an important bearing upon the effectiveness with which public services are provided to disadvantaged populations. The present study examines interagency interactions and service delivery to the disadvantaged from both an empirical and a theoretical perspective. The findings may be helpful both in the formulation of…

To Succeed or Not to Succeed: A Critical Review of Issues in Learned Helplessness.

ERIC Educational Resources Information Center

Mark, Sandra Fay

1983-01-01

A critical analysis of theoretical and methodological issues in research on learned helplessness is presented. As studied in achievement settings using achievement tasks, learned helplessness is perceived as maladaptive behavior. It has not been studied as an adaptive response to situational demands. New directions and educational implications are…

Therapist Self-Disclosure and the Therapeutic Relationship: A Phenomenological Study from the Client Perspective

ERIC Educational Resources Information Center

Audet, Cristelle T.; Everall, Robin D.

2010-01-01

Therapist self-disclosure is gaining empirical attention amidst theoretical discourse and ethical debate, particularly with regards to its influence on the therapeutic relationship. This paper presents part of a larger qualitative study that explored client experiences of therapist self-disclosure and specifically focuses on the therapeutic…

Critical Studies on the Ideological Structure of Personality.

ERIC Educational Resources Information Center

Barratt, Barnaby B.; And Others

This document contains four papers about the ideological structure of personality. A proposal for a theoretical and methodological reworking of the life-historical inquiry of personality psychology is presented along with a report of some preliminary studies that employ an intensive life-history approach to a distinct topic within the context of…

Mode Deactivation Therapy (MDT): A Theoretical Case Analysis on a Suicidal Adolescent

ERIC Educational Resources Information Center

Apsche, Jack A.; Siv, Alexander M.

2005-01-01

This case study presents a case study of the effectiveness of Mode deactivation therapy (MDT) (Apsche, Bass, Jennings, Murphy, Hunter, and Siv, 2005) with an adolescent male, with reactive conduct disorder, PTSD and 8 lethal suicide attempts. The youngster was hospitalized four times for suicide attempts, three previous placements in residential…

A Test of an Integrative Model Using Social Factors and Personality Traits: Prediction on the Delinquency of South Korean Youth.

PubMed

Yun, Minwoo; Kim, Eunyoung; Park, Woong-Sub

2017-08-01

To more fully comprehend juvenile delinquency, it is necessary to take an integrative approach, with consideration of both personality traits of social risk factors. Many scholars argue the necessity and strength of integrative approach on the ground that juvenile delinquency is an outcome of interplay of individual and social factors. The present study examines the general applicability of an integrative model of personal traits and social risk factors to youth delinquency in the South Korean context. The empirical results show that the delinquency predictors in the current South Korean sample are closely aligned to Loeber and Farrington's theoretical propositions and that found in Western nations. Perhaps this is because South Korea has undergone rapid Westernization for the last decades. Because the correlates in this sample and Western theoretical propositions and studies overlap, an integrative model of personality trait and social risk factors is indeed generally applicable to South Korea. This finding also depicts the extent of Westernization in the South Korean society at least among adolescents. Limitations of the present study and directions for the future study are discussed.

Fragmentation of mercury compounds under ultraviolet light irradiation

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

Kokkonen, E.; Hautala, L.; Jänkälä, K.

2015-08-21

Ultraviolet light induced photofragmentation of mercury compounds is studied experimentally with electron energy resolved photoelectron-photoion coincidence techniques and theoretically with computational quantum chemical methods. A high resolution photoelectron spectrum using synchrotron radiation is presented. Fragmentation of the molecule is studied subsequent to ionization to the atomic-mercury-like d orbitals. State dependent fragmentation behaviour is presented and specific reactions for dissociation pathways are given. The fragmentation is found to differ distinctly in similar orbitals of different mercury compounds.

Simulation studies of the application of SEASAT data in weather and state of sea forecasting models

NASA Technical Reports Server (NTRS)

Cardone, V. J.; Greenwood, J. A.

1979-01-01

The design and analysis of SEASAT simulation studies in which the error structure of conventional analyses and forecasts is modeled realistically are presented. The development and computer implementation of a global spectral ocean wave model is described. The design of algorithms for the assimilation of theoretical wind data into computers and for the utilization of real wind data and wave height data in a coupled computer system are presented.

A Theoretically Based Behavioral Nutrition Intervention for Community Elders at High Risk: The B-NICE Randomized Controlled Clinical Trial

PubMed Central

LOCHER, JULIE L.; BALES, CONNIE W.; ELLIS, AMY C.; LAWRENCE, JEANNINE C.; NEWTON, LAURA; RITCHIE, CHRISTINE S.; ROTH, DAVID L.; BUYS, DAVID L.; VICKERS, KRISTIN S.

2012-01-01

We conducted a study designed to evaluate the efficacy and feasibility of a multilevel self-management intervention to improve nutritional intake in a group of older adults receiving Medicare home health services who were at especially high risk for experiencing undernutrition. The Behavioral Nutrition Intervention for Community Elders (B-NICE) trial used a prospective randomized controlled design to determine whether individually tailored counseling focused on social and behavioral aspects of eating resulted in increased caloric intake and improved nutrition-related health outcomes in a high-risk population of older adults. The study was guided by the theoretical approaches of the Ecological Model and Social Cognitive Theory. The development and implementation of the B-NICE protocol, including the theoretical framework, methodology, specific elements of the behavioral intervention, and assurances of the treatment fidelity, as well as the health policy implications of the trial results, are presented in this article. PMID:22098180

Theoretical aspects of studies of oxide and semiconductor surfaces using low energy positrons

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Maddox, W. B.; Weiss, A. H.

2011-01-01

This paper presents the results of a theoretical study of positron surface and bulk states and annihilation characteristics of surface trapped positrons at the oxidized Cu(100) single crystal and at both As- and Ga-rich reconstructed GaAs(100) surfaces. The variations in atomic structure and chemical composition of the topmost layers of the surfaces associated with oxidation and reconstructions and the charge redistribution at the surfaces are found to affect localization and spatial extent of the positron surface-state wave functions. The computed positron binding energy, work function, and annihilation characteristics reveal their sensitivity to charge transfer effects, atomic structure and chemical composition of the topmost layers of the surfaces. Theoretical positron annihilation probabilities with relevant core electrons computed for the oxidized Cu(100) surface and the As- and Ga-rich reconstructed GaAs(100) surfaces are compared with experimental ones estimated from the positron annihilation induced Auger peak intensities measured from these surfaces.

Game Theoretic Resolution of Water Conflicts

NASA Astrophysics Data System (ADS)

Tyagi, H.; Gosain, A. K.; Khosa, R.

2017-12-01

Water disputes are of multi-disciplinary nature and involve an array of natural, hydrological,social, political and economic issues. Operations Research based decision making methodshave been found to facilitate mathematical analysis of such multifaceted problems thatconsist of multiple stakeholders and their conflicting objectives. Game Theoretic techniqueslike Metagame and Hypergame Analysis can provide a framework for conceptualizing waterconflicts and envisaging their potential solutions. In the present research, firstly a Metagamemodel has been developed to identify range of plausible equilibrium outcomes for resolvingconflicts pertaining to water apportionments in a transboundary watercourse. Further, it hasbeen observed that the contenders often hide their strategies from other players to getfavorable water allocations. Consequently, there are widespread misinterpretations about thetactics of the competitors and contenders have to formulate their strategies entirely based ontheir perception about others. Accordingly, a Hypergame study has also been conducted tomodel the probable misperceptions that may exist amongst the river riparians. Thus, thecurrent study assesses the efficacy of Game Theoretic techniques as possible redressalmechanism for water conflicts.

Experimental and computational study on molecular structure and vibrational analysis of an antihyperglycemic biomolecule: Gliclazide

NASA Astrophysics Data System (ADS)

Karakaya, Mustafa; Kürekçi, Mehmet; Eskiyurt, Buse; Sert, Yusuf; Çırak, Çağrı

2015-01-01

In present study, the experimental and theoretical harmonic vibrational frequencies of gliclazide molecule have been investigated. The experimental FT-IR (400-4000 cm-1) and Laser-Raman spectra (100-4000 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths and bond angles) have been calculated using ab initio Hartree Fock (HF), density functional theory (B3LYP hybrid function) methods with 6-311++G(d,p) and 6-31G(d,p) basis sets by Gaussian 09W program. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. Theoretical optimized geometric parameters and vibrational frequencies have been compared with the corresponding experimental data, and they have been shown to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies have been found.

Experimental and computational study on molecular structure and vibrational analysis of a modified biomolecule: 5-Bromo-2'-deoxyuridine

NASA Astrophysics Data System (ADS)

Çırak, Çağrı; Sert, Yusuf; Ucun, Fatih

In the present study, the experimental and theoretical vibrational spectra of 5-bromo-2'-deoxyuridine were investigated. The experimental FT-IR (400-4000 cm-1) and μ-Raman spectra (100-4000 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths and bond angles) were calculated using ab initio Hartree Fock (HF) and density functional B3LYP method with 6-31G(d), 6-31G(d,p), 6-311++G(d) and 6-311++G(d,p) basis sets by Gaussian program, for the first time. The assignments of vibrational frequencies were performed by potential energy distribution by using VEDA 4 program. The optimized geometric parameters and theoretical vibrational frequencies are compared with the corresponding experimental data and they were seen to be in a good agreement with the each other. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were found.

Experimental and computational study on molecular structure and vibrational analysis of an antihyperglycemic biomolecule: gliclazide.

