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Sample records for activity theoretical perspective

  1. Responsibility in Dental Praxis: An Activity Theoretical Perspective

    ERIC Educational Resources Information Center

    Ardenghi, Diego Machado; Roth, Wolff-Michael; Pozzer-Ardenghi, Lilian

    2007-01-01

    Purpose--The purpose of this paper is to investigate the transitions practitioners undergo as they move from dental school to their first job in a dental clinic and their learning in the workplace. The paper aims to investigate their use of ethical principles as they engage in practice, providing a theoretical explanation for the gap practitioners…

  2. Cryptobiosis: a new theoretical perspective.

    PubMed

    Neuman, Yair

    2006-10-01

    The tardigrade is a microscopic creature that under environmental stress conditions undergoes cryptobiosis [Feofilova, E.P., 2003. Deceleration of vital activity as a universal biochemical mechanism ensuring adaptation of microorganisms to stress factors: A review. Appl. Biochem. Microbiol. 39, 1-18; Nelson, D.R., 2002. Current status of the tardigrada: Evolution and ecology. Integrative Comp. Biol. 42, 652-659]-a temporary metabolic depression-which is considered to be a third state between life and death [Clegg, J.S., 2001. Cryptobiosis-a peculiar state of biological organization. Comp. Biochem. Physiol. Part B 128, 613-624]. In contrast with death, cryptobiosis is a reversible state, and as soon as environmental conditions change, the tardigrade "returns to life." Cryptobiosis in general, and among the tardigrade in particular, is a phenomenon poorly understood [Guppy, M., 2004. The biochemistry of metabolic depression: a history of perceptions. Comp. Biochem. Physiol. Part B 139, 435-442; Schill, R.O., et al., 2004. Stress gene (hsp70) sequences and quantitative expression in Milensium tardigradum (Tardigrade) during active and cryptobiotic stages. J. Exp. Biol. 207, 1607-1613; Watanabe, M., et al., 2002. Mechanisn allowing an insect to survive complete dehydration and extreme temperatures. J. Exp. Biol. 205, 2799-2802; Wright, J.C., 2001. Cryptobiosis 300 years on from van Leuwenhoek: what have we learned about tardigrades? Zool. Anz. 240, 563-582]. Moreover, the ability of the tardigrade to bootstrap itself and to return to life seems paradoxical like the legendary Baron von Munchausen who pulled himself out of the swamp by grabbing his own hair. Two theoretical obstacles prevent us from advancing our knowledge of cryptobiosis. First, we lack appropriate theoretical understanding of reversible processes of biological computation in living systems. Second, we lack appropriate theoretical understanding of bootstrapping in living systems. In this short opinion

  3. Dark matter: Theoretical perspectives

    SciTech Connect

    Turner, M.S. Fermi National Accelerator Lab., Batavia, IL )

    1993-06-01

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

  4. Dark matter: theoretical perspectives.

    PubMed Central

    Turner, M S

    1993-01-01

    I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that (i) there are no dark-matter candidates within the "standard model" of particle physics, (ii) there are several compelling candidates within attractive extensions of the standard model of particle physics, and (iii) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for "new physics." The compelling candidates are a very light axion (10(-6)-10(-4) eV), a light neutrino (20-90 eV), and a heavy neutralino (10 GeV-2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos. PMID:11607395

  5. Dark matter: Theoretical perspectives

    SciTech Connect

    Turner, M.S. |

    1993-01-01

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

  6. Dark matter: Theoretical perspectives

    SciTech Connect

    Turner, M.S. . Enrico Fermi Inst. Fermi National Accelerator Lab., Batavia, IL )

    1993-01-01

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

  7. Theoretical Perspectives for Developmental Education.

    ERIC Educational Resources Information Center

    Lundell, Dana Britt, Ed.; Higbee, Jeanne L., Ed.

    This monograph from the University of Minnesota General College (GC) discusses theoretical perspectives on developmental education from both new and established standpoints. GC voluntarily eliminated its degree programs in order to focus on preparing under-prepared students for transfer to the university system. GC's curricular model includes a…

  8. Theoretical perspectives on narrative inquiry.

    PubMed

    Emden, C

    1998-04-01

    Narrative inquiry is gaining momentum in the field of nursing. As a research approach it does not have any single heritage of methodology and its practitioners draw upon diverse sources of influence. Central to all narrative inquiry however, is attention to the potential of stories to give meaning to people's lives, and the treatment of data as stories. This is the first of two papers on the topic and addresses the theoretical influences upon a particular narrative inquiry into nursing scholars and scholarship. The second paper, Conducting a narrative analysis, describes the actual narrative analysis as it was conducted in this same study. Together, the papers provide sufficient detail for others wishing to pursue a similar approach to do so, or to develop the ideas and procedures according to their own way of thinking. Within this first theoretical paper, perspectives from Jerome Bruner (1987) and Wade Roof (1993) are outlined. These relate especially to the notion of stories as 'imaginative constructions' and as 'cultural narratives' and as such, highlight the profound importance of stories as being individually and culturally meaningful. As well, perspectives on narrative inquiry from nursing literature are highlighted. Narrative inquiry in this instance lies within the broader context of phenomenology.

  9. Peer support: a theoretical perspective.

    PubMed

    Mead, S; Hilton, D; Curtis, L

    2001-01-01

    This article offers one theoretical perspective of peer support and attempts to define the elements that, when reinforced through education and training, provide a new cultural context for healing and recovery. Persons labeled with psychiatric disability have become victims of social and cultural ostracism and consequently have developed a sense of self that reinforces the "patient" identity. Enabling members of peer support to understand the nature and impact of these cultural forces leads individuals and peer communities toward a capacity for personal, relational, and social change. It is our hope that consumers from all different types of programs (e.g. drop-in, social clubs, advocacy, support, outreach, respite), traditional providers, and policy makers will find this article helpful in stimulating dialogue about the role of peer programs in the development of a recovery based system.

  10. An Activity Theoretical Perspective towards the Design of an ICT-Enhanced After-School Programme for Academically At-Risk Students

    ERIC Educational Resources Information Center

    Tay, Lee Yong; Lim, Cher Ping

    2010-01-01

    This paper examines how a game-like 3D Multi-User Virtual Environment (MUVE), Quest Atlantis (QA), is used in an after-school programme to engage a group of 14 academically at-risk primary students in their learning. It adopts an activity theoretical perspective to identify the disturbances and contradictions during the implementation of the…

  11. Organized Out-of-School Activities and Peer Relationships: Theoretical Perspectives and Previous Research

    ERIC Educational Resources Information Center

    Fredricks, Jennifer A.; Simpkins, Sandra D.

    2013-01-01

    The goal of this volume is to show how organized activities provide an ideal setting for developing a deeper understanding of peer relations, as well as offering a context for a more positive study of peers. The chapters in this volume focus on youth 10 to 18 years of age. In this introductory chapter we first describe the reasons why organized…

  12. Modes of Engagement in Foreign Language Writing: An Activity Theoretical Perspective

    ERIC Educational Resources Information Center

    Haneda, Mari

    2007-01-01

    This article makes the case for using activity theory to explore the learning and teaching of writing in a foreign language. I illustrate my argument by bringing this theory to bear on a re-examination of the different modes of engagement in writing by university-level students of Japanese as a foreign language that I identified in an earlier…

  13. Students' Representations of Scientific Practice during a Science Internship: Reflections from an Activity-Theoretic Perspective

    ERIC Educational Resources Information Center

    Hsu, Pei-Ling; van Eijck, Michiel; Roth, Wolff-Michael

    2010-01-01

    Working at scientists' elbows is one suggestion that educators make to improve science education, because such "authentic experiences" provide students with various types of science knowledge. However, there is an ongoing debate in the literature about the assumption that authentic science activities can enhance students' understandings…

  14. Students' Representations of Scientific Practice during a Science Internship: Reflections from an activity-theoretic perspective

    NASA Astrophysics Data System (ADS)

    Hsu, Pei-Ling; van Eijck, Michiel; Roth, Wolff-Michael

    2010-06-01

    Working at scientists' elbows is one suggestion that educators make to improve science education, because such "authentic experiences" provide students with various types of science knowledge. However, there is an ongoing debate in the literature about the assumption that authentic science activities can enhance students' understandings of scientific practice. The purpose of the study is to further address the debate in terms of the ethnographic data collected during an internship programme for high school students right through to their public presentations at the end. Drawing on activity theory to analyse these presentations, we found that students presented scientific practice as accomplished by individual personnel without collaboration in the laboratory. However, our ethnographic data of their internship interaction show that students have had conversations about the complex collaborations within and outside the laboratory. This phenomenon leads us to claim that students experienced authentic science in their internships, but their subsequent representations of authentic science are incomplete. That is, participating in authentic science internships and reporting scientific practice are embedded activities that constitute different goals and conditions rather than unrefracted reflections of one another. The debate on the influence on students' understanding of science practice is not simply related to situating students in authentic science contexts, but also related to students' values and ideology of reporting their understanding of and about science. To help students see these "invisible" moments of science practice is therefore crucial. We make suggestions for how the invisible in and of authentic science may be made visible.

  15. Preservice elementary teachers' development of pedagogical design capacity for inquiry---an activity-theoretical perspective

    NASA Astrophysics Data System (ADS)

    Forbes, Cory T.

    Preservice elementary teachers need to begin developing their pedagogical design capacities for inquiry by learning how to translate their conceptions of inquiry into classroom practice through the adaptation and enactment of curriculum materials. Using both qualitative and quantitative research methods, I draw upon cultural-historical activity theory (CHAT) to investigate preservice elementary teachers' curriculum design and development of pedagogical design capacity for inquiry during the final year of their teacher education program. This study involved analysis of curricular artifacts and survey data from 46 prospective elementary teachers in two sections of an undergraduate elementary science teaching methods course, as well as interviews, observational fieldnotes, reflective journals, and other artifacts from four preservice teachers from this larger group studied during the methods and student teaching semesters. Results show that preservice teachers were able to translate their espoused inquiry frameworks into planned and enacted science lessons. This involved adapting existing curriculum materials to better promote specific inquiry practices, but also to fundamentally shift the nature of classroom science. The preservice teachers' curriculum design efforts were constrained, however, by features of their institutional contexts and subject to emergent tensions. In attempting to resolve these tensions through curriculum design for inquiry, the preservice teachers ultimately articulated a fundamental contradiction between two distinct and competing visions for classroom inquiry: traditional classroom science, which promotes students' reproduction of scientific explanations by objectifying students, and a novel form of classroom inquiry that repositions students as contributing community members involved in the co-construction of knowledge through lesson-specific shared problem-spaces. For each of the preservice teachers, this contradiction had important

  16. Evolution of Theoretical Perspectives in My Research

    NASA Astrophysics Data System (ADS)

    Otero, Valerie K.

    2009-11-01

    Over the past 10 years I have been using socio-cultural theoretical perspectives to understand how people learn physics in a highly interactive, inquiry-based physics course such as Physics and Everyday Thinking [1]. As a result of using various perspectives (e.g. Distributed Cognition and Vygotsky's Theory of Concept Formation), my understanding of how these perspectives can be useful for investigating students' learning processes has changed. In this paper, I illustrate changes in my thinking about the role of socio-cultural perspectives in understanding physics learning and describe elements of my thinking that have remained fairly stable. Finally, I will discuss pitfalls in the use of certain perspectives and discuss areas that need attention in theoretical development for PER.

  17. Complexity Leadership: A Theoretical Perspective

    ERIC Educational Resources Information Center

    Baltaci, Ali; Balci, Ali

    2017-01-01

    Complex systems are social networks composed of interactive employees interconnected through collaborative, dynamic ties such as shared goals, perspectives and needs. Complex systems are largely based on "the complex system theory". The complex system theory focuses mainly on finding out and developing strategies and behaviours that…

  18. Theoretical perspectives on strange physics

    SciTech Connect

    Ellis, J.

    1983-04-01

    Kaons are heavy enough to have an interesting range of decay modes available to them, and light enough to be produced in sufficient numbers to explore rare modes with satisfying statistics. Kaons and their decays have provided at least two major breakthroughs in our knowledge of fundamental physics. They have revealed to us CP violation, and their lack of flavor-changing neutral interactions warned us to expect charm. In addition, K/sup 0/-anti K/sup 0/ mixing has provided us with one of our most elegant and sensitive laboratories for testing quantum mechanics. There is every reason to expect that future generations of kaon experiments with intense sources would add further to our knowledge of fundamental physics. This talk attempts to set future kaon experiments in a general theoretical context, and indicate how they may bear upon fundamental theoretical issues. A survey of different experiments which would be done with an Intense Medium Energy Source of Strangeness, including rare K decays, probes of the nature of CP isolation, ..mu.. decays, hyperon decays and neutrino physics is given. (WHK)

  19. Theoretical Perspectives of How Digital Natives Learn

    ERIC Educational Resources Information Center

    Kivunja, Charles

    2014-01-01

    Marck Prensky, an authority on teaching and learning especially with the aid of Information and Communication Technologies, has referred to 21st century children born after 1980 as "Digital Natives". This paper reviews literature of leaders in the field to shed some light on theoretical perspectives of how Digital Natives learn and how…

  20. Theoretical Perspectives on Mathematics Teacher Change

    ERIC Educational Resources Information Center

    Goos, Merrilyn; Geiger, Vince

    2010-01-01

    In this review essay we critically examine issues raised by authors whose work is published in the two Special Issues of "JMTE" (Part 1, 13.5 and Part 2, 13.6) on Mathematics Teacher and Mathematics Teacher Educator Change--Insight through Theoretical Perspectives. While the authors have drawn on a wide range of theories and approaches, we have…

  1. 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'…

  2. From Disks To Planets: A Theoretical Perspective

    NASA Astrophysics Data System (ADS)

    Bromley, Ben

    2016-07-01

    Circumstellar disks of gas and dust naturally produce planets. Observations of young stellar systems tell us the starting conditions, while planet surveys reveal an amazing diversity of outcomes. Theory tries to connect the dots with ideas on how planets emerge from dust within an evolving gas disk. Here I give a broad-brush view of planet formation from a theoretical perspective, noting recent ideas and successes. I also consider the challenges. The conversion of primordial dust into planetesimals is uncertain. Even the mass budget in solids is a problem, since the total mass in dust observed around young stars seems insufficient to account for the census of full-fledged planets. Toward resolving these issues, the Atacama Large Millimeter Array and the Karl G. Jansky Very Large Array are playing key roles in illuminating how disks become planets.

  3. Understanding the enhanced catalytic activity of Cu1@Pd3(111) in formic acid dissociation, a theoretical perspective

    NASA Astrophysics Data System (ADS)

    He, Feng; Li, Kai; Xie, Guangyou; Wang, Ying; Jiao, Menggai; Tang, Hao; Wu, Zhijian

    2016-06-01

    The bimetallic Cu1@Pd3(111) catalyst has been synthesized recently and exhibits better catalytic activity and durability compared with pure Pd(111) as anode catalyst in direct formic acid fuel cells (DFAFCs). In this work, we studied the reaction mechanism of formic acid dissociation on both Pd(111) and Cu1@Pd3(111) by using the density functional method. Our calculations showed that the surface adsorption of the poisoning species CO on Cu1@Pd3(111) is weakened mainly by the strain effect rather than the Cusbnd Pd ligand effect. The Cu1@Pd3(111) can effectively promote the catalytic activity for formic acid dissociation by decreasing the barrier of CO2 formation from the preferential trans-COOH intermediate and increasing the barrier of CO formation from the reduction of CO2. We found that the H atom accumulation, electron accumulation and low electrode potential could accelerate the catalyst deactivation due to the contamination of the poisoning species CO. Furthermore, under low anode potential, the Cu1@Pd3(111) has better durability than pure Pd(111), which can be attributed to the unfavorable CO formation and the favorable CO desorption.

  4. Photolytic properties of cobalamins: a theoretical perspective.

    PubMed

    Kozlowski, Pawel M; Garabato, Brady D; Lodowski, Piotr; Jaworska, Maria

    2016-03-21

    This Perspective Article highlights recent theoretical developments, and summarizes the current understanding of the photolytic properties of cobalamins from a computational point of view. The primary focus is on two alkyl cobalamins, methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl), as well as two non-alkyl cobalamins, cyanocobalamin (CNCbl) and hydroxocobalamin (HOCbl). Photolysis of alkyl cobalamins involves low-lying singlet excited states where photodissociation of the Co-C bond leads to formation of singlet-born alkyl/cob(ii)alamin radical pairs (RPs). Potential energy surfaces (PESs) associated with cobalamin low-lying excited states as functions of both axial bonds, provide the most reliable tool for initial analysis of their photochemical and photophysical properties. Due to the complexity, and size limitations associated with the cobalamins, the primary method for calculating ground state properties is density functional theory (DFT), while time-dependent DFT (TD-DFT) is used for electronically excited states. For alkyl cobalamins, energy pathways on the lowest singlet surface, connecting metal-to-ligand charge transfer (MLCT) and ligand field (LF) minima, can be associated with photo-homolysis of the Co-C bond observed experimentally. Additionally, energy pathways between minima and seams associated with crossing of S1/S0 surfaces, are the most efficient for internal conversion (IC) to the ground state. Depending on the specific cobalamin, such IC may involve simultaneous elongation of both axial bonds (CNCbl), or detachment of axial base followed by corrin ring distortion (MeCbl). The possibility of intersystem crossing, and the formation of triplet RPs is also discussed based on Landau-Zener theory.

  5. Information-Theoretic Perspectives on Geophysical Models

    NASA Astrophysics Data System (ADS)

    Nearing, Grey

    2016-04-01

    practice of science (except by Gong et al., 2013, whose fundamental insight is the basis for this talk), and here I offer two examples of practical methods that scientists might use to approximately measure ontological information. I place this practical discussion in the context of several recent and high-profile experiments that have found that simple out-of-sample statistical models typically (vastly) outperform our most sophisticated terrestrial hydrology models. I offer some perspective on several open questions about how to use these findings to improve our models and understanding of these systems. Cartwright, N. (1983) How the Laws of Physics Lie. New York, NY: Cambridge Univ Press. Clark, M. P., Kavetski, D. and Fenicia, F. (2011) 'Pursuing the method of multiple working hypotheses for hydrological modeling', Water Resources Research, 47(9). Cover, T. M. and Thomas, J. A. (1991) Elements of Information Theory. New York, NY: Wiley-Interscience. Cox, R. T. (1946) 'Probability, frequency and reasonable expectation', American Journal of Physics, 14, pp. 1-13. Csiszár, I. (1972) 'A Class of Measures of Informativity of Observation Channels', Periodica Mathematica Hungarica, 2(1), pp. 191-213. Davies, P. C. W. (1990) 'Why is the physical world so comprehensible', Complexity, entropy and the physics of information, pp. 61-70. Gong, W., Gupta, H. V., Yang, D., Sricharan, K. and Hero, A. O. (2013) 'Estimating Epistemic & Aleatory Uncertainties During Hydrologic Modeling: An Information Theoretic Approach', Water Resources Research, 49(4), pp. 2253-2273. Jaynes, E. T. (2003) Probability Theory: The Logic of Science. New York, NY: Cambridge University Press. Nearing, G. S. and Gupta, H. V. (2015) 'The quantity and quality of information in hydrologic models', Water Resources Research, 51(1), pp. 524-538. Popper, K. R. (2002) The Logic of Scientific Discovery. New York: Routledge. Van Horn, K. S. (2003) 'Constructing a logic of plausible inference: a guide to cox's theorem

  6. Why Could Father Involvement Benefit Children? Theoretical Perspectives

    ERIC Educational Resources Information Center

    Pleck, Joseph H.

    2007-01-01

    Four theoretical perspectives about why father involvement could have positive consequences for child development are briefly reviewed: attachment theory, social capital theory, Bronfenbrenner's ecological theory, and "essential father" theory. Strengths and weaknesses of each perspective are discussed, and the prospects for an integrated…

  7. An Emerging Theoretical Perspective for Research in Human Development.

    ERIC Educational Resources Information Center

    Bronfenbrenner, Urie

    The emergence of a new theoretical framework for research in human development is discussed. The theoretical perspective is contrasted with the classical laboratory experiment, which produces ecologically invalid research because of the restrictions of the artificial laboratory environment. The emerging framework enhances ecological validity by…

  8. Migration and Development: A Theoretical Perspective 1

    PubMed Central

    De Haas, Hein

    2010-01-01

    The debate on migration and development has swung back and forth like a pendulum, from developmentalist optimism in the 1950s and 1960s, to neo‐Marxist pessimism over the 1970s and 1980s, towards more optimistic views in the 1990s and 2000s. This paper argues how such discursive shifts in the migration and development debate should be primarily seen as part of more general paradigm shifts in social and development theory. However, the classical opposition between pessimistic and optimistic views is challenged by empirical evidence pointing to the heterogeneity of migration impacts. By integrating and amending insights from the new economics of labor migration, livelihood perspectives in development studies and transnational perspectives in migration studies – which share several though as yet unobserved conceptual parallels – this paper elaborates the contours of a conceptual framework that simultaneously integrates agency and structure perspectives and is therefore able to account for the heterogeneous nature of migration‐development interactions. The resulting perspective reveals the naivety of recent views celebrating migration as self‐help development “from below”. These views are largely ideologically driven and shift the attention away from structural constraints and the vital role of states in shaping favorable conditions for positive development impacts of migration to occur. PMID:26900199

  9. Why Network? Theoretical Perspectives on Networking

    ERIC Educational Resources Information Center

    Muijs, Daniel; West, Mel; Ainscow, Mel

    2010-01-01

    In recent years, networking and collaboration have become increasingly popular in education. However, there is at present a lack of attention to the theoretical basis of networking, which could illuminate when and when not to network and under what conditions networks are likely to be successful. In this paper, we will attempt to sketch the…

  10. Anxiety: towards a decision-theoretic perspective.

    PubMed

    Shechter, M; Zeidner, M

    1990-05-01

    This paper sets out to illustrate how anxiety may be incorporated into a formal decision theoretic utility model of choice, and to suggest several measurement procedures towards that end. The major propositions derived and posited in this paper lend considerable support to intuitive notions with respect to the effects of anxiety on human behaviour in risky decision situations. Namely, that the willingness of an individual to pay to reduce health risks (an economic indicator of individual welfare associated with reduced morbidity or increased longevity) tends to be positive and higher when anxiety is present than when it is not. The formal results of the analysis show that when psychological considerations are incorporated into a state-dependent utility model, the normative results customarily obtained concerning value-of-life need to be qualified.

  11. Magnetic Reconnection: Theoretical and Observational Perspectives: Preface

    NASA Technical Reports Server (NTRS)

    Lewis, W. S.; Antiochos, S. K,; Drake, J. F.

    2011-01-01

    Magnetic reconnection is a fundamental plasma-physical process by which energy stored in a magnetic field is converted, often explosively, into heat and the kinetic energy of the charged particles that constitute the plasma. It occurs in a variety of astrophysical settings, ranging from the solar corona to pulsar magnetospheres and winds, as well as in laboratory fusion experiments, where it is responsible for sawtooth crashes. First proposed by R.G. Giovanelli in the late I 940s as the mechanism responsible for solar flares, magnetic reconnection was invoked at the beginning of the space age to explain not just solar flares but also the transfer of energy, mass, and momentum from the solar wind to Earth's magnetosphere and the subsequent storage and release of the transferred energy in the magnetotai\\. During the half century or so that has followed the seminal theoretical works by J.W. Dungey, P.A. Sweet, E.N. Parker, and H.E. Petschek, in-situ measurements by Earth-orbiting satellites and remote-sensing observations of the solar corona have provided a growing body of evidence for the occurrence of reconnection at the Sun, in the solar wind, and in the near-Earth space environment. The last thirty years have also seen the development of laboratory reconnection experiments at a number of institutions. In parallel with the efforts of experimentalists in both space and laboratory plasma physics, theorists have investigated, analytically and with the help of increasingly powerful MHD, hybrid, and kinetic numerical simulations, the structure of the diffusion region, the factors controlling the rate, onset, and cessation of reconnection, and the detailed physics that enables the demagnetization of the ions and electrons and the topological reconfiguration of the magnetic field. Moreover, the scope of theoretical reconnection studies has been extended well beyond solar system and laboratory plasmas to include more exotic astrophysical plasma systems whose strong (10

  12. Theoretical perspectives of terrorist enemies as networks.

    SciTech Connect

    Spulak, Robert George, Jr.; Glicken, Jessica

    2005-08-01

    This perspective of terrorist enemies as networks by two distinguished associate fellows of the Joint Special Operations University (JSOU) follows as a result of its recent initiative to support USSOCOM strategic planning for the Global War on Terrorism. The paper is a manifestation of JSOU's goals for contributing products that will advance SOF strategic art and generating strategic outreach to the military, civilian, and academic communities to enrich those products. Dr. Robert Spulak and Dr. Jessica Glicken Turnley presented the findings of this paper to assembled strategic planners from USSOCOM, other combatant commands, and interagency players at the Center for Special Operations plan development conference, September 2005, in Tampa, Florida. At that meeting, the authors put forward a number of helpful planning concepts based on their professional studies in science and the humanities and their experiences in government and business. The JSOU Strategic Studies Department is pleased to facilitate the association of USSOCOM strategic planners with civilian expertise and insights that can broaden military thought and encourage planning decisions directly relevant to the changing global environment. Through JSOU's strategic outreach initiative, experts in many professional disciplines have signaled their willingness to support the Nation's counterterrorism efforts. In that spirit, JSOU is proud to commend this paper to SOF readers and appreciates the support of Dr. Spulak and Dr. Turnley.

  13. Theoretical Perspectives on Assessment in Cooperative Education Placements

    ERIC Educational Resources Information Center

    Hodges, David; Eames, Chris; Coll, Richard K.

    2014-01-01

    In this paper we examine theoretical perspectives on assessment in cooperative education placements. As assessment is linked to student learning, we focus briefly on the purposes of assessment. We then consider a range of learning theories that have been, and are more recently, explored as ways to explain the process of learning on cooperative…

  14. Disintegration, recognition, and violence: a theoretical perspective.

    PubMed

    Heitmeyer, Wilhelm; Anhut, Reimund

    2008-01-01

    The literature explaining deviance, criminality, or violence offers a broad spectrum of approaches in criminology and sociology. Mostly the theories focus on specific levels of explanation like the macrolevel (for example, strain theories) or the microlevel (for example, self-control theory).This article presents a relatively new theoretical approach combining different levels and focusing on three dimensions associated with specific kinds of recognition: social-structural, institutional, and socioemotional. The social-structural dimension refers to access to the functional systems of society and the accompanying recognition of position, status, and so on. The institutional dimension concentrates on the opportunity to participate in public affairs with the aim of getting moral recognition. The socioemotional dimension emphasizes the quantity and quality of integration in and social support from families, friends, partners, and so on, which provide emotional recognition.The underlying idea is that lack of access, participation, and belonging causes a lack of recognition. When this happens, social and individual problems increase. Thus, deviant and violent behavior can be seen as one potential reaction to a lack of recognition and as a way to gain status and recognition in a different manner (for example, with a delinquent peer group or other gang).

  15. Theoretical Borderlands: Using Multiple Theoretical Perspectives to Challenge Inequitable Power Structures in Student Development Theory

    ERIC Educational Resources Information Center

    Abes, Elisa S.

    2009-01-01

    This article is an exploration of possibilities and methodological considerations for using multiple theoretical perspectives in research that challenges inequitable power structures in student development theory. Specifically, I explore methodological considerations when partnering queer theory and constructivism in research on lesbian identity…

  16. Code-Switching during Parent-Child Reading Interactions: Taking Multiple Theoretical Perspectives

    ERIC Educational Resources Information Center

    Kabuto, Bobbie

    2010-01-01

    This article uses multiple theoretical perspectives to understand the synergy that occurs between linguistically diverse parents and children during reading interactions. Through the detailed analysis of code-switching during book-sharing activities in a middle-class, bilingual home, we can observe how linguistically diverse parents support the…

  17. Community, Collective or Movement? Evaluating Theoretical Perspectives on Network Building

    NASA Astrophysics Data System (ADS)

    Spitzer, W.

    2015-12-01

    Since 2007, the New England Aquarium has led a national effort to increase the capacity of informal science venues to effectively communicate about climate change. We are now leading the NSF-funded National Network for Ocean and Climate Change Interpretation (NNOCCI), partnering with the Association of Zoos and Aquariums, FrameWorks Institute, Woods Hole Oceanographic Institution, Monterey Bay Aquarium, and National Aquarium, with evaluation conducted by the New Knowledge Organization, Pennsylvania State University, and Ohio State University. NNOCCI enables teams of informal science interpreters across the country to serve as "communication strategists" - beyond merely conveying information they can influence public perceptions, given their high level of commitment, knowledge, public trust, social networks, and visitor contact. We provide in-depth training as well as an alumni network for ongoing learning, implementation support, leadership development, and coalition building. Our goals are to achieve a systemic national impact, embed our work within multiple ongoing regional and national climate change education networks, and leave an enduring legacy. What is the most useful theoretical model for conceptualizing the work of the NNOCCI community? This presentation will examine the pros and cons of three perspectives -- community of practice, collective impact, and social movements. The community of practice approach emphasizes use of common tools, support for practice, social learning, and organic development of leadership. A collective impact model focuses on defining common outcomes, aligning activities toward a common goal, structured collaboration. A social movement emphasizes building group identity and creating a sense of group efficacy. This presentation will address how these models compare in terms of their utility in program planning and evaluation, their fit with the unique characteristics of the NNOCCI community, and their relevance to our program goals.

  18. A theoretical perspective on road safety communication campaigns.

    PubMed

    Elvik, Rune

    2016-12-01

    This paper proposes a theoretical perspective on road safety communication campaigns, which may help in identifying the conditions under which such campaigns can be effective. The paper proposes that, from a theoretical point of view, it is reasonable to assume that road user behaviour is, by and large, subjectively rational. This means that road users are assumed to behave the way they think is best. If this assumption is accepted, the best theoretical prediction is that road safety campaigns consisting of persuasive messages only will have no effect on road user behaviour and accordingly no effect on accidents. This theoretical prediction is not supported by meta-analyses of studies that have evaluated the effects of road safety communication campaigns. These analyses conclude that, on the average, such campaigns are associated with an accident reduction. The paper discusses whether this finding can be explained theoretically. The discussion relies on the distinction made by many modern theorists between bounded and perfect rationality. Road user behaviour is characterised by bounded rationality. Hence, if road users can gain insight into the bounds of their rationality, so that they see advantages to themselves of changing behaviour, they are likely to do so. It is, however, largely unknown whether such a mechanism explains why some road safety communication campaigns have been found to be more effective than others.

  19. Heterogeneous reactions important in atmospheric ozone depletion: a theoretical perspective.

    PubMed

    Bianco, Roberto; Hynes, James T

    2006-02-01

    Theoretical studies of the mechanisms of several heterogeneous reactions involving ClONO(2), H(2)O, HCl, HBr, and H(2)SO(4) important in atmospheric ozone depletion are described, focused primarily on reactions on aqueous aerosol surfaces. Among the insights obtained is the active chemical participation of the surface water molecules in several of these reactions. The general methodology adopted allows reduction of these complex chemical problems to meaningful model systems amenable to quantum chemical calculations.

  20. Multistatic aerosol-cloud lidar in space: A theoretical perspective

    NASA Astrophysics Data System (ADS)

    Mishchenko, Michael I.; Alexandrov, Mikhail D.; Cairns, Brian; Travis, Larry D.

    2016-11-01

    Accurate aerosol and cloud retrievals from space remain quite challenging and typically involve solving a severely ill-posed inverse scattering problem. In this Perspective, we formulate in general terms an aerosol and aerosol-cloud interaction space mission concept intended to provide detailed horizontal and vertical profiles of aerosol physical characteristics as well as identify mutually induced changes in the properties of aerosols and clouds. We argue that a natural and feasible way of addressing the ill-posedness of the inverse scattering problem while having an exquisite vertical-profiling capability is to fly a multistatic (including bistatic) lidar system. We analyze theoretically the capabilities of a formation-flying constellation of a primary satellite equipped with a conventional monostatic (backscattering) lidar and one or more additional platforms each hosting a receiver of the scattered laser light. If successfully implemented, this concept would combine the measurement capabilities of a passive multi-angle multi-spectral polarimeter with the vertical profiling capability of a lidar; address the ill-posedness of the inverse problem caused by the highly limited information content of monostatic lidar measurements; address the ill-posedness of the inverse problem caused by vertical integration and surface reflection in passive photopolarimetric measurements; help relax polarization accuracy requirements; eliminate the need for exquisite radiative-transfer modeling of the atmosphere-surface system in data analyses; yield the day-and-night observation capability; provide direct characterization of ground-level aerosols as atmospheric pollutants; and yield direct measurements of polarized bidirectional surface reflectance. We demonstrate, in particular, that supplementing the conventional backscattering lidar with just one additional receiver flown in formation at a scattering angle close to 170° can dramatically increase the information content of the

  1. A Heated Debate: Theoretical Perspectives of Sexual Exploitation and Sex Work

    PubMed Central

    Gerassi, Lara

    2015-01-01

    The theoretical and often political framework of sexual exploitation and sex work among women is widely and enthusiastically debated among academic and legal scholars alike. The majority of theoretical literature in this area focuses on the macro perspective, while the micro-level perspective as to theory and causation remains sparse. This article provides a comprehensive overview of the philosophical, legal, and political perspectives pertaining to sexual exploitation of women and girls while addressing the subsequent controversies in the field. PMID:26834302

  2. Perspectives in active liquid crystals.

    PubMed

    Majumdar, Apala; Cristina, Marchetti M; Virga, Epifanio G

    2014-11-28

    Active soft matter is a young, growing field, with potential applications to a wide variety of systems. This Theme Issue explores this emerging new field by highlighting active liquid crystals. The collected contributions bridge theory to experiment, mathematical theories of passive and active nematics, spontaneous flows to defect dynamics, microscopic to continuum levels of description, spontaneous activity to biological activation. While the perspectives offered here only span a small part of this rapidly evolving field, we trust that they might provide the interested reader with a taste for this new class of non-equilibrium systems and their rich behaviour.

  3. Solar and stellar activity - The theoretical approach

    NASA Astrophysics Data System (ADS)

    Belvedere, G.

    1985-10-01

    The unified approach to understanding solar and stellar activity is examined. Stellar activity observations have stimulated theoretical work, mostly within the framework of the alpha-omega dynamo theory. A number of uncertainties and intrinsic limits in dynamo theory do still exist, and these are discussed together with alternative or complementary suggestions. The relevance is stressed of nonlinear problems in dynamo theory - magnetoconvection, growth and stability of flux tubes against magnetic buoyancy, hydromagnetic global dynamos - to improve the understanding of both small and large scale interaction of rotation, turbulent convection and magnetic fields, and the transition from the linear to the nonlinear regime. Recent dynamo models of stellar activity are critically reviewed regarding the dependence of activity indexes and cycles on rotation rate and spectral type. Open problems to be solved by future work are outlined.

  4. Teaching Medical Sociology through Film: Theoretical Perspectives and Practical Tools.

    ERIC Educational Resources Information Center

    Pescosolido, Bernice A.

    1990-01-01

    Urges that students change from dualistic or relativistic thinking toward a sociological perspective on health, illness, and healing. Discusses feature films and how they can be used as case studies on mental illness, death-dying, and the political economy of illness. Appends an annotated list of films. (NL)

  5. Cognition in Orienteering: Theoretical Perspectives and Methods of Study.

    ERIC Educational Resources Information Center

    Ottosson, Torgny

    1996-01-01

    Almost without exception, published studies on cognition in orienteering have adopted an information processing perspective involving dualism between objective and subjective worlds. An alternative, experiential framework focuses on the orienteer's conception of (or way of experiencing) the task to be accomplished, and on "affordances" (lines of…

  6. A new look at social support: a theoretical perspective on thriving through relationships.

    PubMed

    Feeney, Brooke C; Collins, Nancy L

    2015-05-01

    Close and caring relationships are undeniably linked to health and well-being at all stages in the life span. Yet the specific pathways through which close relationships promote optimal well-being are not well understood. In this article, we present a model of thriving through relationships to provide a theoretical foundation for identifying the specific interpersonal processes that underlie the effects of close relationships on thriving. This model highlights two life contexts through which people may potentially thrive (coping successfully with life's adversities and actively pursuing life opportunities for growth and development), it proposes two relational support functions that are fundamental to the experience of thriving in each life context, and it identifies mediators through which relational support is likely to have long-term effects on thriving. This perspective highlights the need for researchers to take a new look at social support by conceptualizing it as an interpersonal process with a focus on thriving.

  7. Hypnosis in the Treatment of Alcoholism: A Theoretical Perspective.

    ERIC Educational Resources Information Center

    Steffenhagen, R. A.

    1983-01-01

    Reviews the history and theory of alcoholism and hypnosis and proposes a theoretical model of alcholism based on self-esteem. Suggets that hypnosis may be an effective tool in the treatment of alcoholism with cure as the goal, and calls for more consistency in theory and practice. (JAC)

  8. Principles of Reform and Reforming Principal Training: A Theoretical Perspective.

    ERIC Educational Resources Information Center

    Bjork, Lars G.; Ginsberg, Rick

    1995-01-01

    Examines reform debates in educational administration training programs using a theoretical framework derived from Thomas Kuhn's notion of paradigm. Most administrator training programs in the United States are characterized as hybrid/preparadigm departments unlikely to undertake fundamental changes. Using a collaborative school leadership program…

  9. Tertiary Overschooling in Nigeria: Theoretical Perspectives and Cases

    ERIC Educational Resources Information Center

    Etuk, Grace Koko; Akpan, Eno Gabriel; Etuk, Etuk Nssien

    2012-01-01

    This paper views overschooling as conditions whereby people occupy job positions which are not optimal for their qualifications. The theoretical backings for the paper are the Human Capital, the equity and the two-factor theories of motivation and job satisfaction. Antecedents to overschooling which are mentioned include educational emphasis, the…

  10. Dynamics of Occupational and Educational Status Projections: A Theoretical Perspective.

    ERIC Educational Resources Information Center

    Kuvlesky, William P.

    The purpose of this paper is to develop a theoretical framework to describe and account for dynamic properties of status projection phenomena. The effort is limited in the main to consideration of occupational and educational status projections, and emphasis is given to the particular characteristics and attributes of the rural social milieu…

  11. A Sociocultural Perspective of Learning: Developing a New Theoretical Tenet

    ERIC Educational Resources Information Center

    Phan, Huy P.