PubMed

Karakaya, Mustafa; Kürekçi, Mehmet; Eskiyurt, Buse; Sert, Yusuf; Çırak, Çağrı

2015-01-25

In present study, the experimental and theoretical harmonic vibrational frequencies of gliclazide molecule have been investigated. The experimental FT-IR (400-4000 cm(-1)) and Laser-Raman spectra (100-4000 cm(-1)) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths and bond angles) have been calculated using ab initio Hartree Fock (HF), density functional theory (B3LYP hybrid function) methods with 6-311++G(d,p) and 6-31G(d,p) basis sets by Gaussian 09W program. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. Theoretical optimized geometric parameters and vibrational frequencies have been compared with the corresponding experimental data, and they have been shown to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies have been found. Copyright © 2014 Elsevier B.V. All rights reserved.

A theoretical approach to sound propagation and radiation for ducts with suppressors

NASA Technical Reports Server (NTRS)

Rice, E. J.; Sawdy, D. T.

1981-01-01

The several phenomena involved in theoretical prediction of the far-field sound radiation attenuation from an acoustically lined duct were studied. These include absorption by the suppressor, termination reflections, and far-field radiation. Extensive parametric studies show that the suppressor absorption performance can be correlated with mode cut-off ratio or angle of propagation. The other phenomena can be shown to depend explicitly upon mode cut-off ratio. A complete system can thus be generated which can be used to evaluate aircraft sound suppressors and which can be related to the sound source through the cut-off ratio-acoustic power distribution. Although the method is most fully developed for inlet suppressors, several aft radiated noise phenomena are also discussed. This simplified suppressor design and evaluation method is summarized, the recent improvements in the technique are presented, and areas where further refinement is necessary are discussed. Noise suppressor data from engine experiments are compared with the theoretical calculations.

Investigation of numerical simulation on all-optical flip-flop stability maps of 1550nm vertical-cavity surface-emitting laser

NASA Astrophysics Data System (ADS)

Li, Jun; Xia, Qing; Wang, Xiaofa

2017-10-01

Based on the extended spin-flip model, the all-optical flip-flop stability maps of the 1550nm vertical-cavity surface-emitting laser have been studied. Theoretical results show that excellent agreement is found between theoretical and the reported experimental results in polarization switching point current which is equal to 1.95 times threshold. Furthermore, the polarization bistable region is wide which is from 1.05 to 1.95 times threshold. A new method is presented that uses power difference between two linear polarization modes as the judging criterion of trigger degree and stability maps of all-optical flip-flop operation under different injection parameters are obtained. By alternately injecting set and reset pulse with appropriate parameters, the mutual conversion switching between two polarization modes is realized, the feasibility of all-optical flip-flop operation is checked theoretically. The results show certain guiding significance on the experimental study on all optical buffer technology.

Patient perceptions of patient-centred care: empirical test of a theoretical model.

PubMed

Rathert, Cheryl; Williams, Eric S; McCaughey, Deirdre; Ishqaidef, Ghadir

2015-04-01

Patient perception measures are gaining increasing interest among scholars and practitioners. The aim of this study was to empirically examine a conceptual model of patient-centred care using patient perception survey data. Patient-centred care is one of the Institute of Medicine's objectives for improving health care in the 21st century. Patient interviews conducted by the Picker Institute/Commonwealth Fund in the 1980s resulted in a theoretical model and survey questions with dimensions and attributes patients defined as patient-centered. The present study used survey data from patients with overnight visits at 142 U.S. hospitals. Regression analysis found significant support for the theoretical model. Perceptions of emotional support had the strongest relationship with overall care ratings. Coordination of care, and physical comfort were strongly related as well. Understanding how patients experience their care can help improve understanding of what patients believe is patient-centred, and of how care processes relate to important patient outcomes. © 2012 John Wiley & Sons Ltd.

Magnetic properties of Ruddlesden-Popper phases Sr3 -xYx(Fe1.25Ni0.75) O7 -δ : A combined experimental and theoretical investigation

NASA Astrophysics Data System (ADS)

Keshavarz, Samara; Kontos, Sofia; Wardecki, Dariusz; Kvashnin, Yaroslav O.; Pereiro, Manuel; Panda, Swarup K.; Sanyal, Biplab; Eriksson, Olle; Grins, Jekabs; Svensson, Gunnar; Gunnarsson, Klas; Svedlindh, Peter

2018-04-01

We present a comprehensive study of the magnetic properties of Sr3 -xYx(Fe1.25Ni0.75) O7 -δ (0 ≤x ≤0.75 ). Experimentally, the magnetic properties are investigated using superconducting quantum interference device (SQUID) magnetometry and neutron powder diffraction (NPD). This is complemented by a theoretical study based on density functional theory as well as the Heisenberg exchange parameters. Experimental results show an increase in the Néel temperature (TN) with an increase of Y concentrations and O occupancy. The NPD data reveal that all samples are antiferromagnetically ordered at low temperatures, which has been confirmed by our theoretical simulations for the selected samples. Our first-principles calculations suggest that the three-dimensional magnetic order is stabilized due to finite interlayer exchange couplings. The latter give rise to finite interlayer spin-spin correlations, which disappear above TN.

Perceptual awareness and its neural basis: bridging experimental and theoretical paradigms

PubMed Central

Raffone, Antonino; Srinivasan, Narayanan; van Leeuwen, Cees

2014-01-01

Understanding consciousness is a major scientific challenge of our times, and perceptual awareness is an integral part of that challenge. This Theme Issue aims to provide a timely focus on crucial insights from leading scientists on perceptual awareness and its neural basis. The issue refers to key research questions and findings in perceptual awareness research and aims to be a catalyst for further research, by bringing together the state-of-the-art. It shows how bridges are being built between empirical and theoretical research and proposes new directions for the study of multisensory awareness and the role of the states of the body therein. In this introduction, we highlight crucial problems that have characterized the development of the study of perceptual awareness. We then provide an overview of major experimental and theoretical paradigms related to perceptual awareness and its neural basis. Finally, we present an overview of the Theme Issue, with reference to the contributed articles and their relationships. PMID:24639576

Theoretical and experimental study of fenofibrate and simvastatin

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Building child trauma theory from longitudinal studies: a meta-analysis.

PubMed

Alisic, Eva; Jongmans, Marian J; van Wesel, Floryt; Kleber, Rolf J

2011-07-01

Many children are exposed to traumatic events, with potentially serious psychological and developmental consequences. Therefore, understanding development of long-term posttraumatic stress in children is essential. We aimed to contribute to child trauma theory by focusing on theory use and theory validation in longitudinal studies. Forty studies measuring short-term predictors and long-term posttraumatic stress symptoms were identified and coded for theoretical grounding, sample characteristics, and correlational effect sizes. Explicit theoretical frameworks were present in a minority of the studies. Important predictors of long-term posttraumatic stress were symptoms of acute and short-term posttraumatic stress, depression, anxiety, and parental posttraumatic stress. Female gender, injury severity, duration of hospitalization, and elevated heart rate shortly after hospitalization yielded small effect sizes. Age, minority status, and socioeconomic status were not significantly related to long-term posttraumatic stress reactions. Since many other variables were not studied frequently enough to compute effect sizes, existing theoretical frameworks could only be partially confirmed or falsified. Child trauma theory-building can be facilitated by development of encouraging journal policies, the use of comparable methods, and more intense collaboration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Structural transformation during Li/Na insertion and theoretical cyclic voltammetry of the δ-NH4V4O10 electrode: a first-principles study.

PubMed

Sarkar, Tanmay; Kumar, Parveen; Bharadwaj, Mridula Dixit; Waghmare, Umesh

2016-04-14

A double layer δ-NH4V4O10, due to its high energy storage capacity and excellent rate capability, is a very promising cathode material for Li-ion and Na-ion batteries for large-scale renewable energy storage in transportation and smart grids. While it possesses better stability, and higher ionic and electronic conductivity than the most widely explored V2O5, the mechanisms of its cyclability are yet to be understood. Here, we present a theoretical cyclic voltammetry as a tool based on first-principles calculations, and uncover structural transformations that occur during Li(+)/Na(+) insertion (x) into (Lix/Nax)NH4V4O10. Structural distortions associated with single-phase and multi-phase structural changes during the insertion of Li(+)/Na(+), identified through the analysis of voltage profile and theoretical cyclic voltammetry are in agreement with the reported experimental electrochemical measurements on δ-NH4V4O10. We obtain an insight into its electronic structure with a lower band gap that is responsible for the high rate capability of (Lix/Nax) δ-NH4V4O10. The scheme of theoretical cyclic voltammetry presented here will be useful for addressing issues of cyclability and energy rate in other electrode materials.

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: theoretical systematics and Baryon Acoustic Oscillations in the galaxy correlation function

NASA Astrophysics Data System (ADS)

Vargas-Magaña, Mariana; Ho, Shirley; Cuesta, Antonio J.; O'Connell, Ross; Ross, Ashley J.; Eisenstein, Daniel J.; Percival, Will J.; Grieb, Jan Niklas; Sánchez, Ariel G.; Tinker, Jeremy L.; Tojeiro, Rita; Beutler, Florian; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Prada, Francisco; Rodríguez-Torres, Sergio A.; Rossi, Graziano; Seo, Hee-Jong; Brownstein, Joel R.; Olmstead, Matthew; Thomas, Daniel

2018-06-01

We investigate the potential sources of theoretical systematics in the anisotropic Baryon Acoustic Oscillation (BAO) distance scale measurements from the clustering of galaxies in configuration space using the final Data Release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS). We perform a detailed study of the impact on BAO measurements from choices in the methodology such as fiducial cosmology, clustering estimators, random catalogues, fitting templates, and covariance matrices. The theoretical systematic uncertainties in BAO parameters are found to be 0.002 in the isotropic dilation α and 0.003 in the quadrupolar dilation ɛ. The leading source of systematic uncertainty is related to the reconstruction techniques. Theoretical uncertainties are sub-dominant compared with the statistical uncertainties for BOSS survey, accounting 0.2σstat for α and 0.25σstat for ɛ (σα, stat ˜ 0.010 and σɛ, stat ˜ 0.012, respectively). We also present BAO-only distance scale constraints from the anisotropic analysis of the correlation function. Our constraints on the angular diameter distance DA(z) and the Hubble parameter H(z), including both statistical and theoretical systematic uncertainties, are 1.5 per cent and 2.8 per cent at zeff = 0.38, 1.4 per cent and 2.4 per cent at zeff = 0.51, and 1.7 per cent and 2.6 per cent at zeff = 0.61. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are cross-checked with other BAO analysis in Alam et al. The systematic error budget concerning the methodology on post-reconstruction BAO analysis presented here is used in Alam et al. to produce the final cosmological constraints from BOSS.