    2012-01-01

    Explanation pertaining to individuals' cognitive development and learning approaches is a recurring theme in the areas of education and psychology. The work of Okagaki (e.g., Okagaki, 2001; Okagaki & Frensch, 1998), for example, has provided both theoretical and empirical insights into the structuring and situational positioning of individuals…

  12. Sexual systems and life history of barnacles: a theoretical perspective.

    PubMed

    Yamaguchi, Sachi; Charnov, Eric L; Sawada, Kota; Yusa, Yoichi

    2012-09-01

    Thoracican barnacles show one of the most diverse sexual systems in animals: hermaphroditism, dioecy (males and females), and androdioecy (males and hermaphrodites). In addition, when present, male barnacles are very small and are called "dwarf males". The diverse sexual systems and male dwarfism in this taxon have attracted both theoretical and empirical biologists. In this article, we review the theoretical studies on barnacles' sexual systems in the context of sex allocation and life history theories. We first introduce the sex allocation models by Charnov, especially in relation to the mating group size, and a new expansion of his models is also proposed. We then explain three studies by Yamaguchi et al., who have studied the interaction between sex allocation and life history in barnacles. These studies consistently showed that limited mating opportunity favors androdioecy and dioecy over hermaphroditism. In addition, other factors, such as rates of survival and availability of food, are also important. We discuss the importance of empirical studies testing these predictions and how empirical studies interact with theoretical constructs.

  13. Theoretical perspectives on public communication preparedness for terrorist attacks.

    PubMed

    Wray, Ricardo J; Kreuter, Matthew W; Jacobsen, Heather; Clements, Bruce; Evans, R Gregory

    2004-01-01

    The experience of federal health authorities in responding to the mailed anthrax attacks in the Fall of 2001 sheds light on the challenges of public information dissemination in emergencies. Lessons learned from the Fall of 2001 have guided more recent efforts related to crisis communication and preparedness goals. This article applies theories and evidence from the field of communication to provide an orientation to how public health communication can best contribute to the preparedness effort. This theoretical orientation provides a framework to systematically assess current recommendations for preparedness communication.

  14. Sensory stimulation: theoretical perspectives and the evidence for effectiveness.

    PubMed

    Giacino, J T

    1996-01-01

    The use of sensory stimulation (SS) to promote recovery from coma has enjoyed widespread acceptance in rehabilitation settings. This has occurred despite the paucity of research regarding its effectiveness as well as opposing viewpoints concerning its utility. The purpose of this article is to: (1) outline the theoretical basis underlying the arguments for and against the use of SS; and (2) to review representative studies on the effectiveness of SS using a scientific evidence-based classification system. It is suggested that few conclusions can be drawn regarding the efficacy of SS because of the lack of well-designed clinical studies on this subject. Consequently, it is incumbent upon clinicians to clearly present to family members the high degree of uncertainty associated with this form of treatment.

  15. A graph theoretical perspective of a drug abuse epidemic model

    NASA Astrophysics Data System (ADS)

    Nyabadza, F.; Mukwembi, S.; Rodrigues, B. G.

    2011-05-01

    A drug use epidemic can be represented by a finite number of states and transition rules that govern the dynamics of drug use in each discrete time step. This paper investigates the spread of drug use in a community where some users are in treatment and others are not in treatment, citing South Africa as an example. In our analysis, we consider the neighbourhood prevalence of each individual, i.e., the proportion of the individual’s drug user contacts who are not in treatment amongst all of his or her contacts. We introduce parameters α∗, β∗ and γ∗, depending on the neighbourhood prevalence, which govern the spread of drug use. We examine how changes in α∗, β∗ and γ∗ affect the system dynamics. Simulations presented support the theoretical results.

  16. Structural and Electronic Properties of Isolated Nanodiamonds: A Theoretical Perspective

    SciTech Connect

    Raty, J; Galli, G

    2004-09-09

    Nanometer sized diamond has been found in meteorites, proto-planetary nebulae and interstellar dusts, as well as in residues of detonation and in diamond films. Remarkably, the size distribution of diamond nanoparticles appears to be peaked around 2-5 nm, and to be largely independent of preparation conditions. Using ab-initio calculations, we have shown that in this size range nanodiamond has a fullerene-like surface and, unlike silicon and germanium, exhibit very weak quantum confinement effects. We called these carbon nanoparticles bucky-diamonds: their atomic structure, predicted by simulations, is consistent with many experimental findings. In addition, we carried out calculations of the stability of nanodiamond which provided a unifying explanation of its size distribution in extra-terrestrial samples, and in ultra-crystalline diamond films. Here we present a summary of our theoretical results and we briefly outline work in progress on doping of nanodiamond with nitrogen.

  17. The Ethics of Human Freedom and Healthcare Policy: A Nursing Theoretical Perspective.

    PubMed

    Milton, Constance L

    2015-07-01

    Global healthcare and healthcare policies are evolving with change at a swift pace. Inherent in the discussions of a person's right to choose health is the notion of freedom. The author in this column compares and contrasts bioethical views of freedom and autonomy with alternative views and possibilities by examining an ethic of freedom grounded from a different paradigm, the humanbecoming nursing theoretical perspective.

  18. Rural Development in the People's Republic of China: A Theoretical Perspective

    ERIC Educational Resources Information Center

    Flora, Cornelia Butler; Flora, Jan L.

    1977-01-01

    The article presents (1) a theoretical perspective describing rural development in the People's Republic of China which allows for generalization and comparison to the other developing rural settings, and (2) four conceptual systematic variables, a concrete policy variable, and a series of illustrative propositions linking them. (NQ)

  19. Denial of Chronic Illness and Disability: Part I. Theoretical, Functional, and Dynamic Perspectives

    ERIC Educational Resources Information Center

    Livneh, Hanoch

    2009-01-01

    Denial has been an integral part of the psychological and disability literature for more than 100 years. Yet, denial is an elusive concept and has been associated with mixed, indeed conflicting, theoretical perspectives, clinical strategies, and empirical findings. In this two-part article, the author provides an overview of the existing…

  20. "Through the Kaleidoscope": Intersections between Theoretical Perspectives and Classroom Implications in Critical Global Citizenship Education

    ERIC Educational Resources Information Center

    Eidoo, Sameena; Ingram, Leigh-Anne; MacDonald, Angela; Nabavi, Maryam; Pashby, Karen; Stille, Saskia

    2011-01-01

    This paper presents a multi-voiced examination of educating for global citizenship from critical, interdisciplinary perspectives. The paper explores how insights from theoretical work on multiculturalism, race, religion, gender, language and literacy, and eco-justice can contribute to a critical global citizenship education practice. It reports…

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

    ERIC Educational Resources Information Center

    Peterson, Susan K.

    2005-01-01

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

  2. Demystifying Gender Differences in Mentoring: Theoretical Perspectives and Challenges for Future Research on Gender and Mentoring

    ERIC Educational Resources Information Center

    Young, Angela M.; Cady, Steven; Foxon, Marguerite J.

    2006-01-01

    Issues of gender and mentoring are explored through several theoretical lenses--similarity-attraction paradigm, power dependence, social exchange, biological, and psychological theories--to provide a more comprehensive view of mentoring from a gender-based perspective. Issues related to gender and mentoring presented in past mentoring research and…

  3. Developing Doctoral Authors: Engaging with Theoretical Perspectives through the Literature Review

    ERIC Educational Resources Information Center

    Wisker, Gina

    2015-01-01

    The literature review is arguably the place in a thesis where doctoral authors convincingly engage with theory and theoretical perspectives underlying their research, situating their own contribution to knowledge in established and ongoing dialogues in the field. One difficulty doctoral candidates encounter in their learning to be researchers is…

  4. Theoretical Perspectives of Male Sexual Abuse: Conceptualization of a Case Study

    ERIC Educational Resources Information Center

    Diamanduros, Terry; Cosentino, Clare E.; Tysinger, P. Dawn; Tysinger, Jeffrey A.

    2012-01-01

    The purpose of this article is to demonstrate the traumatic impact that sexual abuse can have on a young male's development by addressing mediating dispositions that can render a child vulnerable to the effects of sexual abuse. Consideration is given to three different theoretical perspectives that are not exclusive to male victims but shed light…

  5. Historical Perspectives: Pioneering Definitions and Theoretical Positions in the Field of Gifted Education

    ERIC Educational Resources Information Center

    Jolly, Jennifer L.

    2005-01-01

    The previous Historical Perspectives column focused on the foundations of gifted education and the influence that Francis Galton, Alfred Binet, and Cesare Lombroso had in shaping the field. This work seeks to extend the examination of the historical roots of gifted education by focusing on definitions and theoretical underpinnings of giftedness…

  6. Nanoscale molecular communication networks: a game-theoretic perspective

    NASA Astrophysics Data System (ADS)

    Jiang, Chunxiao; Chen, Yan; Ray Liu, K. J.

    2015-12-01

    Currently, communication between nanomachines is an important topic for the development of novel devices. To implement a nanocommunication system, diffusion-based molecular communication is considered as a promising bio-inspired approach. Various technical issues about molecular communications, including channel capacity, noise and interference, and modulation and coding, have been studied in the literature, while the resource allocation problem among multiple nanomachines has not been well investigated, which is a very important issue since all the nanomachines share the same propagation medium. Considering the limited computation capability of nanomachines and the expensive information exchange cost among them, in this paper, we propose a game-theoretic framework for distributed resource allocation in nanoscale molecular communication systems. We first analyze the inter-symbol and inter-user interference, as well as bit error rate performance, in the molecular communication system. Based on the interference analysis, we formulate the resource allocation problem as a non-cooperative molecule emission control game, where the Nash equilibrium is found and proved to be unique. In order to improve the system efficiency while guaranteeing fairness, we further model the resource allocation problem using a cooperative game based on the Nash bargaining solution, which is proved to be proportionally fair. Simulation results show that the Nash bargaining solution can effectively ensure fairness among multiple nanomachines while achieving comparable social welfare performance with the centralized scheme.

  7. Metabolic engineering from a cybernetic perspective. 1. Theoretical preliminaries

    PubMed

    Varner; Ramkrishna

    1999-05-01

    The theoretical basis of a cybernetic metabolic network design and analysis framework, which has been subsequently successfully applied to predict system response to genetic alteration, is presented. This conceptual methodology consists of three main branches, namely, a model realization framework, a representation of genetic alteration, and lastly, a metabolic design component. These concepts are introduced as a series of postulates that describe the basic tenets of the approach. Each branch is discussed in turn, starting with the cybernetic representation of arbitrarily complex metabolic networks. A set of postulates is put forth that affords the modular construction of cybernetic models of metabolic networks using as a base a library of elementary pathways. This is followed by a discussion of the representation of genetic alterations within the cybernetic framework. It is postulated that the objective of the base network and the altered system are identical (at least on the time scale required for the organism to "learn" new objectives). This implies, with respect to resource allocation, that the base network and its genetically altered counterpart may still be treated as optimal systems; however, the set of competing physiological choices open to the altered network expands or contracts depending upon the nature of the genetic perturbation. Lastly, to add a predictive design aspect to the methodology, we present a set of postulates that outline the application of metabolic control analysis to cybernetic model systems. We postulate that sensitivity coefficients computed from a cybernetic model, although still local in scope, have the added benefit of a systematic representation of regulatory function as described by the cybernetic variables. Thus, information gained from sensitivity measurements stemming from a cybernetic model include the explicit input of metabolic regulation, a component that is lacking in a purely kinetic representation of metabolic function

  8. Changing theoretical perspectives on urbanisation in Asian developing countries.

    PubMed

    Lin, G C

    1994-02-01

    European models of urbanization inadequately capture the process of growth of urban cities in Asian developing countries. The following theoretical issues were presented as illustrations of the inadequacies of European paradigms: 1) the role of cities in regional development, 2) the dual nature of employment in Asian cities, 3) foreign investments, and 4) socialism. The concept of extended metropolitan regions in Asian countries was advanced by the studies of McGee and Ginsburg; metropolitan regions were recognized as unique to Asia. Socioeconomic development led to the blurring of regions into distinct urban and rural areas and to the mixing of agricultural and nonagricultural areas. The city-based model of economic concentration was replaced with a region-based urbanization. There is no universally applicable model of urban transition, although the influence of Euro-Americanism can still be felt in the theories of developing country development. What is not known is whether the new form of urban transition is a viable option or is a compromise between city-biased strategy and the development of intermediate and small towns. The effects of extended metropolitan regions are still unknown. Primary urbanization has its roots in early civilizations. Peterson developed the notions of the transitional stages of industrialization and urbanization: 1) preindustrial with high birth, death, and infant mortality rates of young, small populations; 2) early Western industrialization with reduced mortality and increased births; and 3) modern Western society with low birth and mortality rates and older, larger populations. Kingsley Davis provided the conception of rural-to-urban migration and urban growth, associated with urban economic and social opportunity and a shift from agricultural to nonagricultural employment. McGee postulated demographic, economic, and social transitions as part of the urbanization process. There is an increasing awareness that urban growth and the

  9. Theoretical perspectives of male sexual abuse: conceptualization of a case study.

    PubMed

    Diamanduros, Terry; Cosentino, Clare E; Tysinger, P Dawn; Tysinger, Jeffrey A

    2012-01-01

    The purpose of this article is to demonstrate the traumatic impact that sexual abuse can have on a young male's development by addressing mediating dispositions that can render a child vulnerable to the effects of sexual abuse. Consideration is given to three different theoretical perspectives that are not exclusive to male victims but shed light on the impact that sexual abuse can have on the development of a young boy. These perspectives include early family relationships and attachment theory, developmental psychopathology, and trauma theory. These theoretical lenses provide a conceptual understanding into why some victims are vulnerable to the effects of sexual abuse. Each theoretical view is applied to a case study of an adolescent male with a history of early trauma and sexual abuse. Clinical implications are discussed.

  10. Dealing with the multidimensionality of sustainability through the use of multiple perspectives - a theoretical framework

    NASA Astrophysics Data System (ADS)

    Lönngren, Johanna; Svanström, Magdalena; Ingerman, Åke; Holmberg, John

    2016-05-01

    The concept of perspectives is important in discussions about the multidimensionality of sustainability problems and the need to consider many different aspects when dealing with them. This paper aims to facilitate discussions among both educators and researchers about didactical approaches to developing students' abilities to deal with the multidimensionality of sustainability challenges through the use of multiple perspectives. For this purpose, a theoretical framework was developed that describes perspectives in terms of a set of general characteristics, as well as a number of ways in which students can develop and reflect on perspectives. Development of the framework was supported by a qualitative content analysis of transcripts from interviews with undergraduate engineering students in Sweden.

  11. Whole-body cryotherapy: empirical evidence and theoretical perspectives

    PubMed Central

    Bleakley, Chris M; Bieuzen, François; Davison, Gareth W; Costello, Joseph T

    2014-01-01

    Whole-body cryotherapy (WBC) involves short exposures to air temperatures below −100°C. WBC is increasingly accessible to athletes, and is purported to enhance recovery after exercise and facilitate rehabilitation postinjury. Our objective was to review the efficacy and effectiveness of WBC using empirical evidence from controlled trials. We found ten relevant reports; the majority were based on small numbers of active athletes aged less than 35 years. Although WBC produces a large temperature gradient for tissue cooling, the relatively poor thermal conductivity of air prevents significant subcutaneous and core body cooling. There is weak evidence from controlled studies that WBC enhances antioxidant capacity and parasympathetic reactivation, and alters inflammatory pathways relevant to sports recovery. A series of small randomized studies found WBC offers improvements in subjective recovery and muscle soreness following metabolic or mechanical overload, but little benefit towards functional recovery. There is evidence from one study only that WBC may assist rehabilitation for adhesive capsulitis of the shoulder. There were no adverse events associated with WBC; however, studies did not seem to undertake active surveillance of predefined adverse events. Until further research is available, athletes should remain cognizant that less expensive modes of cryotherapy, such as local ice-pack application or cold-water immersion, offer comparable physiological and clinical effects to WBC. PMID:24648779

  12. Unpacking teacher-researcher collaboration with three theoretical frameworks: a case of expansive learning activity?

    NASA Astrophysics Data System (ADS)

    Gade, Sharada

    2015-09-01

    Long association with a mathematics teacher at a Grade 4-6 school in Sweden, is basis for reporting a case of teacher-researcher collaboration. Three theoretical frameworks used to study its development over time are relational knowing, relational agency and cogenerative dialogue. While relational knowing uses narrative perspectives to explore the experiential and relational nature of collaboration; relational agency, draws on activity theory perspectives and identifies the change in the purpose of collaboration, from initially conducting classroom interventions to co-authoring research. Finally, cogenerative dialogue, deploys hermeneutic-phenomenological perspectives and investigates the dialogue that transpired between Lotta and the author, as they co-authored their research report. Such analysis sheds invaluable light on a case of expansive learning activity.

  13. Active Learning: Historical and Contemporary Perspectives.

    ERIC Educational Resources Information Center

    Page, Marilyn

    The purposes of the first two parts of this literature review are to clarify the concept of active learning and discuss the use and value of active learning models. In Part I, the perspectives of five historical proponents of active learning, Rousseau, Pestalozzi, Dewey, Kilpatrick, and Piaget, are discussed. The views of four contemporary…

  14. Ejection Fraction and ESPVR. A study from a theoretical perspective.

    PubMed

    Shoucri, Rachad M

    2013-01-01

    A formula derived by using large elastic deformation for the contraction of the myocardium is used to describe the pressure-volume relation (PVR) in the heart left ventricle, it is also used to calculate a mathematical expression for the non-linear end-systolic pressure-volume relation (ESPVR) in the left ventricle. An important feature of the mathematical formalism used is the inclusion of the isovolumic pressure Piso (equal active pressure generated by the myocardium) in the formalism describing the PVR. Relations between the ejection fraction (EF) and parameters describing the non-linear ESPVR are presented. It is shown that the non-linear ESPVR offers a rich collection of parameters that can be used to study the performance of the ventricles, like the areas under the ESPVR (units of energy) or the ordinates of the ESPVR (units of pressure), slopes and intercepts of the curves involved. The mathematical procedure can be easily implemented in a non-invasive way in routine clinical work when ratios of variables are calculated, it necessitates only the non-invasive measurement of the dimensions of the ventricles. Applications to clinical data published in the literature are presented, and they give results that show the consistency of the mathematical formalism used. The implications of the results of this research work on the study of the problem of heart failure with normal or preserved ejection fraction (HFpEF) are discussed.

  15. Swimming active droplet: A theoretical analysis

    NASA Astrophysics Data System (ADS)

    Schmitt, M.; Stark, H.

    2013-02-01

    Recently, an active microswimmer was constructed where a micron-sized droplet of bromine water was placed into a surfactant-laden oil phase. Due to a bromination reaction of the surfactant at the interface, the surface tension locally increases and becomes non-uniform. This drives a Marangoni flow which propels the squirming droplet forward. We develop a diffusion-advection-reaction equation for the order parameter of the surfactant mixture at the droplet interface using a mixing free energy. Numerical solutions reveal a stable swimming regime above a critical Marangoni number M but also stopping and oscillating states when M is increased further. The swimming droplet is identified as a pusher whereas in the oscillating state it oscillates between being a puller and a pusher.

  16. Emotion felt by the listener and expressed by the music: literature review and theoretical perspectives.

    PubMed

    Schubert, Emery

    2013-12-17

    In his seminal paper, Gabrielsson (2002) distinguishes between emotion felt by the listener, here: "internal locus of emotion" (IL), and the emotion the music is expressing, here: "external locus of emotion" (EL). This paper tabulates 16 comparisons of felt versus expressed emotions in music published in the decade 2003-2012 consisting of 19 studies/experiments and provides some theoretical perspectives. The key findings were that (1) IL rating was frequently rated statistically the same or lower than the corresponding EL rating (e.g., lower felt happiness rating compared to the apparent happiness of the music), and that (2) self-select and preferred music had a smaller gap across the emotion loci than experimenter-selected and disliked music. These key findings were explained by an "inhibited" emotional contagion mechanism, where the otherwise matching felt emotion may have been attenuated by some other factor such as social context. Matching between EL and IL for loved and self-selected pieces was explained by the activation of "contagion" circuits. Physiological arousal, personality and age, as well as musical features (tempo, mode, putative emotions) also influenced perceived and felt emotion distinctions. A variety of data collection formats were identified, but mostly using rating items. In conclusion, a more systematic use of terminology appears desirable. Two broad categories, namely matched and unmatched, are proposed as being sufficient to capture the relationships between EL and IL, instead of four categories as suggested by Gabrielsson.