The Nature and Meaning of Body Concepts in Everyday Language and Theoretical Discourse.

PubMed

Pollio, Howard R; Finn, Mike; Custer, Morgun

2016-06-01

Within phenomenological philosophy four topics, (1) Body, (2) Time, (3) Others and the Social Order and (4) World serve as the major contexts in which human perception, action and reflection take place. At present only three of these domains have been studied from an empirical perspective, leaving Body as the one domain requiring further analysis. Given this state of affairs, the purpose of the present study is to determine the everyday and theoretical meanings of body. To accomplish this task participants coded randomly selected body- related words into groups on the basis of having similar meanings. Once these groupings were established they were then evaluated by statistical clustering and multidimensional scaling procedures. Results indicated that it was possible to define the everyday meaning of the human experience of the human body in terms of the following set of themes: (1) inside/outside, (2) visible/not visible, (3) vitality and activity, (4) instrument and object and (5) appearance and self-expression. Concerns about the representativeness of the words studied led to the development and use of individual word pools from which a set of 50 partially different words was randomly selected for each participant. Results indicated little difference between themes produced in the present study when compared with those of an earlier study. The specific themes derived from the present study were then related to embodiment issues as reflected in the philosophical writings of Merleau-Ponty, the psycholinguistic analyses of Lakoff and Johnson and experimental psychology.

New aspects of the antioxidant properties of phenolic acids: a combined theoretical and experimental approach.

PubMed

Anouar, E; Kosinová, P; Kozlowski, D; Mokrini, R; Duroux, J L; Trouillas, P

2009-09-21

Ferulic acid is widely distributed in the leaves and seeds of cereals as well as in coffee, apples, artichokes, peanuts, oranges and pineapples. Like numerous other natural polyphenols it exhibits antioxidant properties. It is known to act as a free radical scavenger by H atom transfer from the phenolic OH group. In the present joint experimental and theoretical studies we studied a new mechanism to explain such activities. Ferulic acid can indeed act by radical addition on the alpha,beta-double bond. On the basis of the identification of metabolites formed in an oxidative radiolytic solution and after DFT calculations, we studied the thermodynamic and kinetic aspects of this reaction. Addition and HAT reactions were treated as competitive reactions. The possibility of dimer formation was also investigated from a theoretical point of view; the high barriers we obtained contribute to explaining why we did not observe those compounds as major radiolytic compounds. The DPPH free radical scavenging capacity of ferulic acid and the oxidative products was measured and is discussed on the basis of DFT calculations (BDEs and spin densities).

The anharmonic quartic force field infrared spectra of three polycyclic aromatic hydrocarbons: Naphthalene, anthracene, and tetracene.

PubMed

Mackie, Cameron J; Candian, Alessandra; Huang, Xinchuan; Maltseva, Elena; Petrignani, Annemieke; Oomens, Jos; Buma, Wybren Jan; Lee, Timothy J; Tielens, Alexander G G M

2015-12-14

Current efforts to characterize and study interstellar polycyclic aromatic hydrocarbons (PAHs) rely heavily on theoretically predicted infrared (IR) spectra. Generally, such studies use the scaled harmonic frequencies for band positions and double harmonic approximation for intensities of species, and then compare these calculated spectra with experimental spectra obtained under matrix isolation conditions. High-resolution gas-phase experimental spectroscopic studies have recently revealed that the double harmonic approximation is not sufficient for reliable spectra prediction. In this paper, we present the anharmonic theoretical spectra of three PAHs: naphthalene, anthracene, and tetracene, computed with a locally modified version of the SPECTRO program using Cartesian derivatives transformed from Gaussian 09 normal coordinate force constants. Proper treatments of Fermi resonances lead to an impressive improvement on the agreement between the observed and theoretical spectra, especially in the C-H stretching region. All major IR absorption features in the full-scale matrix-isolated spectra, the high-temperature gas-phase spectra, and the most recent high-resolution gas-phase spectra obtained under supersonically cooled molecular beam conditions in the CH-stretching region are assigned.

The anharmonic quartic force field infrared spectra of three polycyclic aromatic hydrocarbons: Naphthalene, anthracene, and tetracene

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

Mackie, Cameron J., E-mail: mackie@strw.leidenuniv.nl; Candian, Alessandra; Tielens, Alexander G. G. M.

2015-12-14

Current efforts to characterize and study interstellar polycyclic aromatic hydrocarbons (PAHs) rely heavily on theoretically predicted infrared (IR) spectra. Generally, such studies use the scaled harmonic frequencies for band positions and double harmonic approximation for intensities of species, and then compare these calculated spectra with experimental spectra obtained under matrix isolation conditions. High-resolution gas-phase experimental spectroscopic studies have recently revealed that the double harmonic approximation is not sufficient for reliable spectra prediction. In this paper, we present the anharmonic theoretical spectra of three PAHs: naphthalene, anthracene, and tetracene, computed with a locally modified version of the SPECTRO program using Cartesianmore » derivatives transformed from Gaussian 09 normal coordinate force constants. Proper treatments of Fermi resonances lead to an impressive improvement on the agreement between the observed and theoretical spectra, especially in the C–H stretching region. All major IR absorption features in the full-scale matrix-isolated spectra, the high-temperature gas-phase spectra, and the most recent high-resolution gas-phase spectra obtained under supersonically cooled molecular beam conditions in the CH-stretching region are assigned.« less

Identification of multiple intelligences for high school students in theoretical and applied science courses

NASA Astrophysics Data System (ADS)

Wiseman, D. Kim

Historically educators in the United States have used the Stanford-Binet intelligence test to measure a students' ability in logical/mathematical and linguistic domains. This measurement is being used by a society that has evolved from agrarian and industrial-based economies to what is presently labeled a technological society. As society has changed so have the educational needs of the students who will live in this technological society. This study assessed the multiple intelligences of high school students enrolled in theoretical and applied science (physics and applied physics) courses. Studies have verified that performance and outcomes of students enrolled in these courses are similar in standardized testing but instructional methodology and processes are dissimilar. Analysis of multiple intelligence profiles collected from this study found significant differences in logical/mathematical, bodily/kinesthetic and intrapersonal multiple intelligences of students in theoretical science courses compared to students in applied science courses. Those differences clearly illustrate why it is imperative for educators to expand the definition of intelligence for students entering the new millennium.

Factors Influencing the Use of Learning Management System in Saudi Arabian Higher Education: A Theoretical Framework

ERIC Educational Resources Information Center

Asiri, Mohammed J. Sherbib; Mahmud, Rosnaini bt; Bakar, Kamariah Abu; Ayub, Ahmad Fauzi bin Mohd

2012-01-01

The purpose of this paper is to present the theoretical framework underlying a research on factors that influence utilization of the Jusur Learning Management System (Jusur LMS) in Saudi Arabian public universities. Development of the theoretical framework was done based on library research approach. Initially, the existing literature relevant to…

What Are the Differences between Happiness and Self-Esteem

ERIC Educational Resources Information Center

Lyubomirsky, Sonja; Tkach, Chris; DiMatteo, Robin M.

2006-01-01

The present study investigated theoretically and empirically derived similarities and differences between the constructs of enduring happiness and self-esteem. Participants (N = 621), retired employees ages 51-95, completed standardized measures of affect, personality, psychosocial characteristics, physical health, and demographics. The relations…

Reference Assessment

ERIC Educational Resources Information Center

Bivens-Tatum, Wayne

2006-01-01

This article presents interesting articles that explore several different areas of reference assessment, including practical case studies and theoretical articles that address a range of issues such as librarian behavior, patron satisfaction, virtual reference, or evaluation design. They include: (1) "Evaluating the Quality of a Chat Service"…

Deliverology

ERIC Educational Resources Information Center

Nordstrum, Lee E.; LeMahieu, Paul G.; Dodd, Karen

2017-01-01

Purpose: This paper is one of seven in this volume elaborating different approaches to quality improvement in education. This paper aims to delineate a methodology called Deliverology. Design/methodology/approach: The paper presents the origins, theoretical foundations, core principles and a case study showing an application of Deliverology in the…

Psychosocial Research and the Hospitalized Adolescent: Approaches and Challenges.

ERIC Educational Resources Information Center

Denholm, Carey J.; Joschko, Michael

1988-01-01

Notes that hospitalized adolescents are often participants in psychosocial research. Presents examples of studies within four approaches (instructional, theoretical, informational, experimental) to describe behaviors of hospitalized adolescents. Discusses impact of various illness states (acute, chronic, terminal) and readiness of adolescent to be…

M dwarfs: Theoretical work

NASA Technical Reports Server (NTRS)

Mullan, Dermott J.

1987-01-01

Theoretical work on the atmospheres of M dwarfs has progressed along lines parallel to those followed in the study of other classes of stars. Such models have become increasingly sophisticated as improvements in opacities, in the equation of state, and in the treatment of convection were incorporated during the last 15 to 20 years. As a result, spectrophotometric data on M dwarfs can now be fitted rather well by current models. The various attempts at modeling M dwarf photospheres in purely thermal terms are summarized. Some extensions of these models to include the effects of microturbulence and magnetic inhomogeneities are presented.