  17. Emotion felt by the listener and expressed by the music: literature review and theoretical perspectives

    PubMed Central

    Schubert, Emery

    2013-01-01

    In his seminal paper, Gabrielsson (2002) distinguishes between emotion felt by the listener, here: “internal locus of emotion” (IL), and the emotion the music is expressing, here: “external locus of emotion” (EL). This paper tabulates 16 comparisons of felt versus expressed emotions in music published in the decade 2003–2012 consisting of 19 studies/experiments and provides some theoretical perspectives. The key findings were that (1) IL rating was frequently rated statistically the same or lower than the corresponding EL rating (e.g., lower felt happiness rating compared to the apparent happiness of the music), and that (2) self-select and preferred music had a smaller gap across the emotion loci than experimenter-selected and disliked music. These key findings were explained by an “inhibited” emotional contagion mechanism, where the otherwise matching felt emotion may have been attenuated by some other factor such as social context. Matching between EL and IL for loved and self-selected pieces was explained by the activation of “contagion” circuits. Physiological arousal, personality and age, as well as musical features (tempo, mode, putative emotions) also influenced perceived and felt emotion distinctions. A variety of data collection formats were identified, but mostly using rating items. In conclusion, a more systematic use of terminology appears desirable. Two broad categories, namely matched and unmatched, are proposed as being sufficient to capture the relationships between EL and IL, instead of four categories as suggested by Gabrielsson. PMID:24381565

  18. Mature students learning statistics: The activity theory perspective

    NASA Astrophysics Data System (ADS)

    Gordon, Sue

    1993-09-01

    The concept of approach "stresses relationships between intention, process and outcome within a specified context as described by an individual" (Schmeck, 1988, p. 10). This paper explores the approaches to learning of a group of mature students from the theoretical perspective of activity theory in order to gain an insight into some of the ways statistics is learned. In this framework, learning, regarded as goal-directed behaviour, is analysed by exploring the socio-historical factors relating to students' self regulation of their cognitive activities. The material is derived from questionnaires and interviews with five students, and focuses on the students' own interpretations of the contexts affecting their approaches.

  19. Testing a Theoretical Model of Immigration Transition and Physical Activity.

    PubMed

    Chang, Sun Ju; Im, Eun-Ok

    2015-01-01

    The purposes of the study were to develop a theoretical model to explain the relationships between immigration transition and midlife women's physical activity and test the relationships among the major variables of the model. A theoretical model, which was developed based on transitions theory and the midlife women's attitudes toward physical activity theory, consists of 4 major variables, including length of stay in the United States, country of birth, level of acculturation, and midlife women's physical activity. To test the theoretical model, a secondary analysis with data from 127 Hispanic women and 123 non-Hispanic (NH) Asian women in a national Internet study was used. Among the major variables of the model, length of stay in the United States was negatively associated with physical activity in Hispanic women. Level of acculturation in NH Asian women was positively correlated with women's physical activity. Country of birth and level of acculturation were significant factors that influenced physical activity in both Hispanic and NH Asian women. The findings support the theoretical model that was developed to examine relationships between immigration transition and physical activity; it shows that immigration transition can play an essential role in influencing health behaviors of immigrant populations in the United States. The NH theoretical model can be widely used in nursing practice and research that focus on immigrant women and their health behaviors. Health care providers need to consider the influences of immigration transition to promote immigrant women's physical activity.

  20. Defining Adapted Physical Activity: International Perspectives

    ERIC Educational Resources Information Center

    Hutzler, Yeshayahu; Sherrill, Claudine

    2007-01-01

    The purpose of this study was to describe international perspectives concerning terms, definitions, and meanings of adapted physical activity (APA) as (a) activities or service delivery, (b) a profession, and (c) an academic field of study. Gergen's social constructionism, our theory, guided analysis of multiple sources of data via qualitative…

  1. The relevance of postcolonial theoretical perspectives to research in Aboriginal health.

    PubMed

    Browne, Annette J; Smye, Victoria L; Varcoe, Colleen

    2005-12-01

    The authors critically examine the relevance of postcolonial theoretical perspectives to nursing research in the area of Aboriginal health. They discuss key theoretical underpinnings of postcolonial theory, citing differences and commonalities in postcolonial theory, postcolonial indigenous thinking, and other forms of critical theory. Drawing on insights from Aboriginal scholars, they critique the relevance of postcolonial discourses to issues of concern to Aboriginal peoples, and the potential limitations of those discourses. They then consider the implications of conducting research that is informed by postcolonial perspectives. They argue that postcolonial perspectives provide direction for research with Aboriginal communities in 4 interrelated ways. These are focused on (a) issues of partnership and "voice" in the research process, (b) a commitment to engaging in praxis-oriented inquiry, (c) understanding how continuities from the past shape the present context of health and health care, and (d) the colonizing potential of research. The authors draw attention to the concept of cultural safety as an instrument for incorporating postcolonial perspectives into the realm of nursing. To illustrate applications of postcolonial theory, they give examples from recent research conducted in partnership with Aboriginal communities. Although postcolonial theories are relatively new in nursing discourses, they provide a powerful analytical framework for considering the legacy of the colonial past and the neocolonial present as the context in which health care is delivered.

  2. INFRARED AND RAMAN VIBRATIONAL OPTICAL ACTIVITY: Theoretical and Experimental Aspects

    NASA Astrophysics Data System (ADS)

    Nafie, Laurence A.

    1997-10-01

    Advances in the field of vibrational optical activity (VOA) are reviewed over the past decade. Topics are surveyed with an emphasis on the theoretical and instrumental progress in both vibrational circular dichroism (VCD) and Raman optical activity (ROA). Applications of VOA to stereochemical and biological problems are reviewed, with a bias toward new kinds of experiments made possible by theoretical and instrumental advances. In the field of VCD, the most notable advances have taken place in the quality and size of ab initio calculations of VOA intensities and in the quality of step-scan Fourier transform instrumentation. For ROA, the most dramatic progress has occurred in the areas of theoretical formulation and high-throughput instrumentation. Applications of VOA now include all major classes of biological and pharmaceutical molecules. VOA's importance as a diagnostic tool will likely grow as the control of molecular chirality increases in research and industrial areas.

  3. Perspectives on the Contribution of Social Science to Adapted Physical Activity: Looking Forward, Looking Back

    ERIC Educational Resources Information Center

    Causgrove Dunn, Janice; Cairney, John; Zimmer, Chantelle

    2016-01-01

    In this article, we reflect on the contributions of the social sciences to the field of adapted physical activity by examining the theories and methods that have been adopted from the social science disciplines. To broaden our perspective on adapted physical activity and provide new avenues for theoretical and empirical exploration, we discuss and…

  4. Characterization of Linearly Separable Boolean Functions: A Graph-Theoretic Perspective.

    PubMed

    Rao, Yanyi; Zhang, Xianda

    2016-04-05

    In this paper, we present a novel approach for studying Boolean function in a graph-theoretic perspective. In particular, we first transform a Boolean function f of n variables into an induced subgraph Hf of the n-dimensional hypercube, and then, we show the properties of linearly separable Boolean functions on the basis of the analysis of the structure of Hf. We define a new class of graphs, called hyperstar, and prove that the induced subgraph Hf of any linearly separable Boolean function f is a hyperstar. The proposal of hyperstar helps us uncover a number of fundamental properties of linearly separable Boolean functions in this paper.

  5. Semiotic and Theoretic Control in Argumentation and Proof Activities

    ERIC Educational Resources Information Center

    Arzarello, Ferdinando; Sabena, Cristina

    2011-01-01

    We present a model to analyze the students' activities of argumentation and proof in the graphical context of Elementary Calculus. The theoretical background is provided by the integration of Toulmin's structural description of arguments, Peirce's notions of sign, diagrammatic reasoning and abduction, and Habermas' model for rational behavior.…

  6. 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…

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

    PubMed Central

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

    2015-01-01

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

  8. Time perspective and physical activity among central Appalachian adolescents.

    PubMed

    Gulley, Tauna

    2013-04-01

    Time perspective is a cultural behavioral concept that reflects individuals' orientations or attitudes toward the past, present, or future. Individuals' time perspectives influence their choices regarding daily activities. Time perspective is an important consideration when teaching adolescents about the importance of being physically active. However, little is known about the relationship between time perspective and physical activity among adolescents. The purpose of this study was to determine the time perspective of central Appalachian adolescents and explore the relationship between time perspective and physical activity. This study was guided by The theory of planned behavior (TPB). One hundred and ninety-three students completed surveys to examine time perspective and physical activity behaviors. Data were collected in one school. Results of this study can inform school nurses and high school guidance counselors about the importance of promoting a future-oriented time perspective to improve physical activity and educational outcomes.

  9. Time Perspective and Physical Activity among Central Appalachian Adolescents

    ERIC Educational Resources Information Center

    Gulley, Tauna

    2013-01-01

    Time perspective is a cultural behavioral concept that reflects individuals' orientations or attitudes toward the past, present, or future. Individuals' time perspectives influence their choices regarding daily activities. Time perspective is an important consideration when teaching adolescents about the importance of being physically active.…

  10. Toward a unifying model of identification with groups: integrating theoretical perspectives.

    PubMed

    Roccas, Sonia; Sagiv, Lilach; Schwartz, Shalom; Halevy, Nir; Eidelson, Roy

    2008-08-01

    Building on the contributions of diverse theoretical approaches, the authors present a multidimensional model of group identification. Integrating conceptions from the social identity perspective with those from research on individualism-collectivism, nationalism- patriotism, and identification with organizations, we propose four conceptually distinct modes of identification: importance (how much I view the group as part of who I am), commitment (how much I want to benefit the group), superiority (how much I view my group as superior to other groups), and deference (how much I honor, revere, and submit to the group's norms, symbols, and leaders). We present an instrument for assessing the four modes of identification and review initial empirical findings that validate the proposed model and show its utility in understanding antecedents and consequences of identification.

  11. New Chemistry for Artificial Photosynthesis: A Theoretical Perspective (448th Brookhaven Lecture)

    SciTech Connect

    Muckerman, James

    2009-04-15

    Photosynthesis, which occurs in green plants, is a natural process in which light produces energy from water and carbon dioxide. Nowadays, scientists are working to replicate this process artificially, with the goal of creating clean, usable, renewable energy from the greenhouse gas carbon dioxide. During the 448th Brookhaven Lecture in Berkner Hall on Wednesday, April 15, at 4 p.m., Senior Chemist James Muckerman of the Chemistry Department will discuss "New Chemistry for Artificial Photosynthesis: A Theoretical Perspective." After reviewing natural photosynthesis, he will discuss how electrochemical systems driven by sunlight could carry out artificial photosynthesis and how these systems could then be turned into usable fuels that do not create pollution or undesirable by-products

  12. Social Learning in MMOG: An Activity Theoretical Perspective

    ERIC Educational Resources Information Center

    Ang, Chee Siang; Zaphiris, Panayiotis

    2008-01-01

    Purpose: Recently, researchers have begun investigating the learning process that occurs within computer games (learning to play), as opposed to studying games that support explicit learning for educational purposes (playing to learn). With the increasing popularity of massively multiplayer online games (MMOGs), some research has begun to look…

  13. Designing effective human-automation-plant interfaces: a control-theoretic perspective.

    PubMed

    Jamieson, Greg A; Vicente, Kim J

    2005-01-01

    In this article, we propose the application of a control-theoretic framework to human-automation interaction. The framework consists of a set of conceptual distinctions that should be respected in automation research and design. We demonstrate how existing automation interface designs in some nuclear plants fail to recognize these distinctions. We further show the value of the approach by applying it to modes of automation. The design guidelines that have been proposed in the automation literature are evaluated from the perspective of the framework. This comparison shows that the framework reveals insights that are frequently overlooked in this literature. A new set of design guidelines is introduced that builds upon the contributions of previous research and draws complementary insights from the control-theoretic framework. The result is a coherent and systematic approach to the design of human-automation-plant interfaces that will yield more concrete design criteria and a broader set of design tools. Applications of this research include improving the effectiveness of human-automation interaction design and the relevance of human-automation interaction research.

  14. Building Social Capital through the Use of an Appreciative Inquiry Theoretical Perspective in a School and University Partnership

    ERIC Educational Resources Information Center

    Calabrese, Raymond L.

    2006-01-01

    Purpose: The purpose of this paper is to explore the ecology of collaboration between school and university partners using an appreciative inquiry theoretical perspective and to demonstrate how it enhances the social capital in school and university partnerships. Design/methodology/approach: A case study of a partnership of an inner-city high…

  15. The Meaning of Quality Professional Learning for School Improvement: Articulating a Coherent Vision Rooted in a Theoretical Perspective on Learning

    ERIC Educational Resources Information Center

    Lancer, Jared R.

    2015-01-01

    A clearly articulated theoretical perspective on learning is essential for developing consistency among learning, pedagogy, and leadership and for planning and making adjustments to better serve students in all areas. Notwithstanding, few professional learning and school improvement approaches in pre-school through 12th grade (P-12) schools…

  16. The critical perspective in psychological jurisprudence theoretical advances and epistemological assumptions.

    PubMed

    Arrigo, Bruce A

    2002-01-01

    The critical perspectives of psychological jurisprudence identified above, along with their corresponding epistemological assumptions, reflect a radical agenda for change at the law-psychology divide. Although not exhaustively reviewed, the individual theories represent different approaches by which structural reform can be enacted and citizen well-being can therefore be realized. Collectively, the critical perspectives and their attending presuppositions challenge conventional wisdom about prospects for transforming (i.e., humanizing) the legal apparatus. I submit that the future viability of the law-psychology movement, and its overall utility for society, considerably depends on its capacity to facilitate and secure such widespread change. By focusing on critical theoretical inquiry, this article makes painfully clear that much of what is wrong with the legal system, especially in its interactions with and interpretations of people, cannot be amended or solved through it. Indeed, as Roesch (1995) observed, "changes in the justice system will never be sufficient to create a just society, nor will within system changes by themselves ever have much of an impact on individuals who come into conflict with the law" (p. 3). I agree. Accordingly, it is time to move on and, where necessary, to look elsewhere for guidance. The radical agenda in psychological jurisprudence represents a provocative strategy, providing a meaningful basis for critique and a sustainable basis for reform. Both are integral to the call for justice embodied in the founding of the AP-LS decades ago. Realizing this challenge, however, remains an unfulfilled dream. Thus, the task that awaits is to apply the insights of critical psychological jurisprudence to relevant areas of research and policy. I submit that the academy can ill afford to dismiss this task. Indeed, in the final analysis, to do so would not only defer prospects for justice but would destroy its very possibility, especially for

  17. Theoretical considerations for mapping activation in human cardiac fibrillation

    NASA Astrophysics Data System (ADS)

    Rappel, Wouter-Jan; Narayan, Sanjiv M.

    2013-06-01

    Defining mechanisms for cardiac fibrillation is challenging because, in contrast to other arrhythmias, fibrillation exhibits complex non-repeatability in spatiotemporal activation but paradoxically exhibits conserved spatial gradients in rate, dominant frequency, and electrical propagation. Unlike animal models, in which fibrillation can be mapped at high spatial and temporal resolution using optical dyes or arrays of contact electrodes, mapping of cardiac fibrillation in patients is constrained practically to lower resolutions or smaller fields-of-view. In many animal models, atrial fibrillation is maintained by localized electrical rotors and focal sources. However, until recently, few studies had revealed localized sources in human fibrillation, so that the impact of mapping constraints on the ability to identify rotors or focal sources in humans was not described. Here, we determine the minimum spatial and temporal resolutions theoretically required to detect rigidly rotating spiral waves and focal sources, then extend these requirements for spiral waves in computer simulations. Finally, we apply our results to clinical data acquired during human atrial fibrillation using a novel technique termed focal impulse and rotor mapping (FIRM). Our results provide theoretical justification and clinical demonstration that FIRM meets the spatio-temporal resolution requirements to reliably identify rotors and focal sources for human atrial fibrillation.

  18. [Music in health promotion and therapeutic practice. Cultural, theoretical and clinical perspectives.

    PubMed

    Mastnak, Wolfgang

    2016-12-01

    Music can serve as a shelter and music therapy can provide spaces for symbolic experience and the modification of behavioural and cognitive patterns. Explaining the power of music, ancient theories speak of an analogy between music and man. Similar views are also found in modern music therapy such as Sound Work, a voice-body-based model. Complementary to the aspect of analogy, the principle of transformation is of vital importance, such as the transitions between the five elements, the solid organs and the pentatonic scale in Chinese music therapy, for instance. Distinct modes of matter-mind-transitions define the theoretical framework of neuro-psychologically based music therapy. A triadic model encompassing neuro-endocrine, psychological and aesthetic facets explains the preventive and therapeutic effect of music in stress-associated disorders and burnout. Finally, a new voice-based model (Arion Psychovocal Therapy) is presented. Integrating anthropological theories, anatomical perspectives of movement, and artistic features it focuses on psychiatry, psycho-prevention, and public health and highlights the interdisciplinary nature of music in medicine.

  19. A cultural historical theoretical perspective of discourse and design in the science classroom

    NASA Astrophysics Data System (ADS)

    Adams, Megan

    2015-06-01

    Flavio Azevedo, Peggy Martalock and Tugba Keser have initiated an important conversation in science education as they use sociocultural theory to introduce design based scenarios into the science classroom. This response seeks to expand Azevedo, Martalock and Keser's article The discourse of design- based science classroom activities by using a specific perspective within a sociocultural framework. Through using a cultural historical (Vygotsky in The history and development of higher mental functions, Plenum Press, New York, 1987) reading of design based activity and discourse in the science classroom, it is proposed that learning should be an integral part of these processes. Therefore, everyday and scientific concepts are explained and expanded in relation to Inventing Graphing and discourse presented in Azevedo, Martalock and Keser's article. This response reports on the importance of teacher's being explicit in relation to connecting everyday and scientific concepts alongside design based activity and related science concepts when teaching students. It is argued that explicit teaching of concepts should be instigated prior to analysis of discourse in the science classroom as it is only with experience and understanding these processes that students have the resources to call upon to argue like practicing scientists.

  20. Experimental and Theoretical Studies on Biologically Active Lanthanide (III) Complexes

    NASA Astrophysics Data System (ADS)

    Kostova, I.; Trendafilova, N.; Georgieva, I.; Rastogi, V. K.; Kiefer, W.

    2008-11-01

    The complexation ability and the binding mode of the ligand coumarin-3-carboxylic acid (HCCA) to La(III), Ce(III), Nd(III), Sm(III), Gd(III) and Dy(III) lanthanide ions (Ln(III)) are elucidated at experimental and theoretical level. The complexes were characterized using elemental analysis, DTA and TGA data as well as 1H NMR and 13C NMR spectra. FTIR and Raman spectroscopic techniques as well as DFT quantum chemical calculations were used for characterization of the binding mode and the structures of lanthanide(III) complexes of HCCA. The metal—ligand binding mode is predicted through molecular modeling and energy estimation of different Ln—CCA structures using B3LYP/6-31G(d) method combined with a large quasi-relativistic effective core potential for lanthanide ion. The energies obtained predict bidentate coordination of CCA- to Ln(III) ions through the carbonylic oxygen and the carboxylic oxygen. Detailed vibrational analysis of HCCA, CCA- and Ln(III) complexes based on both calculated and experimental frequencies confirms the suggested metal—ligand binding mode. The natural bonding analysis predicts strongly ionic character of the Ln(III)-CCA bonding in the- complexes studied. With the relatively resistant tumor cell line K-562 we obtained very interesting in-vitro results which are in accordance with our previously published data concerning the activity of lanthanide(III) complexes with other coumarin derivatives.