Theoretical study of ferroelectric nanoparticles using phase reconstructed electron microscopy

NASA Astrophysics Data System (ADS)

Phatak, C.; Petford-Long, A. K.; Beleggia, M.; De Graef, M.

2014-06-01

Ferroelectric nanostructures are important for a variety of applications in electronic and electro-optical devices, including nonvolatile memories and thin-film capacitors. These applications involve stability and switching of polarization using external stimuli, such as electric fields. We present a theoretical model describing how the shape of a nanoparticle affects its polarization in the absence of screening charges, and quantify the electron-optical phase shift for detecting ferroelectric signals with phase-sensitive techniques in a transmission electron microscope. We provide an example phase shift computation for a uniformly polarized prolate ellipsoid with varying aspect ratio in the absence of screening charges.

A structural and theoretical study of the alkylammonium nitrates forefather: Liquid methylammonium nitrate

NASA Astrophysics Data System (ADS)

Gontrani, Lorenzo; Caminiti, Ruggero; Salma, Umme; Campetella, Marco

2017-09-01

We present here a structural and vibrational analysis of melted methylammonium nitrate, the simplest compound of the family of alkylammonium nitrates. The static and dynamical features calculated were endorsed by comparing the experimental X-ray data with the theoretical ones. A reliable description cannot be obtained with classical molecular dynamics owing to polarization effects. Contrariwise, the structure factor and the vibrational frequencies obtained from ab initio molecular dynamics trajectories are in very good agreement with the experiment. A careful analysis has provided additional information on the complex hydrogen bonding network that exists in this liquid.

Application Of Numerical Modelling To Ribbed Wire Rod Dimensions Precision Increase

NASA Astrophysics Data System (ADS)

Szota, Piotr; Mróz, Sebastian; Stefanik, Andrzej

2007-05-01

The paper presents the results of theoretical and experimental investigations of the process of rolling square ribbed wire rod designed for concrete reinforcement. Numerical modelling of the process of rolling in the finishing and pre-finishing grooves was carried out using the Forge2005® software. In the investigation, particular consideration was given to the analysis of the effect of pre-finished band shape on the formation of ribs on the finished wire rod in the finishing groove. The results of theoretical studies were verified in experimental tests, which were carried out in a wire rolling mill.

Nuclear clustering and the electron screening puzzle

NASA Astrophysics Data System (ADS)

Bertulani, C. A.; Spitaleri, C.

2018-01-01

Electron screening changes appreciably the magnitude of astrophysical nuclear reactions within stars. This effect is also observed in laboratory experiments on Earth, where atomic electrons are present in the nuclear targets. Theoretical models were developed over the past 30 years and experimental measurements have been carried out to study electron screening in thermonuclear reactions. None of the theoretical models were able to explain the high values of the experimentally determined screening potentials. We explore the possibility that the "electron screening puzzle" is due to nuclear clusterization and polarization e_ects in the fusion reactions. We will discuss the supporting arguments for this scenario.

Theory of the Trojan-Horse Method - From the Original Idea to Actual Applications

NASA Astrophysics Data System (ADS)

Typel, Stefan

2018-01-01

The origin and the main features of the Trojan-horse (TH) method are delineated starting with the original idea of Gerhard Baur. Basic theoretical considerations, general experimental conditions and possible problems are discussed. Significant steps in experimental studies towards the implementation of the TH method and the development of the theoretical description are presented. This lead to the successful application of the TH approach by Claudio Spitaleri and his group to determine low-energy cross section that are relevant for astrophysics. An outlook with possible developments in the future are given.

Aortic stiffness improves the prediction of both diagnosis and severity of coronary artery disease.

PubMed

Yannoutsos, Alexandra; Ahouah, Mathieu; Dreyfuss Tubiana, Céline; Topouchian, Jirar; Safar, Michel E; Blacher, Jacques

2018-02-01

Elective coronography has low diagnostic yield for obstructive coronary artery disease (CAD). We aim to determine whether non-invasive aortic stiffness assessment improves diagnostic accuracy of CAD screening by reducing the number of false-positive results from the cardiac stress test. A cross-sectional study was conducted from January 2013 to September 2014 in our medical center. Electrocardiogram (ECG) stress test coupled with nuclear imaging was performed in 367 consecutive patients routinely followed for myocardial ischemia screening. Aortic pulse wave velocity (PWV) was assessed by applanation tonometry in the overall population. Forty-two patients underwent elective coronography because of ischemia. Theoretical PWV was calculated according to age, blood pressure and gender. The results were expressed as an index ((measured PWV-theoretical PWV)/theoretical PWV) for each patient. Ten patients presented with obstructive CAD, 16 patients had non-obstructive CAD and 16 patients had normal coronary angiography. PWV index and severity of CAD were positively correlated (P=0.001). All patients with obstructive CAD had a positive PWV index. When considering the PWV index retrospectively, the false positive results of cardiac stress test were significantly reduced (P<0.001). Twenty-three procedures may have been avoided in the present study cohort. The salient finding of this study was that in patients with known or suspected CAD, routinely followed aortic PWV index may be considered clinically useful for reducing the rate of unnecessary invasive angiographies. The clinical relevance of this individualized decision approach should be confirmed in a large-scale study. Prospective studies have the potential to evaluate the PWV index as a marker of CAD.

A theoretical study of a laminar diffusion flame

NASA Technical Reports Server (NTRS)

Frair, K. L.

1978-01-01

Theoretical models of an axisymmetric laminar diffusion flame are discussed, with an emphasis on the behavior of such flames at increasing pressures. The flame-sheet or Burke-Schumann model (in terms of Bessel functions) and various boundary layer numerical solutions are presented and their results compared with experimental data. The most promising theoretical model combines the numerical flow field solution of the Patankar-Spalding computer code with the Pratt-Wormeck chemical reaction subroutine. The flame shapes for pressures of 1, 5, 10, 20, and 50 atmospheres were computed and agree remarkably well with experimental data. There is a noticeable shape change with pressure, believed to be a result of buoyancy effects. The chemical concentration profiles do not exhibit much dependence on pressure, a reflection of the fact that only one chemical mechanism was utilized at all pressures.

Gauge interactions theory and experiment

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

Zichichi, A.

This volume brings together physicists from around the world to report and discuss the exciting advances made recently in theoretical and experimental aspects of gauge interactions. Following a presentation of the theoretical foundations of and recent developments in gauge fields, the contrib utors fogus on supersymmetry, the derivation of Higgs particles from gauge fields, and heavy leptons. Other chapters discuss the use of quantum chromodynamics in describing basic interactions among quarks and gluons, in predicting the existence of glueballs, and in application to heavy flavor production in strong interactions. The editor, Antonino Zichichi, provides a study of the multiparticle hadronicmore » systems produced in highenergy soft (pp) interactions. Other interesting chapters deal with photon scattering at very high energies and theoretical alternatives to the electroweak model, and the volume concludes with proposals for future experimental facilities for European physics.« less

Insights into the Hydrogen-Atom Transfer of the Blue Aroxyl.

PubMed

Bächle, Josua; Marković, Marijana; Kelterer, Anne-Marie; Grampp, Günter

2017-10-19

An experimental and theoretical study on hydrogen-atom transfer dynamics in the hydrogen-bonded substituted phenol/phenoxyl complex of the blue aroxyl (2,4,6-tri-tert-butylphenoxyl) is presented. The experimental exchange dynamics is determined in different organic solvents from the temperature-dependent alternating line-width effect in the continuous-wave ESR spectrum. From bent Arrhenius plots, effective tunnelling contributions with parallel heavy-atom motion are concluded. To clarify the transfer mechanism, reaction paths for different conformers of the substituted phenol/phenoxyl complex are modelled theoretically. Various DFT and post-Hartree-Fock methods including multireference methods are applied. From the comparison of experimental and theoretical data it is concluded that the system favours concerted hydrogen-atom transfer along a parabolic reaction path caused by heavy-atom motion. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Introduction to the focus issue: fifty years of chaos: applied and theoretical.

PubMed

Hikihara, Takashi; Holmes, Philip; Kambe, Tsutomu; Rega, Giuseppe

2012-12-01

The discovery of deterministic chaos in the late nineteenth century, its subsequent study, and the development of mathematical and computational methods for its analysis have substantially influenced the sciences. Chaos is, however, only one phenomenon in the larger area of dynamical systems theory. This Focus Issue collects 13 papers, from authors and research groups representing the mathematical, physical, and biological sciences, that were presented at a symposium held at Kyoto University from November 28 to December 2, 2011. The symposium, sponsored by the International Union of Theoretical and Applied Mechanics, was called 50 Years of Chaos: Applied and Theoretical. Following some historical remarks to provide a background for the last 50 years, and for chaos, this Introduction surveys the papers and identifies some common themes that appear in them and in the theory of dynamical systems.

Water-equivalence of gel dosimeters for radiology medical imaging.

PubMed

Valente, M; Vedelago, J; Chacón, D; Mattea, F; Velásquez, J; Pérez, P

2018-03-08

International dosimetry protocols are based on determinations of absorbed dose to water. Ideally, the phantom material should be water equivalent; that is, it should have the same absorption and scatter properties as water. This study presents theoretical, experimental and Monte Carlo modeling of water-equivalence of Fricke and polymer (NIPAM, PAGAT and itaconic acid ITABIS) gel dosimeters. Mass and electronic densities along with effective atomic number were calculated by means of theoretical approaches. Samples were scanned by standard computed tomography. Photon mass attenuation coefficients and electron stopping powers were examined. Theoretical, Monte Carlo and experimental results confirmed good water-equivalence for all gel dosimeters. Overall variations with respect to water in the low energy radiology range (up to 130 kVp) were found to be less than 3% in average. Copyright © 2018 Elsevier Ltd. All rights reserved.