  1. Dioxygen activation in methane monooxygenase: a theoretical study.

    PubMed

    Gherman, Benjamin F; Baik, Mu-Hyun; Lippard, Stephen J; Friesner, Richard A

    2004-03-10

    Using broken-symmetry unrestricted Density Functional Theory, the mechanism of enzymatic dioxygen activation by the hydroxylase component of soluble methane monooxygenase (MMOH) is determined to atomic detail. After a thorough examination of mechanistic alternatives, an optimal pathway was identified. The diiron(II) state H(red) reacts with dioxygen to give a ferromagnetically coupled diiron(II,III) H(superoxo) structure, which undergoes intersystem crossing to the antiferromagnetic surface and affords H(peroxo), a symmetric diiron(III) unit with a nonplanar mu-eta(2):eta(2)-O(2)(2)(-) binding mode. Homolytic cleavage of the O-O bond yields the catalytically competent intermediate Q, which has a di (mu-oxo)diiron(IV) core. A carboxylate shift involving Glu243 is essential to the formation of the symmetric H(peroxo) and Q structures. Both thermodynamic and kinetic features agree well with experimental data, and computed spin-exchange coupling constants are in accord with spectroscopic values. Evidence is presented for pH-independent decay of H(red) and H(peroxo). Key electron-transfer steps that occur in the course of generating Q from H(red) are also detailed and interpreted. In contrast to prior theoretical studies, a requisite large model has been employed, electron spins and couplings have been treated in a quantitative manner, potential energy surfaces have been extensively explored, and quantitative total energies have been determined along the reaction pathway.

  2. Textbook Questions in Context-Based and Traditional Chemistry Curricula Analysed from a Content Perspective and a Learning Activities Perspective

    ERIC Educational Resources Information Center

    Overman, Michelle; Vermunt, Jan D.; Meijer, Paulien C.; Bulte, Astrid M. W.; Brekelmans, Mieke

    2013-01-01

    In this study, questions in context-based and traditional chemistry textbooks were analysed from two perspectives that are at the heart of chemistry curricula reforms: a content perspective and a learning activities perspective. To analyse these textbook questions, we developed an instrument for each perspective. In total, 971 textbook questions…

  3. Active disturbance rejection control: methodology and theoretical analysis.

    PubMed

    Huang, Yi; Xue, Wenchao

    2014-07-01

    The methodology of ADRC and the progress of its theoretical analysis are reviewed in the paper. Several breakthroughs for control of nonlinear uncertain systems, made possible by ADRC, are discussed. The key in employing ADRC, which is to accurately determine the "total disturbance" that affects the output of the system, is illuminated. The latest results in theoretical analysis of the ADRC-based control systems are introduced.

  4. Maximizing Wellness in Successful Aging and Cancer Coping: The Importance of Family Communication from a Socioemotional Selectivity Theoretical Perspective.

    PubMed

    Fisher, Carla L; Nussbaum, Jon F

    Interpersonal communication is a fundamental part of being and key to health. Interactions within family are especially critical to wellness across time. Family communication is a central means of adaptation to stress, coping, and successful aging. Still, no theoretical argument in the discipline exists that prioritizes kin communication in health. Theoretical advances can enhance interventions and policies that improve family life. This article explores socioemotional selectivity theory (SST), which highlights communication in our survival. Communication partner choice is based on one's time perspective, which affects our prioritization of goals to survive-goals sought socially. This is a first test of SST in a family communication study on women's health and aging. More than 300 women of varying ages and health status participated. Two time factors, later adulthood and late-stage breast cancer, lead women to prioritize family communication. Findings provide a theoretical basis for prioritizing family communication issues in health reform.

  5. Unpacking Teacher-Researcher Collaboration with Three Theoretical Frameworks: A Case of Expansive Learning Activity?

    ERIC Educational Resources Information Center

    Gade, Sharada

    2015-01-01

    Long association with a mathematics teacher at a Grade 4-6 school in Sweden, is basis for reporting a case of teacher-researcher collaboration. Three theoretical frameworks used to study its development over time are relational knowing, relational agency and cogenerative dialogue. While relational knowing uses narrative perspectives to explore the…

  6. Going forward through the world: thinking theoretically about first person perspective digital ethnography.

    PubMed

    Pink, Sarah

    2015-06-01

    Engaging first person perspective recording as a type of digital ethnography invites the question of how we might understand the status of the knowledge it produces. To examine this question I will focus on how first person perspective camera recordings might be engaged and made analytically meaningful in disciplines where naturalistic and observational visual recording is uncommon and where the idea of producing naturalistic or optimally objective visual recordings of people's lives is problematized. In doing so I explore the wider possibilities of these technologies for ethnographic research both beyond their existing uses and for interdisciplinary research where the images they produce might be analysed from more than one perspective.

  7. Cancer surviving patients' rehabilitation - understanding failure through application of theoretical perspectives from Habermas.

    PubMed

    Mikkelsen, Thorbjørn H; Soendergaard, Jens; Jensen, Anders B; Olesen, Frede

    2008-06-06

    This study aims to analyze whether the rehabilitation of cancer surviving patients (CSPs) can be better organized. The data for this paper consists of focus group interviews (FGIs) with CSPs, general practitioners (GPs) and hospital physicians. The analysis draws on the theoretical framework of Jürgen Habermas, utilizing his notions of 'the system and the life world' and 'communicative and strategic action'. In Habermas' terminology, the social security system and the healthcare system are subsystems that belong to what he calls the 'system', where actions are based on strategic actions activated by the means of media such as money and power which provide the basis for other actors' actions. The social life, on the other hand, in Habermas' terminology, belongs to what he calls the 'life world', where communicative action is based on consensual coordination among individuals. Our material suggests that, within the hospital world, the strategic actions related to diagnosis, treatment and cure in the biomedical discourse dominate. They function as inclusion/exclusion criteria for further treatment. However, the GPs appear to accept the CSPs' previous cancer diagnosis as a precondition sufficient for providing assistance. Although the GPs use the biomedical discourse and often give biomedical examples to exemplify rehabilitation needs, they find psychosocial aspects, so-called lifeworld aspects, to be an important component of their job when helping CSPs. In this way, they appear more open to communicative action in relation to the CSPs' lifeworld than do the hospital physicians. Our data also suggests that the CSPs' lifeworld can be partly colonized by the system during hospitalization, making it difficult for CSPs when they are discharged at the end of treatment. This situation seems to be crucial to our understanding of why CSPs often feel left in limbo after discharge. We conclude that the distinction between the system and the lifeworld and the implications of a

  8. Cancer surviving patients' rehabilitation – understanding failure through application of theoretical perspectives from Habermas

    PubMed Central

    Mikkelsen, Thorbjørn H; Soendergaard, Jens; Jensen, Anders B; Olesen, Frede

    2008-01-01

    This study aims to analyze whether the rehabilitation of cancer surviving patients (CSPs) can be better organized. The data for this paper consists of focus group interviews (FGIs) with CSPs, general practitioners (GPs) and hospital physicians. The analysis draws on the theoretical framework of Jürgen Habermas, utilizing his notions of 'the system and the life world' and 'communicative and strategic action'. In Habermas' terminology, the social security system and the healthcare system are subsystems that belong to what he calls the 'system', where actions are based on strategic actions activated by the means of media such as money and power which provide the basis for other actors' actions. The social life, on the other hand, in Habermas' terminology, belongs to what he calls the 'life world', where communicative action is based on consensual coordination among individuals. Our material suggests that, within the hospital world, the strategic actions related to diagnosis, treatment and cure in the biomedical discourse dominate. They function as inclusion/exclusion criteria for further treatment. However, the GPs appear to accept the CSPs' previous cancer diagnosis as a precondition sufficient for providing assistance. Although the GPs use the biomedical discourse and often give biomedical examples to exemplify rehabilitation needs, they find psychosocial aspects, so-called lifeworld aspects, to be an important component of their job when helping CSPs. In this way, they appear more open to communicative action in relation to the CSPs' lifeworld than do the hospital physicians. Our data also suggests that the CSPs' lifeworld can be partly colonized by the system during hospitalization, making it difficult for CSPs when they are discharged at the end of treatment. This situation seems to be crucial to our understanding of why CSPs often feel left in limbo after discharge. We conclude that the distinction between the system and the lifeworld and the implications of a

  9. First isolated active titanium peroxo complex: characterization and theoretical study.

    PubMed

    Kholdeeva, Oxana A; Trubitsina, Tatiana A; Maksimovskaya, Raisa I; Golovin, Anatolii V; Neiwert, Wade A; Kolesov, Boris A; López, Xavier; Poblet, Josep M

    2004-04-05

    The protonated titanium peroxo complex [Bu(4)N](4)[HPTi(O(2))W(11)O(39)] (1) has been first prepared via interaction of the micro-oxo dimeric heteropolytungstate [Bu(4)N](8)[(PTiW(11)O(39))(2)O] (3) with an excess of 30% aqueous H(2)O(2) in MeCN. Peroxo complex 1 has been characterized by using elemental analysis, UV-vis, IR, resonance Raman (RR), (31)P and (183)W NMR spectroscopy, cyclic voltammetry, and potentiometric titration. The electronic and vibrational spectra of 1 are very similar to those of the well-known unprotonated titanium peroxo complex [Bu(4)N](5)[PTi(O(2))W(11)O(39)] (2), while (31)P and (183)W NMR spectra differ significantly. A compilation of the physicochemical techniques supports a monomeric Keggin type structure of 1 bearing one peroxo ligand attached to Ti(IV) in a eta(2)-coordination mode. The protonation of the titanium peroxo complex results in an increase of the redox potential of the peroxo group, E(1/2) = 1.25 and 0.88 V relative to Ag/AgCl reference electrode for 1 and 2, respectively. In contrast to 2, 1 readily reacts with 2,3,6-trimethylphenol (TMP) at 40 degrees C in MeCN to give 2,2',3,3',5,5'-hexamethyl-4,4'-biphenol (BP) and 2,3,5-trimethyl-p-benzoquinone (TMBQ). The proportion between BP and TMBQ in the reaction products depends on the TMP/1 ratio. When a 2-fold excess of TMP is used, the main reaction product is BP (90%), while using a 2-fold excess of 1 leads to TMBQ (95%). On the basis of the product study, a homolytic oxidation mechanism that implicates the formation of phenoxyl radicals is suggested. The RR deuterium labeling experiments show that the activating proton is most likely localized at a Ti-O-W bridging oxygen rather than at the peroxo group. Theoretical calculations carried out at the DFT level on the protonated and unprotonated titanium peroxo derivatives also propose that the most stable complex is formed preferentially after protonation of the Ti-O-W site; however, both Ti-OH-W and TiOO-H protonated anions

  10. Synchronous brain activity across individuals underlies shared psychological perspectives

    PubMed Central

    Lahnakoski, Juha M.; Glerean, Enrico; Jääskeläinen, Iiro P.; Hyönä, Jukka; Hari, Riitta; Sams, Mikko; Nummenmaa, Lauri

    2014-01-01

    For successful communication, we need to understand the external world consistently with others. This task requires sufficiently similar cognitive schemas or psychological perspectives that act as filters to guide the selection, interpretation and storage of sensory information, perceptual objects and events. Here we show that when individuals adopt a similar psychological perspective during natural viewing, their brain activity becomes synchronized in specific brain regions. We measured brain activity with functional magnetic resonance imaging (fMRI) from 33 healthy participants who viewed a 10-min movie twice, assuming once a ‘social’ (detective) and once a ‘non-social’ (interior decorator) perspective to the movie events. Pearson's correlation coefficient was used to derive multisubject voxelwise similarity measures (inter-subject correlations; ISCs) of functional MRI data. We used k-nearest-neighbor and support vector machine classifiers as well as a Mantel test on the ISC matrices to reveal brain areas wherein ISC predicted the participants' current perspective. ISC was stronger in several brain regions—most robustly in the parahippocampal gyrus, posterior parietal cortex and lateral occipital cortex—when the participants viewed the movie with similar rather than different perspectives. Synchronization was not explained by differences in visual sampling of the movies, as estimated by eye gaze. We propose that synchronous brain activity across individuals adopting similar psychological perspectives could be an important neural mechanism supporting shared understanding of the environment. PMID:24936687

  11. Can Inner Experience Be Apprehended in High Fidelity? Examining Brain Activation and Experience from Multiple Perspectives

    PubMed Central

    Hurlburt, Russell T.; Alderson-Day, Ben; Fernyhough, Charles; Kühn, Simone

    2017-01-01

    We discuss the historical context for explorations of “pristine inner experience,” attempts to apprehend and describe the inner experiences that directly present themselves in natural environments. There is no generally accepted method for determining whether such apprehensions/descriptions should be considered high fidelity. By analogy from musical recording, we present and discuss one strategy for establishing experiential fidelity: the examining of brain activation associated with a variety of experiential perspectives that had not been specified at the time of data collection. We beeped participants in an fMRI scanner at randomly-determined times and recorded time-locked brain activations. We used Descriptive Experience Sampling (DES) to apprehend and describe the participant's experience that was ongoing at each beep. These apprehensions/descriptions were obtained with no specific theoretical perspective or experimental intention when originally collected. If these apprehensions/descriptions were of high fidelity, then these pairings of moments of experience and brain activations should be able to be productively examined and re-examined in multiple ways and from multiple theoretical perspectives. We discuss a small set of such re-examinations and conclude that this strategy is worthy of further examination. PMID:28191000

  12. Theoretical Perspectives on Learning for the Prevention of Fishing Vessel Accidents.

    ERIC Educational Resources Information Center

    Boshier, Roger

    2000-01-01

    Outlines a theoretical model for accident prevention education that includes four paradigms: humanism, radical humanism, functionalism, and radical functionalism. Applies the model to fishing boat accidents and derives implications for changing the content and processes of prevention education. (SK)

  13. Cognitive Structures of the Gifted: Theoretical Perspectives, Factor Analysis, Triarchic Theories of Intelligence, and Insight Issues.

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.

    The paper reviews research on the cognitive structures of gifted students. Theories of R. Sternberg and his triarchic model of intelligence are described. Sternberg asserts that three processes appear to account for insight: selective encoding, selective combination, and selective comparison. H. Gardner's perspective citing six types of…

  14. Studies on Written Corrective Feedback: Theoretical Perspectives, Empirical Evidence, and Future Directions

    ERIC Educational Resources Information Center

    Wang, Ting; Jiang, Lin

    2015-01-01

    The role of written corrective feedback (WCF) in the process of acquiring a second language (L2) has been an issue of considerable controversies over past decades. This article intends to provide a critical review of the increasing number of WCF studies thus far and to inspire new perspectives for future research. It starts by briefly tracing the…

  15. Experiential Learning: A Theoretical Critique from Five Perspectives. Information Series No. 385.

    ERIC Educational Resources Information Center

    Fenwick, Tara J.

    This monograph presents an overview of experiential learning from five perspectives. Following a history of experiential learning in 20th century adult education, the essay first offers a summary of the reflective constructivist view of experiential learning. The constructivist approach is taken by educators seeking to enhance the process of adult…

  16. Toward an Interdisciplinary Perspective: A Review of Adult Learning Frameworks and Theoretical Models of Motor Learning

    ERIC Educational Resources Information Center

    Roessger, Kevin M.

    2012-01-01

    Researchers have yet to agree on an approach that supports how adults best learn novel motor skills in formal educational contexts. The literature fails to adequately discuss adult motor learning from the standpoint of adult education. Instead, the subject is addressed by other disciplines. This review attempts to integrate perspectives across…

  17. Dealing with the Multidimensionality of Sustainability through the Use of Multiple Perspectives--A Theoretical Framework

    ERIC Educational Resources Information Center

    Lönngren, Johanna; Svanström, Magdalena; Ingerman, Åke; Holmberg, John

    2016-01-01

    The concept of perspectives is important in discussions about the multidimensionality of sustainability problems and the need to consider many different aspects when dealing with them. This paper aims to facilitate discussions among both educators and researchers about didactical approaches to developing students' abilities to deal with the…

  18. Chapter 2. General theoretical perspectives of narrative analysis of substance use-related dependency.

    PubMed

    Larsson, Sam; Lilja, John; von Braun, Therese; Sjöblom, Yvonne

    2013-11-01

    This chapter provides a short introduction to, and an overview for, using narrative analysis in the understanding of the use and misuse of alcohol and drugs. Important theoretical and methodological dimensions are discussed. Some tentative conclusions, limitations, and unresolved critical issues concerning the use of narrative research methods in the analysis of substance use-related dependency problems are also presented.

  19. Criteria for Continuing Professional Development of Technology Teachers' Professional Knowledge: A Theoretical Perspective

    ERIC Educational Resources Information Center

    Engelbrecht, Werner; Ankiewicz, Piet

    2016-01-01

    Continuing professional teacher development (CPTD) is generally accepted as an indispensable tool for the professional development of technology teachers. The current theoretical framework for CPTD comprises a variety of models. However, criteria underpinning these models are not explicit. If, in turn, the criteria were explicit, it could serve as…

  20. The Government-Higher Education Institution Relationship: Theoretical Considerations from the Perspective of Agency Theory

    ERIC Educational Resources Information Center

    Kivisto, Jussi

    2005-01-01

    This article introduces the agency theory to the field of higher education research. By applying agency theory to the inter-organisational relationship between government and higher education institutions, it is possible to illustrate general problems facing control and governance in a more theoretical and analytical way. The conceptual arsenal…

  1. Corrective Feedback in L2 Writing: Theoretical Perspectives, Empirical Insights, and Future Directions

    ERIC Educational Resources Information Center

    Van Beuningen, Catherine

    2010-01-01

    The role of (written) corrective feedback (CF) in the process of acquiring a second language (L2) has been an issue of considerable controversy among theorists and researchers alike. Although CF is a widely applied pedagogical tool and its use finds support in SLA theory, practical and theoretical objections to its usefulness have been raised…

  2. Deconstructing Theoretical Perspectives and Practice in Education Sector Intervention in Africa

    ERIC Educational Resources Information Center

    Omwami, Edith Mukudi

    2011-01-01

    This work examines the congruence and incongruence in policy and practice in education sector development effort for Africa. The focus is on the role of human agency in defining policy and practice. The UNESCO (United Nations Educational, Scientific and Cultural Organization) put the theoretical orientations that have been used to explain the…

  3. Soft X-ray spectroscopy of transition metal compounds: a theoretical perspective

    NASA Astrophysics Data System (ADS)

    Bokarev, S. I.; Hilal, R.; Aziz, S. G.; Kühn, O.

    2016-12-01

    To date, X-ray spectroscopy has become a routine tool that can reveal highly local and element-specific information on the electronic structure of atoms in complex environments. Here, we report on the development of an efficient and versatile theoretical methodology for the treatment of soft X-ray spectra of transition metal compounds based on the multi-configurational self-consistent field electronic structure theory. A special focus is put on the L-edge photon-in/photon-out and photon-in/electron-out processes, i.e. X-ray absorption, resonant inelastic scattering, partial fluorescence yield, and photoelectron spectroscopy, all treated on the same theoretical footing. The investigated systems range from small prototypical coordination compounds and catalysts to aggregates of biomolecules.

  4. Physical Activity at Daycare: Issues, Challenges and Perspectives

    ERIC Educational Resources Information Center

    van Zandvoort, Melissa; Tucker, Patricia; Irwin, Jennifer D.; Burke, Shauna M.