Amplitude-dependent internal friction, hysteretic nonlinearity, and nonlinear oscillations in a magnesite resonator.

PubMed

Nazarov, V E; Kolpakov, A B; Radostin, A V

2012-07-01

The results of experimental and theoretical studies of low-frequency nonlinear acoustics phenomena (amplitude-dependent loss, resonance frequency shifts, and a generation of second and third harmonics) in a magnesite rod resonator are presented. Acceleration and velocity oscillograms of vibrations of the free boundary of the resonator caused by harmonic excitations were measured and analyzed. A theoretical description of the observed amplitude dependences was carried out within the framework of the phenomenological state equations that contain either of the two types of hysteretic nonlinearity (elastic and inelastic). The type of hysteresis and parameters of acoustic nonlinearity of magnesite were established from comparing the experimental measurements with the theoretical dependences. The values of the parameters were anomalously high even when compared to those of other strongly nonlinear polycrystalline materials such as granite, marble, limestone, sandstone, etc.

Number theoretical foundations in cryptography

NASA Astrophysics Data System (ADS)

Atan, Kamel Ariffin Mohd

2017-08-01

In recent times the hazards in relationships among entities in different establishments worldwide have generated exciting developments in cryptography. Central to this is the theory of numbers. This area of mathematics provides very rich source of fundamental materials for constructing secret codes. Some number theoretical concepts that have been very actively used in designing crypto systems will be highlighted in this presentation. This paper will begin with introduction to basic number theoretical concepts which for many years have been thought to have no practical applications. This will include several theoretical assertions that were discovered much earlier in the historical development of number theory. This will be followed by discussion on the "hidden" properties of these assertions that were later exploited by designers of cryptosystems in their quest for developing secret codes. This paper also highlights some earlier and existing cryptosystems and the role played by number theoretical concepts in their constructions. The role played by cryptanalysts in detecting weaknesses in the systems developed by cryptographers concludes this presentation.

Residents' responses to wildland fire programs: a review of cognitive and behavioral studies

Treesearch

James D. Absher; Jerry J. Vaske; Lori B. Shelby

2009-01-01

A compilation and summary of four research studies is presented. They were aimed at developing a theoretical and practical understanding of homeowners’ attitudes and behaviors in the wildland-urban interface (WUI) in relation to the threat from wildland fires. Individual studies focused on models and methods that measured (1) value orientations (patterns of basic...

The Impact of Semantic Impairment on Verbal Short-Term Memory in Stroke Aphasia and Semantic Dementia: A Comparative Study

ERIC Educational Resources Information Center

Jefferies, Elizabeth; Hoffman, Paul; Jones, Roy; Lambon Ralph, Matthew A.

2008-01-01

This study presents the first direct comparison of immediate serial recall in semantic dementia (SD) and transcortical sensory aphasia (TSA). Previous studies of the effect of semantic impairment on verbal short-term memory (STM) have led to important theoretical advances. However, different conclusions have been drawn from these two groups. This…

Higher Education and Employability: A Case Study of Debt and Justice in the Process to Becoming A Work College

ERIC Educational Resources Information Center

Bolger, Andrew T.

2017-01-01

This study presents the findings that emerged in a qualitative policy-oriented case study of an institution's transition to a work college. Using Resource Dependence Theory as the theoretical framework, 32 individual interviews were collected, along with other observational data and institutional archives to understand the appeal of federal policy…

Character in Learning for Life: A Virtue-Ethical Rationale for Recent Research on Moral and Values Education

ERIC Educational Resources Information Center

Arthur, James; Carr, David

2013-01-01

This article has three broad aims. The first is to draw attention what is probably the largest empirical study of moral, values and character education in the United Kingdom to the present date. The second is to outline--sufficient for present purposes--a plausible conceptual or theoretical case for placing a particular virtue-ethical concept of…

The Role of Co-Occurring Disruptive Behavior in the Clinical Presentation of Children and Adolescents with Anxiety in the Context of Autism Spectrum Disorders

ERIC Educational Resources Information Center

Storch, Eric A.; Arnold, Elysse B.; Jones, Anna M.; Ale, Chelsea M.; Wood, Jeffrey J.; Ehrenreich-May, Jill; Lewin, Adam B.; Mutch, P. Jane; Murphy, Tanya K.

2012-01-01

This study explored the impact of disruptive behavior disorder (DBD) comorbidity on theoretically relevant correlates among 87 children and adolescents with autism spectrum disorders (ASD) and clinically significant anxiety. Relative to youth with ASD and anxiety alone, participants with ASD, anxiety, and DBD: (a) presented with significantly more…

Study of Designing BPF by Using LC Tap-Coupling Resonators

NASA Astrophysics Data System (ADS)

Yasuzumi, Takenori; Wada, Kouji; Nakajima, Naoko; Hashimoto, Osamu

The resonance characteristics of short-ended half-wavelength coplanar waveguide(CPW) LC tap-coupling resonators are examined theoretically and experimentally. The characteristics near the passband have been improved by applying the presented CPW resonator to a design of a bandpass filter(BPF). Moreover, the difference between the calculation and the measurement results is examined by using the equivalent circuit about the presented BPF.

Quantum partner-dance in the 12C + 12C system yields sub-Coulomb fusion resonances

NASA Astrophysics Data System (ADS)

Diaz-Torres, Alexis; Wiescher, Michael

2014-03-01

A preliminary study of the 12C + 12C sub-Coulomb fusion reaction using the time-dependent wave-packet method is presented. The theoretical sub-Coulomb fusion resonances seem to correspond well with observations. The present method might be a more suitable tool for expanding the cross-section predictions towards lower energies than the commonly used potential-model approximation.

Study of an instrument for sensing errors in a telescope wavefront

NASA Technical Reports Server (NTRS)

Golden, L. J.; Shack, R. V.; Slater, D. N.

1973-01-01

Partial results are presented of theoretical and experimental investigations of different focal plane sensor configurations for determining the error in a telescope wavefront. The coarse range sensor and fine range sensors are used in the experimentation. The design of a wavefront error simulator is presented along with the Hartmann test, the shearing polarization interferometer, the Zernike test, and the Zernike polarization test.

The Aerodynamic Optimization of Wings at Subsonic Speeds and the Influence of Wingtip Design. Thesis

NASA Technical Reports Server (NTRS)

Zimmer, H.

1987-01-01

Some of the objectives of modern aircraft development are related to the achievement of reduced fuel consumption and aircraft noise. This investigation is mainly concerned with the aerodynamic aspects of aircraft development, i.e., reduction of induced drag. New studies of wing design, and in particular wing tips, are considered. Induced drag is important since, in cruising flight, it accounts for approximately one-third of the entire drag for the aircraft, and one-half while climbing. A survey is presented for the wing geometries and wing tip designs studied, and theoretical investigations of different planar wings with systematically varied wing tip forms are conducted. Attention is also paid to a theoretical study of some planar and nonplanar wings and their comparison with experimental data.

Tracing the Roots of Textbook Study Systems: An Extended Historical Perspective. College Reading and Learning Assistance Technical Report 86-02.

ERIC Educational Resources Information Center

Stahl, Norman A.; Henk, William A.

Francis P. Robinson's 1946 text, "Effective Study," first presented his Survey, Question, Read, Recite, and Review (SQ3R) study system, which is held to be the most widely advocated textbook study system. This paper traces the development of the ideas behind the SQ3R. SQ3R's theoretical foundation began with work in…

The Use of Brain Electrophysiology Techniques To Study Language: A Basic Guide for the Beginning Consumer of Electrophysiology Information.

ERIC Educational Resources Information Center

Molfese, Dennis L.; Molfese, Victoria J.; Kelly, Spencer

2001-01-01

This article provides an introduction to the use of event-related potential (ERP) approaches to study language processes. First, a brief history of the emergence of this technology is presented, followed by definitions, a theoretical overview, and a practical guide to conducting ERP studies. Examples of language studies that use this technique are…

Theoretical DFT study on spectroscopic signature and molecular dynamics of neurotransmitter and effect of hydrogen removal

NASA Astrophysics Data System (ADS)

Mukherjee, V.; Singh, N. P.; Yadav, R. A.

2013-04-01

Vibrational spectroscopic study has been made for the serotonin molecule and its deprotonated form. The Infrared and Raman spectra in optimum geometry of these two molecules are calculated using density functional theorem and the normal modes are assigned using potential energy distributions (PEDs) which are calculated using normal coordinate analysis method. The vibrational frequencies of these two molecules are reported and a comparison has been made. The effect of removal of the hydrogen atom from the serotonin molecule upon its geometry and vibrational frequencies are studied. Electronic structures of these two molecules are also studied using natural bond orbital (NBO) analysis. Theoretical Raman spectrum of serotonin at different exciting laser frequencies and at different temperatures are obtained and the results are discussed. Present study reveals that some wrong assignments had been made for serotonin molecule in earlier study.