    2010-01-01

    This study sought to examine London, Ontario-based childcare providers' perspectives of the barriers and facilitators to physical activity participation among preschoolers (i.e. children aged 2.5-5 years) attending daycare. A heterogeneous sample of childcare providers (n = 54; response rate 47%) working at public daycare facilities in London,…

  5. Exploring Patient Activation in the Clinic: Measurement from Three Perspectives

    ERIC Educational Resources Information Center

    Ledford, Christy J. W.; Ledford, Christopher C.; Childress, Marc A.

    2013-01-01

    Objective. To further conceptualize and operationalize patient activation (PA), using measures from patient, physician, and researcher perspectives. Data Source/Study Setting. Multimethod observation in 2010 within a family medicine clinic. Study Design. Part of an intervention with 130 patients with type 2 diabetes, this observational study…

  6. Physical Activity Promotion in Call Centres: Employers' Perspectives

    ERIC Educational Resources Information Center

    Renton, Sheila J.; Lightfoot, Nancy E.; Maar, Marion A.

    2011-01-01

    This study followed a predominantly qualitative approach to explore the perspectives of employers in Sudbury, Ontario, Canada, call centres (CCs) regarding physical activity (PA) promotion in workplaces, by identifying current practices and employers' motivation to promote PA, as well as perceived facilitators and barriers. In-depth interviews…

  7. Perspectives of Aacademic Activities in Universities in Pakistan

    ERIC Educational Resources Information Center

    Ali, Akhtar; Tariq, Riaz H.; Topping, Keith J.

    2013-01-01

    The article explores perspectives on academic activities in public sector universities in Pakistan. Seven Pakistani universities yielded 290 teachers and 568 students in the sample. Factor analysis indicated five main factors in both teacher and student data sets. Both teachers and students were dissatisfied with the performance of the…

  8. Theoretical, spectral characterization and antineoplastic activity of new lanthanide complexes.

    PubMed

    Kostova, Irena; Trendafilova, Natasha; Momekov, Georgi

    2008-01-01

    The new cerium(III), lanthanum(III) and neodymium(III) complexes were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, (1)H NMR, (13)C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinates to the metal ion through both deprotonated hydroxyl groups, however participation of the carbonyl groups in the coordination to the metal ion was also suggested. Geometry optimization of 3,3'-(ortho-pyridinomethylene)di-[4-hydroxycoumarin] H(2)(o-pyhc), (H(2)L) and its dianionic forms, o-pyhc(2-), (L(2-)) were carried out at AM1 and PM3 levels as well as using density functional theory with Becke's three parameter hybrid method and correlation functional of Lee, Yang and Parr (B3LYP) with 6-31G(d) basis set. The optimized geometries of the neutral ligand isomers were stabilized by two asymmetrical intramolecular O-H...O hydrogen bonds (HBs). The conformational search showed four low-energy dianionic species (o-pyhc(2-)) on the potential energy surface. Molecular electrostatic potential calculations showed that the most preferred sites for electrophilic attack in H(2)(o-pyhc) and o-pyhc(2-) are the carbonyl oxygen atoms. The evaluation of the cytotoxic activity of the novel lantanide complexes on HL-60 myeloid cells revealed, that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum, and neodymium species, the latter being the least active. Taken together our data give us a reason to conclude that the newly synthesized lanthanide complexes should be a subset to further more detailed pharmacological and toxicological evaluation.

  9. Phil Wallace and Theoretical Physics at McGill in the 1950's: A Personal Perspective

    SciTech Connect

    Jackson, John David

    2010-11-18

    In 1946 Philip (Phil) Russell Wallace joined the Mathematics Department of McGill University as an Associate Professor of Applied Mathematics, apparently because A. H. S. Gillson, Dean of Arts and Science, wanted theoretical physicists to be in the Mathematics Department. He came with the dream of creating a theoretical physics group at McGill. By the spring of 1949, Phil was authorized to recruit two junior faculty in Mathematics. He hired Theodore (Ted) F. Morris from U. Toronto, who joined in September 1949, and me, who came in January 1950. The group had begun. Phil Wallace was born in Toronto in 1915 and grew up there. He entered the University of Toronto in 1933, earned a B.A. in mathematics in 1937, a M.A. in 1938, and a Ph.D. in applied mathematics in 1940 under Leopold Infeld. His Ph.D. thesis in general relativity was entitled 'On the relativistic equations of motion in electromagnetic theory.' In 1940 World War II had engulfed Europe and was having its effect on Canada, but the US was still at peace. L. J. Synge, Head of the Applied Mathematics Department at Toronto, told Wallace that people such as he would be needed in war work, but things were not ready quite yet. Hold yourself ready. Phil took a two-year position as lecturer in mathematics at the University of Cincinnati (1940-42); in the fall of 1942 he became a lecturer in mathematics at M.I.T. It was from there that he was recruited by Synge to join the war effort from 1943 to 1946 at N.R.C.'s Montreal Laboratory, the genesis of the Canadian Atomic Energy Project. Phil has described those heady wartime years in these pages. Much of the effort of the theoretical physicists was on nuclear reactor theory and the properties of relevant materials, such as graphite, under long and intense neutron bombardment. In late 1945 Phil was sent for four months to Bristol to learn about the properties of graphite from the esteemed N. F. Mott. This exposure led Phil to a life-long interest in graphite and in

  10. "Letting Go": From Ancient to Modern Perspectives on Relinquishing Personal Control-A Theoretical Perspective on Religion and Coping with Cancer.

    PubMed

    Merluzzi, Thomas V; Philip, Errol J

    2017-02-06

    The concept of "letting go" or relinquishing control has a long intellectual history, including the earliest Taoist writings, long-standing religious traditions, modern conceptualizations of religious coping, and current psychological control theory. This paper briefly traces the ancient roots of "letting go," with an emphasis on Stoic philosophers, and plants it firmly in current control theory and religious coping research, with a focus on its more modern conceptualization, that of secondary control. Presenting the theoretical perspective, which is grounded in religious conceptions of control of outcomes integrated with modern control theory in psychology, is the main goal of this paper. However, the theoretical integration is bolstered by some initial descriptive findings based on cancer patients and survivors. This integration of religious coping and psychological theory has important implications for testing the utility of personal control and God-referenced control as ways to cope with the uncertainties of a serious illness such as cancer. Finally, the theory and descriptive findings lay the groundwork for future empirical studies and the development of counseling interventions.

  11. [Obesity prevention from physical activity: from theoretical discourse to practice].

    PubMed

    Moreno, L A; Gracia-Marco, L

    2012-08-01

    Childhood obesity has increased considerably in most countries in recent years. Obese children already have many co-morbidities since infancy, which can have serious consequences in adulthood. From a health standpoint, the most appropriate to address this problem is primary prevention. This article aims to summarize the relevant aspects from the point of view of prevention of childhood obesity, and in particular to those related to physical activity. To this end, health and education professionals have a role. In all cases, it is necessary to perform the evaluation of programs to see if they are really effective. Developing new programs should be based on previous experiences that had positive results. As most interventions to date have not been very effective, much more research is needed in this area in the future.

  12. A theoretical study on cellular antioxidant activity of selected flavonoids

    NASA Astrophysics Data System (ADS)

    Rong, Yuzhi; Wang, Zhengwu; Wu, Jinhong; Zhao, Bo

    The antioxidant capacities of the selected flavonoids quercetin, luteolin and taxifolin have been investigated at density functional level of theory with the aim of verifying the cellular antioxidant activity (CAA) values representative of experimental findings. The selected flavonoids were believed to act through the H-atom transfer mechanism. Their potentiality of hydrogen abstraction was evaluated by computing the Osbnd H bond dissociation enthalpy (BDE) in gas-phase and in dimethylsulfoxide solution. Results indicate that the order of antioxidant efficacies calculated in this work is in agreement with that reported by experimental results of CAA. Time-dependent density functional theory (TDDFT) calculations were also performed both in gas-phase and in dimethylsulfoxide to reproduce the electronic UV-vis spectra of the selected flavonoids.

  13. Observational and Theoretical Constraints on Plume Activity at Europa

    NASA Astrophysics Data System (ADS)

    Nimmo, F.; Pappalardo, R.; Cuzzi, J.

    2007-12-01

    The recently-detected plume activity on Enceladus [1] has raised the question of whether Europa, too, might be active. The few Galileo images devoted to searches for plumes yielded no detections; comparisons between Voyager and Galileo images suggest that less than ~1mm of resurfacing has happened in the past 20 years over lengthscales of a few km [2]. Cassini observations of Europa's oxygen torus [3] suggest a column abundance and loss rate roughly consistent with modelled O sputtering rates [4,5]. However, the tenuous atmosphere does appear to be spatially non- uniform [6]. The observations suggest that plumes or other non-sputtering sources produce vapour at rates less than roughly 10~kg/s, or less than 10% of the Enceladus plume rate [1]. One possible source of vapour on Europa is shear heating [7,8]. For nominal Europa parameters the predicted rate of vapour production is roughly 1~kg/s per km of fault and the vapour exit velocity is ~450~m/s, much less than Europa's escape velocity. These results suggest that the bulk of the vapour will reimpact the surface after forming a plume approximately 70~km high. The resulting thermal anomaly due to vapour recondensation is ~2~K. To generate a total vapour production rate of 10~kg/s requires roughly 10~km of active faults. If there is a single plume, the local resurfacing rate is ~0.05~mm/yr, compatible with the observational resurfacing constraints [2]. Using a global lineament map [9] and assuming equi-spaced active faults, areas predicted to show most intense shear heating are two regions near the S pole (at ~90° and ~270° longitude) and one smaller patch near the N pole at ~270°. Shear heating, in addition to vapour production, may also cause elevated surface temperatures resulting in thermal segregation of ice [10]. These predictions may be compared with existing observations from Galileo, Cassini, and Earth-based telescopes [e.g. 6], and may assist in the planning of potential future spacecraft missions. [1

  14. Density functional reactivity theory study of SN2 reactions from the information-theoretic perspective.

    PubMed

    Wu, Zemin; Rong, Chunying; Lu, Tian; Ayers, Paul W; Liu, Shubin

    2015-10-28

    As a continuation of our recent efforts to quantify chemical reactivity with quantities from the information-theoretic approach within the framework of density functional reactivity theory, the effectiveness of applying these quantities to quantify electrophilicity for the bimolecular nucleophilic substitution (SN2) reactions in both gas phase and aqueous solvent is presented in this work. We examined a total of 21 self-exchange SN2 reactions for the compound with the general chemical formula of R1R2R3C-F, where R1, R2, and R3 represent substituting alkyl groups such as -H, -CH3, -C2H5, -C3H7, and -C4H9 in both gas and solvent phases. Our findings confirm that scaling properties for information-theoretic quantities found elsewhere are still valid. It has also been verified that the barrier height has the strongest correlation with the electrostatic interaction, but the contributions from the exchange-correlation and steric effects, though less significant, are indispensable. We additionally unveiled that the barrier height of these SN2 reactions can reliably be predicted not only by the Hirshfeld charge and information gain at the regioselective carbon atom, as previously reported by us for other systems, but also by other information-theoretic descriptors such as Shannon entropy, Fisher information, and Ghosh-Berkowitz-Parr entropy on the same atom. These new findings provide further insights for the better understanding of the factors impacting the chemical reactivity of this vastly important category of chemical transformations.

  15. Limits in the evolution of biological form: a theoretical morphologic perspective

    PubMed Central

    McGhee, George R.

    2015-01-01

    Limits in the evolution of biological form can be empirically demonstrated by using theoretical morphospace analyses, and actual analytic examples are given for univalved ammonoid shell form, bivalved brachiopod shell form and helical bryozoan colony form. Limits in the evolution of form in these animal groups can be shown to be due to functional and developmental constraints on possible evolutionary trajectories in morphospace. Future evolutionary-limit research is needed to analyse the possible existence of temporal constraint in the evolution of biological form on Earth, and in the search for the possible existence of functional alien life forms on Titan and Triton that are developmentally impossible for Earth life. PMID:26640645

  16. Common liability to addiction and “gateway hypothesis”: Theoretical, empirical and evolutionary perspective

    PubMed Central

    Vanyukov, Michael M.; Tarter, Ralph E.; Kirillova, Galina P.; Kirisci, Levent; Reynolds, Maureen D.; Kreek, Mary Jeanne; Conway, Kevin P.; Maher, Brion S.; Iacono, William G.; Bierut, Laura; Neale, Michael C.; Clark, Duncan B.; Ridenour, Ty A.

    2013-01-01

    Background Two competing concepts address the development of involvement with psychoactive substances: the “gateway hypothesis” (GH) and common liability to addiction (CLA). Method The literature on theoretical foundations and empirical findings related to both concepts is reviewed. Results The data suggest that drug use initiation sequencing, the core GH element, is variable and opportunistic rather than uniform and developmentally deterministic. The association between risks for use of different substances, if any, can be more readily explained by common underpinnings than by specific staging. In contrast, the CLA concept is grounded in genetic theory and supported by data identifying common sources of variation in the risk for specific addictions. This commonality has identifiable neurobiological substrate and plausible evolutionary explanations. Conclusions Whereas the “gateway” hypothesis does not specify mechanistic connections between “stages”, and does not extend to the risks for addictions, the concept of common liability to addictions incorporates sequencing of drug use initiation as well as extends to related addictions and their severity, provides a parsimonious explanation of substance use and addiction co-occurrence, and establishes a theoretical and empirical foundation to research in etiology, quantitative risk and severity measurement, as well as targeted non-drug-specific prevention and early intervention. PMID:22261179

  17. Perspectives of activated carbonpast, present and future

    SciTech Connect

    Carrubba, R.V.; Urbanic, J.E.; Wagner, N.J.; Zanitsch, R.H.

    1984-01-01

    Granular activated carbon has evolved a unique role as a broad spectrum solid adsorbent in its 75 years of commercial utilization. Creative applications development has established it as technology of choice for critical water purification, sweetener decolorization, air purification and solvent recovery applications, among others. New innovations in pressure swing adsorption and new vapor phase adsorbents promise equally significant future applications.

  18. Discussing Active Learning from the Practitioner's Perspective

    ERIC Educational Resources Information Center

    Bamba, Priscilla

    2015-01-01

    The purpose of this paper is to present an overview of how active learning took place in a class containing specific readings,cooperative and collaborative group work, and a writing assignment for college students at a Northern Virginia Community College campus (NVCC). Requisite knowledge, skills, learner characteristics, brain-based learning, and…

  19. A social neuroscience perspective on physical activity.

    PubMed

    Hall, Peter A; Elias, Lorin J; Fong, Geoffrey T; Harrison, Amabilis H; Borowsky, Ron; Sarty, Gordon E

    2008-08-01

    The objective of this investigation was to examine the cognitive characteristics of individuals who demonstrate successful and unsuccessful self-regulation of physical activity behavior. In Study 1, participants articulated 1-week intentions for physical activity and wore a triaxial accelerometer over the subsequent 7 days. Among those who were motivated to increase their physical activity, those who were most and least successful were administered an IQ test. In Study 2, a second sample of participants completed the same protocol and a smaller subset of matched participants attended a functional imaging (fMRI) session. In Study 1, successful self-regulators (SSRs) scored significantly higher than unsuccessful self-regulators (USRs) on a test of general cognitive ability, and this difference could not be accounted for by favorability of attitudes toward physical activity or conscientiousness. In Study 2, the IQ effect was replicated, with SSRs showing a full standard deviation advantage over USRs. In the imaging protocol, USRs showed heavier recruitment of cognitive resources relative to SSRs in the anterior cingulate and orbitofrontal cortex during performance of a Stroop task; SSRs showed heavier recruitment in the right dorsolateral prefrontal cortex.

  20. Planning and studying improvement in patient care: the use of theoretical perspectives.

    PubMed

    Grol, Richard P T M; Bosch, Marije C; Hulscher, Marlies E J L; Eccles, Martin P; Wensing, Michel

    2007-01-01

    A consistent finding in articles on quality improvement in health care is that change is difficult to achieve. According to the research literature, the majority of interventions are targeted at health care professionals. But success in achieving change may be influenced by factors other than those relating to individual professionals, and theories may help explain whether change is possible. This article argues for a more systematic use of theories in planning and evaluating quality-improvement interventions in clinical practice. It demonstrates how different theories can be used to generate testable hypotheses regarding factors that influence the implementation of change, and it shows how different theoretical assumptions lead to different quality-improvement strategies.

  1. The dynamics of health care reform--learning from a complex adaptive systems theoretical perspective.

    PubMed

    Sturmberg, Joachim P; Martin, Carmel M

    2010-10-01

    Health services demonstrate key features of complex adaptive systems (CAS), they are dynamic and unfold in unpredictable ways, and unfolding events are often unique. To better understand the complex adaptive nature of health systems around a core attractor we propose the metaphor of the health care vortex. We also suggest that in an ideal health care system the core attractor would be personal health attainment. Health care reforms around the world offer an opportunity to analyse health system change from a complex adaptive perspective. At large health care reforms have been pursued disregarding the complex adaptive nature of the health system. The paper details some recent reforms and outlines how to understand their strategies and outcomes, and what could be learnt for future efforts, utilising CAS principles. Current health systems show the inherent properties of a CAS driven by a core attractor of disease and cost containment. We content that more meaningful health systems reform requires the delicate task of shifting the core attractor from disease and cost containment towards health attainment.

  2. Quality of care from the patients' perspective: from theoretical concept to a new measuring instrument

    PubMed Central

    Sixma, Herman J.; Kerssens, Jan J.; van Campen, Crétien; Peters, Loe

    2002-01-01

    Introduction Patient views on quality of care are of paramount importance with respect to the implementation of quality assurance (QA) and improvement (QI) programmes. However, the relevance of patient satisfaction studies is often questioned because of conceptual and methodological problems. Here, it is our belief that a different strategy is necessary. Objective To develop a conceptual framework for measuring quality of care seen through the patients' eyes, based on the existing literature on consumer satisfaction in health care and business research. Results Patient or consumer satisfaction is regarded as a multidimensional concept, based on a relationship between experiences and expectations. However, where most health care researchers tend to concentrate on the result, patient (dis)satisfaction, a more fruitful approach is to look at the basic components of the concept: expectations (or `needs') and experiences. A conceptual framework – based on the sequence performance, importance, impact – and quality judgements of different categories of patients derived from importance and performance scores of different health care aspects, is elaborated upon and illustrated with empirical evidence. Conclusions The new conceptual model, with quality of care indices derived from importance and performance scores, can serve as a framework for QA and QI programmes from the patients' perspective. For selecting quality of care aspects, a category‐specific approach is recommended including the use of focus group discussions. PMID:11281863

  3. BK channel activators and their therapeutic perspectives

    PubMed Central

    Bentzen, Bo H.; Olesen, Søren-Peter; Rønn, Lars C. B.; Grunnet, Morten

    2014-01-01

    The large conductance calcium- and voltage-activated K+ channel (KCa1.1, BK, MaxiK) is ubiquitously expressed in the body, and holds the ability to integrate changes in intracellular calcium and membrane potential. This makes the BK channel an important negative feedback system linking increases in intracellular calcium to outward hyperpolarizing potassium currents. Consequently, the channel has many important physiological roles including regulation of smooth muscle tone, neurotransmitter release and neuronal excitability. Additionally, cardioprotective roles have been revealed in recent years. After a short introduction to the structure, function and regulation of BK channels, we review the small organic molecules activating BK channels and how these tool compounds have helped delineate the roles of BK channels in health and disease. PMID:25346695

  4. Perspectives on Biologically Active Camptothecin Derivatives

    PubMed Central

    Liu, Ying-Qian; Li, Wen-Qun; Morris-Natschke, Susan L.; Qian, Keduo; Yang, Liu; Zhu, Gao-Xiang; Wu, Xiao-Bing; Chen, An-Liang; Zhang, Shao-Yong; Song, Zi-Long; Lee, Kuo-Hsiung

    2015-01-01

    Camptothecins (CPTs) are cytotoxic natural alkaloids that specifically target DNA topoisomerase I. Research on CPTs has undergone a significant evolution from the initial discovery of CPT in the late 1960s through the study of synthetic small molecule derivatives to investigation of macromolecular constructs and formulations. Over the past years, intensive medicinal chemistry efforts have generated numerous CPT derivatives. Three derivatives, topotecan, irinotecan, and belotecan, are currently prescribed as anticancer drugs, and several related compounds are now in clinical trials. Interest in other biological effects, besides anticancer activity, of CPTs is also growing exponentially, as indicated by the large number of publications on the subject during the last decades. Therefore, the main focus of the present review is to provide an ample but condensed overview on various biological activities of CPT derivatives, in addition to continued up-to-date coverage of anticancer effects. PMID:25808858

  5. Designing m-learning for junior registrars--activation of a theoretical model of clinical knowledge.

    PubMed

    Kanstrup, Anne Marie; Boye, Niels; Nøhr, Christian

    2007-01-01

    The MINI-project aims at supporting junior registrars in the learning process of how to utilize their theoretical knowledge from Medical School in everyday clinical reasoning and practice. Due to the nature of the work--concurrent moving, learning and producing--we designed an m-learning application. This paper introduces the possibilities and challenges for design of the m-learning application based on a) analytical findings on learning and mobility as derived from the design case--an emergency medical ward b) theoretical perspectives on medical knowledge, and c) presentation of the design of an m-learning application. The design process was based on user-driven innovation and the paper discusses considerations on how to combine user-drive and generic models.

  6. Electrochemically modulated liquid chromatography: Theoretical investigations and applications from the perspectives of chromatography and interfacial electrochemistry

    SciTech Connect

    Keller, David W.

    2005-01-01

    Electrochemically modulated liquid chromatography (EMLC) employs a conductive material as both a stationary phase for chromatographic separations and as a working electrode for performing electrochemistry experiments. This dual functionality gives EMLC the capacity to manipulate chromatographic separations by changing the potential applied (Eapp) to the stationary phase with respect to an external reference. The ability to monitor retention as a function of Eapp provides a means to chromatographically monitor electrosorption processes at solid-liquid interfaces. In this dissertation, the retention mechanism for EMLC is examined from the perspective of electrical double layer theory and interfacial thermodynamics. From the chromatographic data, it is possible to determine the interfacial excess (Λ) of a solute and changes in interfacial tension (dγ) as a function of both Eapp and the supporting electrolyte concentration. Taken together, these two experimentally manipulated parameters can be examined within the context of the Gibbs adsorption equation to delineate the contribution of a variety of interfacial properties, including the charge of solute on the stationary phase and the potential of zero charge (PZC), to the mechanism behind EMLC-based retention. The chromatographic probing of interfacial phenomena is complemented by electroanalytical experiments that exploit the ability to monitor the electronic current flowing through an EMLC column. Cyclic voltammetry and chronoamperometry of an EMLC column are used to determine the electronic performance characteristics of an EMLC column. An electrochemical flow injection analysis of a column is provided in which the current required to maintain a constant Eapp is monitored and provides a way to examine the influence that acetonitrile and supporting electrolyte composition, flow rate, column backpressure, and ionic strength have on the structure of electrified interfaces.

  7. More than a face: a unified theoretical perspective on nonverbal social cue processing in social anxiety

    PubMed Central

    Gilboa-Schechtman, Eva; Shachar-Lavie, Iris

    2013-01-01

    Processing of nonverbal social cues (NVSCs) is essential to interpersonal functioning and is particularly relevant to models of social anxiety. This article provides a review of the literature on NVSC processing from the perspective of social rank and affiliation biobehavioral systems (ABSs), based on functional analysis of human sociality. We examine the potential of this framework for integrating cognitive, interpersonal, and evolutionary accounts of social anxiety. We argue that NVSCs are uniquely suited to rapid and effective conveyance of emotional, motivational, and trait information and that various channels are differentially effective in transmitting such information. First, we review studies on perception of NVSCs through face, voice, and body. We begin with studies that utilized information processing or imaging paradigms to assess NVSC perception. This research demonstrated that social anxiety is associated with biased attention to, and interpretation of, emotional facial expressions (EFEs) and emotional prosody. Findings regarding body and posture remain scarce. Next, we review studies on NVSC expression, which pinpointed links between social anxiety and disturbances in eye gaze, facial expressivity, and vocal properties of spontaneous and planned speech. Again, links between social anxiety and posture were understudied. Although cognitive, interpersonal, and evolutionary theories have described different pathways to social anxiety, all three models focus on interrelations among cognition, subjective experience, and social behavior. NVSC processing and production comprise the juncture where these theories intersect. In light of the conceptualizations emerging from the review, we highlight several directions for future research including focus on NVSCs as indexing reactions to changes in belongingness and social rank, the moderating role of gender, and the therapeutic opportunities offered by embodied cognition to treat social anxiety. PMID:24427129

  8. More than a face: a unified theoretical perspective on nonverbal social cue processing in social anxiety.

    PubMed

    Gilboa-Schechtman, Eva; Shachar-Lavie, Iris

    2013-12-31

    Processing of nonverbal social cues (NVSCs) is essential to interpersonal functioning and is particularly relevant to models of social anxiety. This article provides a review of the literature on NVSC processing from the perspective of social rank and affiliation biobehavioral systems (ABSs), based on functional analysis of human sociality. We examine the potential of this framework for integrating cognitive, interpersonal, and evolutionary accounts of social anxiety. We argue that NVSCs are uniquely suited to rapid and effective conveyance of emotional, motivational, and trait information and that various channels are differentially effective in transmitting such information. First, we review studies on perception of NVSCs through face, voice, and body. We begin with studies that utilized information processing or imaging paradigms to assess NVSC perception. This research demonstrated that social anxiety is associated with biased attention to, and interpretation of, emotional facial expressions (EFEs) and emotional prosody. Findings regarding body and posture remain scarce. Next, we review studies on NVSC expression, which pinpointed links between social anxiety and disturbances in eye gaze, facial expressivity, and vocal properties of spontaneous and planned speech. Again, links between social anxiety and posture were understudied. Although cognitive, interpersonal, and evolutionary theories have described different pathways to social anxiety, all three models focus on interrelations among cognition, subjective experience, and social behavior. NVSC processing and production comprise the juncture where these theories intersect. In light of the conceptualizations emerging from the review, we highlight several directions for future research including focus on NVSCs as indexing reactions to changes in belongingness and social rank, the moderating role of gender, and the therapeutic opportunities offered by embodied cognition to treat social anxiety.

  9. Therapeutic perspectives of epigenetically active nutrients.

    PubMed

    Remely, M; Lovrecic, L; de la Garza, A L; Migliore, L; Peterlin, B; Milagro, F I; Martinez, A J; Haslberger, A G

    2015-06-01

    Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction.

  10. Therapeutic perspectives of epigenetically active nutrients

    PubMed Central

    Remely, M; Lovrecic, L; de la Garza, A L; Migliore, L; Peterlin, B; Milagro, F I; Martinez, A J; Haslberger, A G

    2015-01-01

    Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction. PMID:25046997

  11. Tip-induced deformation of a phospholipid bilayer: Theoretical perspective of sum frequency generation imaging

    SciTech Connect

    Volkov, Victor

    2014-10-21

    The paper addresses theory of Sum Frequency Generation imaging of an atomic force microscopy tip-induced deformation of a bilayer phospholipid membrane deposited over a pore: known as a nano-drum system. Image modeling employed nonlinearities of the normal modes specific to hydrocarbon terminal methyls, which are distributed about the deformed surfaces of inner and outer leaflets. The deformed profiles are according to the solutions of shape equation for Canham-Helfrich Hamiltonian accounting properties of four membranes, which differ in elasticity and adhesion. The results indicate that in continuous deformed surfaces, the difference in the curvature of the outer and inner leaflets dominates in the imaged nonlinearity. This is different comparing to the results for a perfect bilayer spherical cap system (the subject of previous study), where nonlinear image response is dominated by the mismatch of the inner and outer leaflets’ surface areas (as projected to the image plane) at the edge of perfectly spherical structure. The results of theoretical studies, here, demonstrate that Sum Frequency Generation imaging in continuous and deformed bilayer surfaces are helpful to address curvature locally and anticipate mechanical properties of membrane. The articles discuss applicability and practical limitations of the approach. Combination of Atomic Force Microscopy and Sum Frequency Generation imaging under controlled tip-induced deformation provides a good opportunity to probe and test membranes physical properties with rigor of adopted theory.

  12. tRNA structure from a graph and quantum theoretical perspective.

    PubMed

    Galindo, Johan F; Bermúdez, Clara I; Daza, Edgar E

    2006-06-21

    One of the objectives of theoretical biochemistry is to find a suitable representation of molecules allowing us to encode what we know about their structures, interactions and reactivity. Particularly, tRNA structure is involved in some processes like aminoacylation and genetic code translation, and for this reason these molecules represent a biochemical object of the utmost importance requiring characterization. We propose here two fundamental aspects for characterizing and modeling them. The first takes into consideration the connectivity patterns, i.e. the set of linkages between atoms or molecular fragments (a key tool for this purpose is the use of graph theory), and the second one requires the knowledge of some properties related to the interactions taking place within the molecule, at least in an approximate way, and perhaps of its reactivity in certain means. We used quantum mechanics to achieve this goal; specifically, we have used partial charges as a manifestation of the reply to structural changes. These charges were appropriately modified to be used as weighted factors for elements constituting the molecular graph. This new graph-tRNA context allow us to detect some structure-function relationships.

  13. Climatic Change, Conflict and Peace in Transboundary River Basins - A Theoretical Perspective

    NASA Astrophysics Data System (ADS)

    Siegfried, T. U.; Beck, L.; Koubi, V.; Bernauer, T.

    2011-12-01

    Recent research shows that one of the most significant risk for societal development pertains to water availability and that the greatest risks for unrest stemming from economic deprivation and the erosion of livelihoods is found in transboundary river basins in poor and politically unstable parts of the world. While until now, historic linkages between water scarcity and conflict were weak at best, there is growing fear that environmental change will increasingly lead to an entanglement of conflict and resources dynamics in the future. Where resources are not jointly managed in a cooperative way and resources sharing mechanisms not legislated by sound international institutions and were significant impacts from environmental change are expected, these developments give rise to concern. To study environmental change and conflict interlinkages, we develop a formal hydro-climatological model for transboundary freshwater resources and investigate theoretically how climate change translates into potential for conflict and peace, contingent on configurations of power between riparians. The model accounts for how upstream countries exercise power by using water whereas downstream countries use power to obtain water. We show that equilibrium water allocation outcomes are biased towards the more powerful riparian, and that absolute upstream or downstream river basin dominance are limiting cases of our general model. Our model suggests that the basin-wide conflict potential is always more sensitive to changes in relative power between riparian states than to impacts from climatic changes.

  14. Relationships and Betrayal among Young Women: Theoretical Perspectives on Adolescent Dating Abuse

    PubMed Central

    Burton, Candace W.; Halpern-Felsher, Bonnie; Rankin, Sally H.; Rehm, Roberta S.; Humphreys, Janice C.

    2010-01-01

    AIMS Adolescent dating abuse is not specifically described by any current nursing theory, and this paper presents discussion of some existing theories that could inform a nursing theory of adolescent dating abuse. To account for the effects of gender, this discussion is limited to young women. BACKGROUND Adolescent dating abuse is an important and understudied international issue for nursing. Theoretical frameworks can support development of nursing scholarship for such issues. No single theory yet exists within nursing to explain the experiences and health ramifications of dating abuse among young women. DATA SOURCES A summary table of theories is provided. Literature was gathered via database search and bibliographic snowballing from reference lists of relevant articles. Included literature dates from 1982 through 2010. DISCUSSION Theories of relationship formation and function are discussed, including attachment, investment, feminist and gender role conflict theories. Betrayal trauma theory is considered as a mechanism of injury following an abusive dating experience. IMPLICATIONS FOR NURSING Gender, relationship, and adolescence combine in a complex developmental moment for young women. To improve nursing care for those at risk for or in the throes of abusive relationships, it is critical to develop specific nursing approaches to understanding these relationships. CONCLUSION Existing theories related to relationship and traumatic experiences can be combined in the development of a nursing theory of adolescent dating abuse among young women. PMID:21261691

  15. Tip-induced deformation of a phospholipid bilayer: Theoretical perspective of sum frequency generation imaging

    NASA Astrophysics Data System (ADS)

    Volkov, Victor

    2014-10-01

    The paper addresses theory of Sum Frequency Generation imaging of an atomic force microscopy tip-induced deformation of a bilayer phospholipid membrane deposited over a pore: known as a nano-drum system. Image modeling employed nonlinearities of the normal modes specific to hydrocarbon terminal methyls, which are distributed about the deformed surfaces of inner and outer leaflets. The deformed profiles are according to the solutions of shape equation for Canham-Helfrich Hamiltonian accounting properties of four membranes, which differ in elasticity and adhesion. The results indicate that in continuous deformed surfaces, the difference in the curvature of the outer and inner leaflets dominates in the imaged nonlinearity. This is different comparing to the results for a perfect bilayer spherical cap system (the subject of previous study), where nonlinear image response is dominated by the mismatch of the inner and outer leaflets' surface areas (as projected to the image plane) at the edge of perfectly spherical structure. The results of theoretical studies, here, demonstrate that Sum Frequency Generation imaging in continuous and deformed bilayer surfaces are helpful to address curvature locally and anticipate mechanical properties of membrane. The articles discuss applicability and practical limitations of the approach. Combination of Atomic Force Microscopy and Sum Frequency Generation imaging under controlled tip-induced deformation provides a good opportunity to probe and test membranes physical properties with rigor of adopted theory.

  16. Theoretical perspective of FIrpic derivatives: relationship between structures and photophysical properties

    NASA Astrophysics Data System (ADS)

    Li, Jieqiong; Wang, Li; Wang, Xin; Zhang, Jinglai; Cui, Xiaofeng; Li, Youwei; Han, Bingkun

    2017-01-01

    The phosphorescent properties of a series of potential blue-emitting Ir(III) complexes (C^N)2Ir(N^N‧) are studied by means of the density functional theory/time-dependent density functional theory (DFT/TDDFT). Their possibilities to be blue-emitting phosphors are theoretically evaluated by the electroluminescence (EL) performance and phosphorescence quantum yield. The effect of two different substituents attached on the difluorophenyl ring is explored by comparison of the complexes in groups I (1a-4a) and II (1b-4b). Furthermore, to explore the influence of the stronger electron-donating/withdrawing group substituted on the primary ligand, the properties of complexes 1c and 1d are estimated. All the substituents are added on the para-position of the corresponding ring. The comparable radiative rate constant (kr) and nonradiative rate constant (knr) result in the similar quantum yield for complexes in two groups. Besides, the balance of the reorganization energies for complexes 2b-4b is better than others.

  17. Radon hazards, geology, and exposure of cave users: a case study and some theoretical perspectives.

    PubMed

    Gillmore, G K; Sperrin, M; Phillips, P; Denman, A

    2000-07-01

    The concerns over the risks to human health from radon in underground caves are poorly documented, unlike in workplace or domestic environments where exposures are relatively well known. In U.K. caves, radon has been identified as occurring at elevated levels; but with the exception of major show caves, its impact and risk to the many groups who use the caves have thus far received inadequate attention. This paper presents a survey performed in a relatively "low-risk" geographical area of the United Kingdom and quantifies the risk of exposure in this cave environment. Radon levels up to 12,552 Bq m(-3) were measured: Such concentrations are very high but are likely to underestimate the levels in many other parts of the cave system, for reasons associated with cave architecture and meteorology. This study confirms previous workers' conclusions that long-term users of deep caves, as opposed to rock shelters, are at risk. Annual doses to certain groups of cave users have been calculated to be as high as 120 mSv, a very high value. The study also demonstrates that there is variation both within and between caves as a result of subtleties of the bedrock geology, fault patterns, and weathering. This paper sets out a theoretical model.

  18. Cognitive representations of breast cancer, emotional distress and preventive health behaviour: a theoretical perspective.

    PubMed

    Decruyenaere, M; Evers-Kiebooms, G; Welkenhuysen, M; Denayer, L; Claes, E

    2000-01-01

    Individuals at high risk for developing breast and/or ovarian cancer are faced with difficult decisions regarding genetic testing, cancer prevention and/or intensive surveillance. Large interindividual differences exist in the uptake of these health-related services. This paper is aimed at understanding and predicting how people emotionally and behaviourally react to information concerning genetic predisposition to breast/ovarian cancer. For this purpose, the self-regulation model of illness representations is elaborated. This model suggests that health-related behaviour is influenced by a person's cognitive and emotional representation of the health threat. These representations generate coping behaviour aimed at resolving the objective health problems (problem-focussed coping) and at reducing the emotional distress induced by the health threat (emotion-focussed coping). Based on theoretical considerations and empirical studies, four interrelated attributes of the cognitive illness representation of hereditary breast/ovarian cancer are described: causal beliefs concerning the disease, perceived severity, perceived susceptibility to the disease and perceived controllability. The paper also addresses the complex interactions between these cognitive attributes, emotional distress and preventive health behaviour.

  19. The future scalability of pH-based genome sequencers: A theoretical perspective

    NASA Astrophysics Data System (ADS)

    Go, Jonghyun; Alam, Muhammad A.

    2013-10-01

    Sequencing of human genome is an essential prerequisite for personalized medicine and early prognosis of various genetic diseases. The state-of-art, high-throughput genome sequencing technologies provide improved sequencing; however, their reliance on relatively expensive optical detection schemes has prevented wide-spread adoption of the technology in routine care. In contrast, the recently announced pH-based electronic genome sequencers achieve fast sequencing at low cost because of the compatibility with the current microelectronics technology. While the progress in technology development has been rapid, the physics of the sequencing chips and the potential for future scaling (and therefore, cost reduction) remain unexplored. In this article, we develop a theoretical framework and a scaling theory to explain the principle of operation of the pH-based sequencing chips and use the framework to explore various perceived scaling limits of the technology related to signal to noise ratio, well-to-well crosstalk, and sequencing accuracy. We also address several limitations inherent to the key steps of pH-based genome sequencers, which are widely shared by many other sequencing platforms in the market but remained unexplained properly so far.

  20. How much inequality in income is fair? A microeconomic game theoretic perspective

    NASA Astrophysics Data System (ADS)

    Venkatasubramanian, Venkat; Luo, Yu; Sethuraman, Jay

    2015-10-01

    The increasing inequality in income and wealth in recent years, and the associated excessive pay packages of CEOs in the US and elsewhere, is of growing concern among policy makers as well as the common person. However, there seems to be no satisfactory answer, in conventional economic theories and models, to the fundamental questions of what kind of income distribution we ought to see, at least under ideal conditions, in a free market environment, and whether this distribution is fair. We propose a novel microeconomic game theoretic framework that addresses these questions and proves that the lognormal distribution is the fairest inequality of pay in an organization comprising of homogeneous agents, under ideal free market conditions at equilibrium. We also show that for a population of two different classes of agents, the equilibrium distribution is a combination of two different lognormal distributions where one of them, corresponding to the top ˜3-5% of the population, can be misidentified as a Pareto distribution. We compare our predictions with empirical data on global income inequality trends provided by Piketty and others. Our analysis suggests that the Scandinavian countries, and to a lesser extent Switzerland, Netherlands and Australia, have managed to get close to the ideal distribution for the bottom ˜99% of the population, while the US and UK remain less fair at the other extreme. Other European countries such as France and Germany, and Japan and Canada, are in the middle. Our theory also shows the deep and direct connection between potential game theory and statistical mechanics through entropy, which we identify as a measure of fairness in a distribution. This leads us to propose the fair market hypothesis, that the self-organizing dynamics of the ideal free market, i.e., Adam Smith's "invisible hand", not only promotes efficiency but also maximizes fairness under the given constraints.