Numerical Models for Sound Propagation in Long Spaces

NASA Astrophysics Data System (ADS)

Lai, Chenly Yuen Cheung

Both reverberation time and steady-state sound field are the key elements for assessing the acoustic condition in an enclosed space. They affect the noise propagation, speech intelligibility, clarity index, and definition. Since the sound field in a long space is non diffuse, classical room acoustics theory does not apply in this situation. The ray tracing technique and the image source methods are two common models to fathom both reverberation time and steady-state sound field in long enclosures nowadays. Although both models can give an accurate estimate of reverberation times and steady-state sound field directly or indirectly, they often involve time-consuming calculations. In order to simplify the acoustic consideration, a theoretical formulation has been developed for predicting both steady-state sound fields and reverberation times in street canyons. The prediction model is further developed to predict the steady-state sound field in a long enclosure. Apart from the straight long enclosure, there are other variations such as a cross junction, a long enclosure with a T-intersection, an U-turn long enclosure. In the present study, an theoretical and experimental investigations were conducted to develop formulae for predicting reverberation times and steady-state sound fields in a junction of a street canyon and in a long enclosure with T-intersection. The theoretical models are validated by comparing the numerical predictions with published experimental results. The theoretical results are also compared with precise indoor measurements and large-scale outdoor experimental results. In all of previous acoustical studies related to long enclosure, most of the studies are focused on the monopole sound source. Besides non-directional noise source, many noise sources in long enclosure are dipole like, such as train noise and fan noise. In order to study the characteristics of directional noise sources, a review of available dipole source was conducted. A dipole was constructed which was subsequent used for experimental studies. In additional, a theoretical model was developed for predicting dipole sound fields. The theoretical model can be used to study the effect of a dipole source on the speech intelligibility in long enclosures.

Exploring Environmental Factors in Nursing Workplaces That Promote Psychological Resilience: Constructing a Unified Theoretical Model

PubMed Central

Cusack, Lynette; Smith, Morgan; Hegney, Desley; Rees, Clare S.; Breen, Lauren J.; Witt, Regina R.; Rogers, Cath; Williams, Allison; Cross, Wendy; Cheung, Kin

2016-01-01

Building nurses' resilience to complex and stressful practice environments is necessary to keep skilled nurses in the workplace and ensuring safe patient care. A unified theoretical framework titled Health Services Workplace Environmental Resilience Model (HSWERM), is presented to explain the environmental factors in the workplace that promote nurses' resilience. The framework builds on a previously-published theoretical model of individual resilience, which identified the key constructs of psychological resilience as self-efficacy, coping and mindfulness, but did not examine environmental factors in the workplace that promote nurses' resilience. This unified theoretical framework was developed using a literary synthesis drawing on data from international studies and literature reviews on the nursing workforce in hospitals. The most frequent workplace environmental factors were identified, extracted and clustered in alignment with key constructs for psychological resilience. Six major organizational concepts emerged that related to a positive resilience-building workplace and formed the foundation of the theoretical model. Three concepts related to nursing staff support (professional, practice, personal) and three related to nursing staff development (professional, practice, personal) within the workplace environment. The unified theoretical model incorporates these concepts within the workplace context, linking to the nurse, and then impacting on personal resilience and workplace outcomes, and its use has the potential to increase staff retention and quality of patient care. PMID:27242567

Cost-benefit study of consumer product take-back programs using IBM's WIT reverse logistics optimization tool

NASA Astrophysics Data System (ADS)

Veerakamolmal, Pitipong; Lee, Yung-Joon; Fasano, J. P.; Hale, Rhea; Jacques, Mary

2002-02-01

In recent years, there has been increased focus by regulators, manufacturers, and consumers on the issue of product end of life management for electronics. This paper presents an overview of a conceptual study designed to examine the costs and benefits of several different Product Take Back (PTB) scenarios for used electronics equipment. The study utilized a reverse logistics supply chain model to examine the effects of several different factors in PTB programs. The model was done using the IBM supply chain optimization tool known as WIT (Watson Implosion Technology). Using the WIT tool, we were able to determine a theoretical optimal cost scenario for PTB programs. The study was designed to assist IBM internally in determining theoretical optimal Product Take Back program models and determining potential incentives for increasing participation rates.

Does gratitude enhance prosociality?: A meta-analytic review.

PubMed

Ma, Lawrence K; Tunney, Richard J; Ferguson, Eamonn

2017-06-01

Theoretical models suggest that gratitude is linked to increased prosociality. To date, however, there is a lack of a comprehensive quantitative synthesis of results to support this claim. In this review we aimed to (a) examine the overall strength of the association between gratitude and prosociality, and (b) identify the theoretical and methodological variables that moderate this link. We identified 252 effect sizes from 91 studies across 65 papers-(Total N = 18,342 participants). The present meta-analysis revealed a statistically significant, and moderate positive correlation between gratitude and prosociality (r = .374). This association was significantly larger among studies that assessed reciprocal outcomes relative to nonreciprocal outcomes, and in particular among studies that examined direct -compared with indirect -reciprocity. Studies that examined gratitude as an affective state reported significantly larger effect size studies assessing gratitude as a trait . Studies that examined benefit-triggered gratitude (in response to other's kindness) had a stronger effect that generalized gratitude that focuses on the appreciation of what is valued and cherished in life. Finally, studies that manipulated gratitude in vivo (e.g., economic games) had larger effect sizes compared with those based on recalled incidents when the person felt grateful. We describe the theoretical and practical significance of the results. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Entropic and Electrostatic Effects on the Folding Free Energy of a Surface-Attached Biomolecule: An Experimental and Theoretical Study

PubMed Central

Watkins, Herschel M.; Vallée-Bélisle, Alexis; Ricci, Francesco; Makarov, Dmitrii E.; Plaxco, Kevin W.

2012-01-01

Surface-tethered biomolecules play key roles in many biological processes and biotechnologies. However, while the physical consequences of such surface attachment have seen significant theoretical study, to date this issue has seen relatively little experimental investigation. In response we present here a quantitative experimental and theoretical study of the extent to which attachment to a charged –but otherwise apparently inert– surface alters the folding free energy of a simple biomolecule. Specifically, we have measured the folding free energy of a DNA stem loop both in solution and when site-specifically attached to a negatively charged, hydroxyl-alkane-coated gold surface. We find that, whereas surface attachment is destabilizing at low ionic strength it becomes stabilizing at ionic strengths above ~130 mM. This behavior presumably reflects two competing mechanisms: excluded volume effects, which stabilize the folded conformation by reducing the entropy of the unfolded state, and electrostatics, which, at lower ionic strengths, destabilizes the more compact folded state via repulsion from the negatively charged surface. To test this hypothesis we have employed existing theories of the electrostatics of surface-bound polyelectrolytes and the entropy of surface-bound polymers to model both effects. Despite lacking any fitted parameters, these theoretical models quantitatively fit our experimental results, suggesting that, for this system, current knowledge of both surface electrostatics and excluded volume effects is reasonably complete and accurate. PMID:22239220

Theoretical models of helicopter rotor noise

NASA Technical Reports Server (NTRS)

Hawkings, D. L.

1978-01-01

For low speed rotors, it is shown that unsteady load models are only partially successful in predicting experimental levels. A theoretical model is presented which leads to the concept of unsteady thickness noise. This gives better agreement with test results. For high speed rotors, it is argued that present models are incomplete and that other mechanisms are at work. Some possibilities are briefly discussed.

New method of contour image processing based on the formalism of spiral light beams

NASA Astrophysics Data System (ADS)

Volostnikov, Vladimir G.; Kishkin, S. A.; Kotova, S. P.

2013-07-01

The possibility of applying the mathematical formalism of spiral light beams to the problems of contour image recognition is theoretically studied. The advantages and disadvantages of the proposed approach are evaluated; the results of numerical modelling are presented.

Ongoing data reduction, theoretical studies

NASA Technical Reports Server (NTRS)

Scarf, F. L.; Greenstadt, F. W.

1978-01-01

A nonspecific review of theory, correlative date analysis and supporting research and technology is presented. Title pages in some of the following areas are included: (1) magnetosphere boundary observations; (2) venus ionosphere and solar wind interaction; (3) ISEE-C plasma wave investigation, and (4) solar system plasmas.

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

Ramírez-Morales, A.; Martínez-Orozco, J. C.; Rodríguez-Vargas, I.

The main characteristics of the quantum confined Stark effect (QCSE) are studied theoretically in quantum wells of Gaussian profile. The semi-empirical tight-binding model and the Green function formalism are applied in the numerical calculations. A comparison of the QCSE in quantum wells with different kinds of confining potential is presented.

Normative and Descriptive Aspects of Management Education: Differentiation and Integration

ERIC Educational Resources Information Center

Meirovich, Gavriel

2015-01-01

This study advocates strongly for clear differentiation and synthesis of descriptive and normative approaches in management education. There is a certain isolation of normative and descriptive theoretical frameworks presented in management courses. Normative frameworks in management explain how organizations "should be" managed, while…

Theoretical studies of the RS cannum venaticorum stars

NASA Technical Reports Server (NTRS)

Mullan, D. J.

1981-01-01

Four areas of research were investigated: chromospheric modelling; starspot modelling; supersonic transition locus (STL) crossing; and STL crossing and T Tauri phenomena. Relationships among these areas of research are presented. Stellar structure and mass ejection for these stars were examined along with chromospheric analysis.

The Speaker Respoken: Material Rhetoric as Feminist Methodology.

ERIC Educational Resources Information Center

Collins, Vicki Tolar

1999-01-01

Presents a methodology based on the concept of "material rhetoric" that can help scholars avoid problems as they reclaim women's historical texts. Defines material rhetoric and positions it theoretically in relation to other methodologies, including bibliographical studies, reception theory, and established feminist methodologies. Illustrates…

Defining Mathematical Giftedness

ERIC Educational Resources Information Center

Parish, Linda

2014-01-01

This theoretical paper outlines the process of defining "mathematical giftedness" for a present study on how primary school teaching shapes the mindsets of children who are mathematically gifted. Mathematical giftedness is not a badge of honour or some special value attributed to a child who has achieved something exceptional.…

LONG-TERM IMPACTS OF ORTHOPHOSPHATE TREATMENT ON COPPER LEVELS - PRESENTATION

EPA Science Inventory

Laboratory, pilot, and field data collected support the theoretical "cupric hydroxide" copper solubility model. For the short time frames inherent in laboratory and pilot studies of copper solubility and in initial field monitoring for the LCR from Tier 1 soldered copper sites, c...

Having to Fight

ERIC Educational Resources Information Center

Crowther, Simon; Goodson, Christina; McGuire, James; Dickson, Joanne M.

2013-01-01

Existing research that attempts to understand aggressive behavior often focuses on adults and/or individual traits. The present study used a Grounded Theory approach to develop a theoretical framework of how younger adolescents constructed an understanding of their own aggressive behavior within the social context of their lives. The participants…

Future Directions in Distance Learning and Communication Technologies

ERIC Educational Resources Information Center

Shih, Timothy; Hung, Jason

2007-01-01

Future Directions in Distance Learning and Communication Technologies presents theoretical studies and practical solutions for engineers, educational professionals, and graduate students in the research areas of e-learning, distance education, and instructional design. This book provides readers with cutting-edge solutions and research directions…

Academic Motivation: Concepts, Strategies, and Counseling Approaches

ERIC Educational Resources Information Center

Rowell, Lonnie; Hong, Eunsook

2013-01-01

Motivation is an important foundation of academic development in students. This article discusses academic motivation; its various component concepts in areas such as beliefs, goals, and values; and intrinsic and extrinsic motivation. It also presents major, widely studied theoretical perspectives of academic motivation and briefly illustrates…

Cognitive-Developmental and Behavior-Analytic Theories: Evolving into Complementarity

ERIC Educational Resources Information Center

Overton, Willis F.; Ennis, Michelle D.

2006-01-01

Historically, cognitive-developmental and behavior-analytic approaches to the study of human behavior change and development have been presented as incompatible alternative theoretical and methodological perspectives. This presumed incompatibility has been understood as arising from divergent sets of metatheoretical assumptions that take the form…

Multimodal Narrative Inquiry: Six Teacher Candidates Respond

ERIC Educational Resources Information Center

Morawski, Cynthia M.; Rottmann, Jennifer

2016-01-01

In this paper we present findings of a study on the implementation of a multimodal teacher narrative inquiry component, theoretically grounded by Rosenblatt's theory of transaction analysis, methodologically supported by action research and practically enacted by narrative inquiry and multimodal learning. In particular, the component offered…

Hybrid rocket engine, theoretical model and experiment

NASA Astrophysics Data System (ADS)

Chelaru, Teodor-Viorel; Mingireanu, Florin

2011-06-01

The purpose of this paper is to build a theoretical model for the hybrid rocket engine/motor and to validate it using experimental results. The work approaches the main problems of the hybrid motor: the scalability, the stability/controllability of the operating parameters and the increasing of the solid fuel regression rate. At first, we focus on theoretical models for hybrid rocket motor and compare the results with already available experimental data from various research groups. A primary computation model is presented together with results from a numerical algorithm based on a computational model. We present theoretical predictions for several commercial hybrid rocket motors, having different scales and compare them with experimental measurements of those hybrid rocket motors. Next the paper focuses on tribrid rocket motor concept, which by supplementary liquid fuel injection can improve the thrust controllability. A complementary computation model is also presented to estimate regression rate increase of solid fuel doped with oxidizer. Finally, the stability of the hybrid rocket motor is investigated using Liapunov theory. Stability coefficients obtained are dependent on burning parameters while the stability and command matrixes are identified. The paper presents thoroughly the input data of the model, which ensures the reproducibility of the numerical results by independent researchers.

MEMORY SYSTEMS STUDY. Annual Report No. 2, November 16, 1962 to November 15, 1963

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

Peterson, G R; DeVries, R C; Melsa, J L

1964-10-31

S>Results of theoretical studies of learning control systems are presented. The need for definitions is discussed and definitions of successful, adaptive, and learning control systems are presented. The basic structural elements of learning control systems are discussed. The environmental characteristics of control situations in which learning may be applicable are discussed. Learning control systems are classified in accordance with the environmental situation in which they might operate. The structure and components suitable to various environmental situations are discussed. (auth)

Experimental Study of Dust Grain Charging

NASA Technical Reports Server (NTRS)

Spann, James F; Venturini, Catherine C.; Comfort, Richard H.; Mian, Abbas M.

1999-01-01

The results of an experimental study of the charging mechanisms of micron size dust grains are presented. Individual dust grains are electrodynamically suspended and exposed to an electron beam of known energy and flux, and to far ultraviolet radiation of known wavelength and intensity. Changes in the charge-to-mass ratio of the grain are directly measured as a function of incident beam (electron and/or photon), grain size and composition. Comparisons of our results to theoretical models that predict the grain response are presented.

The Adaptation of the Immigrant Second Generation in America: Theoretical Overview and Recent Evidence

PubMed Central

Portes, Alejandro; Fernández-Kelly, Patricia; Haller, William

2013-01-01

This paper summarises a research program on the new immigrant second generation initiated in the early 1990s and completed in 2006. The four field waves of the Children of Immigrants Longitudinal Study (CILS) are described and the main theoretical models emerging from it are presented and graphically summarised. After considering critical views of this theory, we present the most recent results from this longitudinal research program in the forum of quantitative models predicting downward assimilation in early adulthood and qualitative interviews identifying ways to escape it by disadvantaged children of immigrants. Quantitative results strongly support the predicted effects of exogenous variables identified by segmented assimilation theory and identify the intervening factors during adolescence that mediate their influence on adult outcomes. Qualitative evidence gathered during the last stage of the study points to three factors that can lead to exceptional educational achievement among disadvantaged youths. All three indicate the positive influence of selective acculturation. Implications of these findings for theory and policy are discussed. PMID:23626483

Recent theoretical developments and experimental studies pertinent to vortex flow aerodynamics - With a view towards design

NASA Technical Reports Server (NTRS)

Lamar, J. E.; Luckring, J. M.

1978-01-01

A review is presented of recent progress in a research program directed towards the development of an improved vortex-flow technology base. It is pointed out that separation induced vortex-flows from the leading and side edges play an important role in the high angle-of-attack aerodynamic characteristics of a wide range of modern aircraft. In the analysis and design of high-speed aircraft, a detailed knowledge of this type of separation is required, particularly with regard to critical wind loads and the stability and performance at various off-design conditions. A description of analytical methods is presented. The theoretical methods employed are divided into two classes which are dependent upon the underlying aerodynamic assumptions. One conical flow method is considered along with three different nonconical flow methods. Comparisons are conducted between the described methods and available aerodynamic data. Attention is also given to a vortex flow drag study and a vortex flow wing design using suction analogy.

Temporal flow instability for Magnus-Robins effect at high rotation rates

NASA Astrophysics Data System (ADS)

Sengupta, T. K.; Kasliwal, A.; de, S.; Nair, M.

2003-06-01

The lift and drag coefficients of a circular cylinder, translating and spinning at a supercritical rate is studied theoretically to explain the experimentally observed violation of maximum mean lift coefficient principle, that was proposed heuristically by Prandtl on the basis of inviscid flow model. It is also noted experimentally that flow past a rotating and translating cylinder experiences temporal instability-a fact not corroborated by any theoretical studies so far. In the present paper we report very accurate solution of Navier-Stokes equation that displays the above-mentioned instability and the violation of the maximum limit. The calculated lift coefficient exceeds the limit of /4π, instantaneously as well as in time-averaged sense. The main purpose of the present paper is to explain the observed temporal instability sequence in terms of a new theory of instability based on full Navier-Stokes equation that does not require making any assumption about the flow field, unlike other stability theories.

Quantifying Reinforcement Value and Demand for Psychoactive Substances in Humans

PubMed Central

Heinz, Adrienne J.; Lilje, Todd C.; Kassel, Jon D.; de Wit, Harriet

2013-01-01

Behavioral economics is an emerging cross-disciplinary field that is providing an exciting new contextual framework for researchers to study addictive processes. New initiatives to study addiction under a behavioral economic rubric have yielded variable terminology and differing methods and theoretical approaches that are consistent with the multidimensional nature of addiction. The present article is intended to provide an integrative overview of the behavioral economic nomenclature and to describe relevant theoretical models, principles and concepts. Additionally, we present measures derived from behavioral economic theories that quantify demand for substances and assess decision making processes surrounding substance use. The sensitivity of these measures to different contextual elements (e.g., drug use status, acute drug effects, deprivation) is also addressed. The review concludes with discussion of the validity of these approaches and their potential for clinical application and highlights areas that warrant further research. Overall, behavioral economics offers a compelling framework to help explicate complex addictive processes and it is likely to provide a translational platform for clinical intervention. PMID:23062106

Founder of systems chemistry and foundational theoretical biologist: Tibor Gánti (1933-2009).

PubMed

Szathmáry, Eörs

2015-09-21

With his chemoton theory theoretical biologist and chemical engineer Tibor Gánti was one of the most outstanding intellects behind systems chemistry and the at the foundations of theoretical biology. A brief review of his oeuvre is presented. This essay introduces a special issue dedicated to his memory. Copyright © 2015. Published by Elsevier Ltd.

Advances in Learning and Behavioral Disabilities. Volume 10. Part A: Theoretical Perspectives [and] Part B: Intervention Research.

ERIC Educational Resources Information Center

Scruggs, Thomas E., Ed.; Mastropieri, Margo A., Ed.

This two-volume set presents 11 papers on the state of the art in learning and behavioral disabilities, the first volume, Part A, includes 6 papers providing theoretical perspectives and, the second volume, Part B, includes 5 papers on intervention research. The theoretical papers are: "Defining Emotional or Behavioral Disorders: Divergence…

Strong correlation effects in theoretical STM studies of magnetic adatoms

NASA Astrophysics Data System (ADS)

Dang, Hung T.; dos Santos Dias, Manuel; Liebsch, Ansgar; Lounis, Samir

2016-03-01

We present a theoretical study for the scanning tunneling microscopy (STM) spectra of surface-supported magnetic nanostructures, incorporating strong correlation effects. As concrete examples, we study Co and Mn adatoms on the Cu(111) surface, which are expected to represent the opposite limits of Kondo physics and local moment behavior, using a combination of density functional theory and both quantum Monte Carlo and exact diagonalization impurity solvers. We examine in detail the effects of temperature T , correlation strength U , and impurity d electron occupancy Nd on the local density of states. We also study the effective coherence energy scale, i.e., the Kondo temperature TK, which can be extracted from the STM spectra. Theoretical STM spectra are computed as a function of STM tip position relative to each adatom. Because of the multiorbital nature of the adatoms, the STM spectra are shown to consist of a complicated superposition of orbital contributions, with different orbital symmetries, self-energies, and Kondo temperatures. For a Mn adatom, which is close to half-filling, the STM spectra are featureless near the Fermi level. On the other hand, the quasiparticle peak for a Co adatom gives rise to strongly position-dependent Fano line shapes.

Study on Predicting Axial Load Capacity of CFST Columns

NASA Astrophysics Data System (ADS)

Ravi Kumar, H.; Muthu, K. U.; Kumar, N. S.

2017-11-01

This work presents an analytical study and experimental study on the behaviour and ultimate load carrying capacity of axially compressed self-compacting concrete-filled steel tubular columns. Results of tests conducted by various researchers on 213 samples concrete-filled steel tubular columns are reported and present authors experimental data are reported. Two theoretical equations were derived for the prediction of the ultimate axial load strength of concrete-filled steel tubular columns. The results from prediction were compared with the experimental data. Validation to the experimental results was made.

An introduction to genetic quality in the context of sexual selection.

PubMed

Pitcher, Trevor E; Mays, Herman L

2008-09-01

This special issue of Genetica brings together empirical researchers and theoreticians to present the latest on the evolutionary ecology of genetic quality in the context of sexual selection. The work comes from different fields of study including behavioral ecology, quantitative genetics and molecular genetics on a diversity of organisms using different approaches from comparative studies, mathematical modeling, field studies and laboratory experiments. The papers presented in this special issue primarily focus on genetic quality in relation to (1) sources of genetic variation, (2) polyandry, (3) new theoretical developments and (4) comprehensive reviews.

Comparison of predicted and measured low-speed performance of two 51 centimeter-diameter inlets at incidence angle

NASA Technical Reports Server (NTRS)

Albers, J. A.

1973-01-01

Theoretical and experimental internal flow characteristics of two 51-cm-diameter inlets are compared. Theoretical flow characteristics along the inlet surface were obtained from an axisymmetric potential flow and boundary layer analysis. The experimental data were obtained from low-speed tests of a high-bypass-ratio turbofan engine simulator. Comparisons between calculated internal surface pressure distributions and experimental data are presented for a free-system velocity of 45 m/sec and for incidence angles from 0 deg to 50 deg. Analysis of boundary layer separation on the inlet lip at incidence angle is the major emphasis of this report. Theoretical boundary layer shape factors, skin friction coefficients, and velocity profiles in the boundary layer are presented, along with the location of the transition region. Theoretical and experimental separation locations are also discussed.

Impulsive control of stochastic systems with applications in chaos control, chaos synchronization, and neural networks.

PubMed

Li, Chunguang; Chen, Luonan; Aihara, Kazuyuki

2008-06-01

Real systems are often subject to both noise perturbations and impulsive effects. In this paper, we study the stability and stabilization of systems with both noise perturbations and impulsive effects. In other words, we generalize the impulsive control theory from the deterministic case to the stochastic case. The method is based on extending the comparison method to the stochastic case. The method presented in this paper is general and easy to apply. Theoretical results on both stability in the pth mean and stability with disturbance attenuation are derived. To show the effectiveness of the basic theory, we apply it to the impulsive control and synchronization of chaotic systems with noise perturbations, and to the stability of impulsive stochastic neural networks. Several numerical examples are also presented to verify the theoretical results.

Minimum film thickness in elliptical contacts for different regimes of fluid-film lubrication

NASA Technical Reports Server (NTRS)

Hamrock, B. J.; Dowson, D.

1978-01-01

The film-parameter equations are provided for four fluid-film lubrication regimes found in elliptical contacts. These regimes are isoviscous-rigid; viscous-rigid; elastohydrodynamic of low-elastic-modulus materials, or isoviscous-elastic; and elastohydrodynamic, or viscous-elastic. The influence or lack of influence of elastic and viscous effects is the factor that distinguishes these regimes. The film-parameter equations for the respective regimes come from earlier theoretical studies by the authors on elastohydrodynamic and hydrodynamic lubrication of elliptical conjunctions. These equations are restated and the results are presented as a map of the lubrication regimes, with film-thickness contours on a log-log grid of the viscosity and elasticity parameters for five values of the ellipticity parameter. The results present a complete theoretical film-parameter solution for elliptical contacts in the four lubrication regimes.

Additive erosion reduction influences in the turbulent boundary layer

NASA Astrophysics Data System (ADS)

Buckingham, A. C.

1981-05-01

Results of a sequence of flow, heat and mass transfer calculations are presented which theoretically characterize the erosive environment at the wall surface of refractory metal coated and uncoated gun barrels. The theoretical results include analysis of the wall surface temperature, heat flux, and shear stress time histories on thin (10 mil.) Cr, Mo, Nb, and Ta plated steel barrel walls as uncoated steel walls. The calculations combine effects of a number of separate processes which were previously (and purposely) studied individually. These include solid particle additive concentrations, gas wall thermochemical influences, and transient turbulent wall boundary layer flow with multicomponent molecular diffusion and reactions from interaction of propellant combustion and the eroding surface. The boundary layer model includes particulate additive concentrations as well as propellant combustion products, considered for the present to be in the local thermochemical equilibrium.

Unmagnetized diffusion for azimuthally symmetric wave and particle distributions

NASA Technical Reports Server (NTRS)

Dusenbery, P. B.; Lyons, L. R.

1988-01-01

The quasi-linear diffusion of particles from resonant interactions with a spectrum of electrostatic waves is investigated theoretically, extending results obtained for no magnetic field and for strong magnetic fields to cases where the ambient magnetic field which organizes azimuthally symmetric wave and particle distributions does not have to be taken into consideration in evaluating the local interaction. The derivation of the governing equations is explained, and numerical results are presented in extensive graphs and characterized in detail. Slow-mode ion-acoustic waves are shown to be unstable under the plasma conditions studied, and the dependence of resonant-ion diffusion rates with pitch angle, speed, and the distribution of wave energy in wavenumber space is explored. The implications of the present findings for theoretical models of the earth bow shock and plasma-sheet boundary layer are indicated.

More similarities than differences in contemporary theories of social development?: a plea for theory bridging.

PubMed

Leaper, Campbell

2011-01-01

Many contemporary theories of social development are similar and/or share complementary constructs. Yet, there have been relatively few efforts toward theoretical integration. The present chapter represents a call for increased theory bridging. The problem of theoretical fragmentation in psychology is reviewed. Seven highlighted reasons for this predicament include differences between behavioral sciences and other sciences, theoretical paradigms as social identities, the uniqueness assumption, information overload, field fixation, linguistic fragmentation, and few incentives for theoretical integration. Afterward, the feasibility of theoretical synthesis is considered. Finally, some possible directions are proposed for theoretical integration among five contemporary theories of social and gender development: social cognitive theory, expectancy-value theory, cognitive-developmental theory, gender schema theory, and self-categorization theory.

Disarming the Threat to Feminist Identification: An Application of Personal Construct Theory to Measurement and Intervention

ERIC Educational Resources Information Center

Moradi, Bonnie; Martin, Annelise; Brewster, Melanie E.

2012-01-01

Many individuals endorse feminist values but do not identify as feminist. The present set of studies tests the concept of threat, grounded in G. A. Kelly's personal construct theory of personality, as a potential factor in feminist nonidentification. Study 1 introduces the theoretically grounded "Feminist Threat Index" and evaluates its…

A theoretical study of optical contact of vitreous silica

NASA Technical Reports Server (NTRS)

Barber, T. D.

1972-01-01

Optical contact has been proposed as a method of bonding quartz parts of the Stanford relativity satellite. The theory of the van der Waals force is outlined and applied to the problem of optical contact. The effect of various contaminations is discussed and a program of experimentation for further study of the problem is presented.

Does Observed Controlling Teaching Behavior Relate to Students' Motivation in Physical Education?

ERIC Educational Resources Information Center

De Meyer, Jotie; Tallir, Isabel B.; Soenens, Bart; Vansteenkiste, Maarten; Aelterman, Nathalie; Van den Berghe, Lynn; Speleers, Lise; Haerens, Leen

2014-01-01

Self-determination theory (SDT) has served as a theoretical framework for considerable research on teaching behavior and student motivation. The majority of studies have focused on need-supportive teaching behavior at the expense of need-thwarting teaching behavior (i.e., the "dark side" of teaching). The goal of the present study was to…

Focusing on Interactions between Content and Cognition: A New Perspective on Gender Differences in Mathematical Sub-Competencies

ERIC Educational Resources Information Center

George, Ann Cathrice; Robitzsch, Alexander

2018-01-01

This article presents a new perspective on measuring gender differences in the large-scale assessment study Trends in International Science Study (TIMSS). The suggested empirical model is directly based on the theoretical competence model of the domain mathematics and thus includes the interaction between content and cognitive sub-competencies.…

Examining Massification Policies and Their Consequences for Equality in Chinese Higher Education: A Cultural Perspective

ERIC Educational Resources Information Center

Liu, Jian

2012-01-01

This study extends the theoretical perspectives in policy studies on the issue of educational equality by analyzing the influence of cultural values on policies and policy processes. The present paper first teases out the key cultural values regarding education and equality, and then explores how these values shape the institution and policy…