  1. Migration of scientists and the International Centre for Theoretical Physics -- a Personal and Professional Perspective

    NASA Astrophysics Data System (ADS)

    Sreenivasan, Katepalli R.

    2011-03-01

    Scientists migrate for a variety of reasons: political problems with their governments, lack of professional opportunities in their countries, the lure of better lives, financial security for them and their families, better education for their off-springs, and so forth. Migration usually occurs from poor and oppressed countries--the two categories are not one and the same--to the rich and the open. It has created, over time, a dilemma for the poor countries: in the midst of all their other problems, how to justify spending on higher education and research when that investment often results in the most enterprising of its citizens to leave their countries behind? (When migration has reversed direction occasionally, it is because of certain necessities of the scientists to be back in their countries or for opportunities that some individuals see for wielding greater scientific power.) The ideal of keeping the best scientists in their own countries, still ensuring that they remain scientifically productive and inspiring to the youth, is what provided the motivation for the creation of the International Centre for Theoretical Physics in Trieste, Italy, where I served as Director for some seven years. In this talk, I will present the story behind the formation of the Centre in 1964, explain its rationale, and analyze its evolution over time to accommodate the changing scene in world; I will discuss how some things have remained the same even as more of them have changed over time. Finally, I will remark on the broad needs of developing countries even though such needs are often very specific to a country.

  2. A Cultural Historical Theoretical Perspective of Discourse and Design in the Science Classroom

    ERIC Educational Resources Information Center

    Adams, Megan

    2015-01-01

    Flavio Azevedo, Peggy Martalock and Tugba Keser have initiated an important conversation in science education as they use sociocultural theory to introduce design based scenarios into the science classroom. This response seeks to expand Azevedo, Martalock and Keser's article "The discourse of design-based science classroom activities" by…

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

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  4. Studying Activities That Take Place in Speech Interactions: A Theoretical and Methodological Framework

    ERIC Educational Resources Information Center

    Saint-Dizier de Almeida, Valérie; Colletta, Jean-Marc; Auriac-Slusarczyk, Emmanuelle; Specogna, Antonietta; Simon, Jean-Pascal; Fiema, Gabriela; Luxembourger, Christophe

    2016-01-01

    The paper proposes a theoretical and methodological framework based on a pluralistic, concerted approach to the study of activities that take place in and through speech interactions. The framework has a general scope, applying to any collective activity taking form through language interactions. It contributes to a fuller understanding of the…

  5. Active and successful aging: a European policy perspective.

    PubMed

    Foster, Liam; Walker, Alan

    2015-02-01

    Over the past two decades, "active aging" has emerged in Europe as the foremost policy response to the challenges of population aging. This article examines the concept of active aging and how it differs from that of "successful aging." In particular, it shows how active aging presents a more holistic, life course-oriented approach than successful aging. We provide a critical perspective on active aging too by, first, tracing its emergence in Europe and then showing how, in practice, it has been dominated by a narrow economic or productivist perspective that prioritizes the extension of working life. It has also been gender blind. Nonetheless, it is argued that an active aging approach has the potential to enable countries to respond successfully to the challenges of population aging because of its comprehensive focus and emphasis on societal as well as individual responsibility. Finally, we set out the basic principles that need to be followed if the full potential of active aging is to be achieved.

  6. Active and Successful Aging: A European Policy Perspective

    PubMed Central

    Foster, Liam; Walker, Alan

    2015-01-01

    Over the past two decades, “active aging” has emerged in Europe as the foremost policy response to the challenges of population aging. This article examines the concept of active aging and how it differs from that of “successful aging.” In particular, it shows how active aging presents a more holistic, life course–oriented approach than successful aging. We provide a critical perspective on active aging too by, first, tracing its emergence in Europe and then showing how, in practice, it has been dominated by a narrow economic or productivist perspective that prioritizes the extension of working life. It has also been gender blind. Nonetheless, it is argued that an active aging approach has the potential to enable countries to respond successfully to the challenges of population aging because of its comprehensive focus and emphasis on societal as well as individual responsibility. Finally, we set out the basic principles that need to be followed if the full potential of active aging is to be achieved. PMID:24846882

  7. Metal complexes containing allenylidene and higher cumulenylidene ligands: a theoretical perspective.

    PubMed

    Coletti, Cecilia; Marrone, Alessandro; Re, Nazzareno

    2012-02-21

    Transition metal complexes containing unsaturated carbenes have enjoyed a recent surge in research interest. In addition to showing potential as molecular wires and as components of opto-electronic materials, they provide multifaceted reactive sites for organic synthesis. In this Account, we describe results of recent theoretical studies that delineate the main features of electronic structure and bonding in allenylidenes and higher cumulenylidene complexes, [L(m)M]═C(═C)(n)═CR(1)R(2) (where L represents the ligand, M the metal, and n ≥ 1). Although free cumulenylidene ligands, :C(═C)(n)═CR(1)R(2), are extremely unstable and reactive species, they can be stabilized by coordination to a transition metal. The σ-donation of the electron lone pair on the terminal carbon atom to an empty metal d-orbital, together with the simultaneous π back-donation from filled metal d(π)-orbitals to empty cumulene π* system orbitals, leads to the formation of a strong M═C bond with multiple character. Density functional theory studies on the model systems [(CO)(5)Cr(═C)(n)CH(2)] and [trans-Cl(PH(3))(4)Ru(═C)(n)CH(2)](+) (where n = 1-9) have been useful in interpreting the structural and spectroscopic properties and the reactivity of this class of complexes. Geometry optimizations significantly contributed to the generalization of the sparse structural data available for allenylidene, butatrienylidene, and pentatetraenylidene complexes to higher cumulenylidene complexes (with up to eight carbon atoms in the chain), which show a clear structural trend. In particular, the geometries of all even-chain cumulenes are consistent with an almost purely cumulenic structure, whereas the geometries of odd-chain cumulenes present a significant polyyne-like carbon-carbon bond length alternation. The calculated bond dissociation energies (BDEs) of the cumulenylidene ligand remain almost constant on lengthening the cumulene chain. These BDEs indicate that there is no

  8. Drug-drug interactions related to altered absorption and plasma protein binding: theoretical and regulatory considerations, and an industry perspective.

    PubMed

    Hochman, Jerome; Tang, Cuyue; Prueksaritanont, Thomayant

    2015-03-01

    Drug-drug interactions (DDIs) related to altered drug absorption and plasma protein binding have received much less attention from regulatory agencies relative to DDIs mediated via drug metabolizing enzymes and transporters. In this review, a number of theoretical bases and regulatory framework are presented for these DDI aspects. Also presented is an industry perspective on how to approach these issues in support of drug development. Overall, with the exception of highly permeable and highly soluble (BCS 1) drugs, DDIs related to drug-induced changes in gastrointestinal (GI) physiology can be substantial, thus warranting more attentions. For a better understanding of absorption-associated DDI potential in a clinical setting, mechanistic studies should be conducted based on holistic integration of the pharmaceutical profiles (e.g., pH-dependent solubility) and pharmacological properties (e.g., GI physiology and therapeutic margin) of drug candidates. Although majority of DDI events related to altered plasma protein binding are not expected to be of clinical significance, exceptions exist for a subset of compounds with certain pharmacokinetic and pharmacological properties. Knowledge of the identity of binding proteins and the binding extent in various clinical setting (including disease states) can be valuable in aiding clinical DDI data interpretations, and ensuring safe and effective use of new drugs.

  9. The Library of the Institute of Theoretical Astronomy of the R.A.S. (1924-1994). History, Present State, Perspectives for Future

    NASA Astrophysics Data System (ADS)

    Lapteva, M. V.

    Building up a specialized library collection of the Library of the Institute of Theoretical Astronomy of the Russian Academy of Sciences beginning with foundation of the Library (1924) up to the present time have been considered in their historical perspective. The main acquisition sources, stock figures, various parameters of the collection composi- tion, including information on rare foreign editions are also dealt with. The data on the existing retrieval systems and the perspectives of developing computerized problem directed reference bibliographic complexes are also considered.

  10. Active, capable, and potentially active faults - a paleoseismic perspective

    USGS Publications Warehouse

    Machette, M.N.

    2000-01-01

    Maps of faults (geologically defined source zones) may portray seismic hazards in a wide range of completeness depending on which types of faults are shown. Three fault terms - active, capable, and potential - are used in a variety of ways for different reasons or applications. Nevertheless, to be useful for seismic-hazards analysis, fault maps should encompass a time interval that includes several earthquake cycles. For example, if the common recurrence in an area is 20,000-50,000 years, then maps should include faults that are 50,000-100,000 years old (two to five typical earthquake cycles), thus allowing for temporal variability in slip rate and recurrence intervals. Conversely, in more active areas such as plate boundaries, maps showing faults that are <10,000 years old should include those with at least 2 to as many as 20 paleoearthquakes. For the International Lithosphere Programs' Task Group II-2 Project on Major Active Faults of the World our maps and database will show five age categories and four slip rate categories that allow one to select differing time spans and activity rates for seismic-hazard analysis depending on tectonic regime. The maps are accompanied by a database that describes evidence for Quaternary faulting, geomorphic expression, and paleoseismic parameters (slip rate, recurrence interval and time of most recent surface faulting). These maps and databases provide an inventory of faults that would be defined as active, capable, and potentially active for seismic-hazard assessments.

  11. Presenting Theoretical Ideas Prior to Inquiry Activities Fosters Theory-Level Knowledge

    ERIC Educational Resources Information Center

    Wecker, Christof; Rachel, Alexander; Heran-Dörr, Eva; Waltner, Christine; Wiesner, Hartmut; Fischer, Frank

    2013-01-01

    In the course of inquiry activities similar to those of real scientists, learners are supposed to develop knowledge both on the level of observable phenomena and on the level of explanatory theories. However, some theories involve theoretical entities (e.g., "Weiss domains") that cannot be observed directly and therefore may be hard to…

  12. Changes in visual perspective influence brain activity patterns during cognitive perspective-taking of other people's pain.

    PubMed

    Vistoli, Damien; Achim, Amélie M; Lavoie, Marie-Audrey; Jackson, Philip L

    2016-05-01

    Empathy refers to our capacity to share and understand the emotional states of others. It relies on two main processes according to existing models: an effortless affective sharing process based on neural resonance and a more effortful cognitive perspective-taking process enabling the ability to imagine and understand how others feel in specific situations. Until now, studies have focused on factors influencing the affective sharing process but little is known about those influencing the cognitive perspective-taking process and the related brain activations during vicarious pain. In the present fMRI study, we used the well-known physical pain observation task to examine whether the visual perspective can influence, in a bottom-up way, the brain regions involved in taking others' cognitive perspective to attribute their level of pain. We used a pseudo-dynamic version of this classic task which features hands in painful or neutral daily life situations while orthogonally manipulating: (1) the visual perspective with which hands were presented (first-person versus third-person conditions) and (2) the explicit instructions to imagine oneself or an unknown person in those situations (Self versus Other conditions). The cognitive perspective-taking process was investigated by comparing Other and Self conditions. When examined across both visual perspectives, this comparison showed no supra-threshold activation. Instead, the Other versus Self comparison led to a specific recruitment of the bilateral temporo-parietal junction when hands were presented according to a first-person (but not third-person) visual perspective. The present findings identify the visual perspective as a factor that modulates the neural activations related to cognitive perspective-taking during vicarious pain and show that this complex cognitive process can be influenced by perceptual stages of information processing.

  13. Exergames: Theoretical perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper is based on an invited presentation as part of the Exergame Preconference Symposium held in Houston, TX May 19-20, 2014 that was hosted by Tom Baranowski, PhD, and the USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine. Its purpose is to provide insight into the way...

  14. Simple control-theoretic models of human steering activity in visually guided vehicle control

    NASA Technical Reports Server (NTRS)

    Hess, Ronald A.

    1991-01-01

    A simple control theoretic model of human steering or control activity in the lateral-directional control of vehicles such as automobiles and rotorcraft is discussed. The term 'control theoretic' is used to emphasize the fact that the model is derived from a consideration of well-known control system design principles as opposed to psychological theories regarding egomotion, etc. The model is employed to emphasize the 'closed-loop' nature of tasks involving the visually guided control of vehicles upon, or in close proximity to, the earth and to hypothesize how changes in vehicle dynamics can significantly alter the nature of the visual cues which a human might use in such tasks.

  15. Perspectives on Physical Activity and Exercise Among Appalachian Youth

    PubMed Central

    Swanson, Mark; Schoenberg, Nancy E.; Erwin, Heather; Davis, Rian E.

    2015-01-01

    Background Most children in the United States receive far less physical activity (PA) than is optimal. In rural, under resourced areas of Appalachian Kentucky, physical inactivity rates are significantly higher than national levels. We sought to understand children’s perceptions of PA, with the goal of developing culturally appropriate programming to increase PA. Methods During 11 focus groups, we explored perspectives on PA among 63 Appalachian children, ages 8–17. Sessions were tape recorded, transcribed, content analyzed, and subjected to verification procedures. Results Several perspectives on PA emerged among these rural Appalachian youth, including the clear distinction between PA (viewed as positive) and exercise (viewed as negative) and an emphasis on time and resource factors as barriers to adequate PA. Additional PA determinants expressed in the focus groups are similar to those of other populations. We include children’s recommendations for appealing PA programs. Conclusions Appalachian and other rural residents contend with the loss of rural health advantages (due to declines in farming/other occupational and avocational transitions). At the same time, Appalachian residents have not benefitted from urban PA facilitators (sidewalks, recreational facilities, clubs and organized leisure activities). Addressing low PA levels requires extensive community input and creative programming. PMID:22397810

  16. New Perspectives on Spontaneous Brain Activity: Dynamic Networks and Energy Matter

    PubMed Central

    Tozzi, Arturo; Zare, Marzieh; Benasich, April A.

    2016-01-01

    Spontaneous brain activity has received increasing attention as demonstrated by the exponential rise in the number of published article on this topic over the last 30 years. Such “intrinsic” brain activity, generated in the absence of an explicit task, is frequently associated with resting-state or default-mode networks (DMN)s. The focus on characterizing spontaneous brain activity promises to shed new light on questions concerning the structural and functional architecture of the brain and how they are related to “mind”. However, many critical questions have yet to be addressed. In this review, we focus on a scarcely explored area, specifically the energetic requirements and constraints of spontaneous activity, taking into account both thermodynamical and informational perspectives. We argue that the “classical” definitions of spontaneous activity do not take into account an important feature, that is, the critical thermodynamic energetic differences between spontaneous and evoked brain activity. Spontaneous brain activity is associated with slower oscillations compared with evoked, task-related activity, hence it exhibits lower levels of enthalpy and “free-energy” (i.e., the energy that can be converted to do work), thus supporting noteworthy thermodynamic energetic differences between spontaneous and evoked brain activity. Increased spike frequency during evoked activity has a significant metabolic cost, consequently, brain functions traditionally associated with spontaneous activity, such as mind wandering, require less energy that other nervous activities. We also review recent empirical observations in neuroscience, in order to capture how spontaneous brain dynamics and mental function can be embedded in a non-linear dynamical framework, which considers nervous activity in terms of phase spaces, particle trajectories, random walks, attractors and/or paths at the edge of the chaos. This takes us from the thermodynamic free-energy, to the realm

  17. Perspectives from space: NASA classroom information and activities

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This booklet contains the information and classroom activities included on the backs of the eight poster series, 'Perspectives From Space'. The first series, Earth, An Integrated System, contains information on global ecology, remote sensing from space, data products, earth modeling, and international environmental treaties. The second series, Patterns Among Planets, contains information on the solar system, planetary processes, impacts and atmospheres, and a classroom activity on Jupiter's satellite system. The third series, Our Place In The Cosmos, contains information on the scale of the universe, origins of the universe, mission to the universe, and three classroom activities. The fourth series, Our Sun, The Nearest Star, contains information on the Sun. The fifth series, Oasis Of Life, contains information on the development of life, chemical and biological evolution on Earth and the search for other life in the universe. The sixth series, The Influence Of Gravity, contains information on Newton's Law of Gravity, space and microgravity, microgravity environment, and classroom activities on gravity. The seventh series, The Spirit Of Exploration, contains information on space exploration, the Apollo Program, future exploration activities, and two classroom activities. The eighth series, Global Cooperation, contains information on rocketry, the space race, and multi-nation exploration projects.

  18. Investigating theoretical explanations for behaviour change: the case study of ProActive.

    PubMed

    Michie, Susan; Hardeman, Wendy; Fanshawe, Tom; Prevost, A Toby; Taylor, Lyndsay; Kinmonth, Ann Louise

    2008-01-01

    Developing more effective behavioural interventions requires an understanding of the mechanisms of behaviour change, and methods to rigorously test their theoretical basis. The delivery and theoretical basis of an intervention protocol were assessed in ProActive, a UK trial of an intervention to increase the physical activity of those at risk of Type 2 diabetes (N = 365). In 108 intervention sessions, behaviours of facilitators were mapped to four theories that informed intervention development and behaviours of participants were mapped to 17 theoretical components of these four theories. The theory base of the intervention specified by the protocol was different than that delivered by facilitators, and that received by participants. Of the intervention techniques delivered, 25% were associated with theory of planned behaviour (TPB), 42% with self-regulation theory (SRT), 24% with operant learning theory (OLT) and 9% with relapse prevention theory (RPT). The theoretical classification of participant talk showed a different pattern, with twice the proportion associated with OLT (48%), 21% associated with TPB, 31% with SRT and no talk associated with RPT. This study demonstrates one approach to assessing the extent to which the theories used to guide intervention development account for any changes observed.

  19. Advocacy for active transport: advocate and city council perspectives

    PubMed Central

    2010-01-01

    Background Effective advocacy is an important part of efforts to increase population participation in physical activity. Research about effective health advocacy is scarce, however, the health sector can learn from the experiences and knowledge of community advocates and those who are on the receiving end of this advocacy. The aim of this study is to explore advocacy for active transport from the perspectives of community advocates and representatives from City councils. Methods Cycling and walking advocates were identified from the local contact list of Cycling Advocates Network and Living Streets Aotearoa. Semi-structured telephone interviews were conducted with cycle and walking advocates from throughout New Zealand. Advocates also nominated a suitable council officer at their local City council to be interviewed. Interviews were recorded and transcribed and categories of responses for each of the questions created. Results Several processes were used by advocates to engage with council staff, including formal council submissions, meetings, stakeholder forums and partnership in running community events promoting active transport. Several other agencies were identified as being influential for active transport, some as potential coalition partners and others as potential adversaries. Barriers to improving conditions for active transport included a lack of funding, a lack of will-power among either council staff or councillors, limited council staff capacity (time or training) and a culture of providing infrastructure for motor vehicles instead of people. Several suggestions were made about how the health sector could contribute to advocacy efforts, including encouraging political commitment, engaging the media, communicating the potential health benefits of active transport to the general public and being role models in terms of personal travel mode choice and having workplaces that support participation in active transport. Conclusions There is potential for the

  20. Advances in the theoretical understanding of photon upconversion in rare-earth activated nanophosphors.

    PubMed

    Liu, Guokui

    2015-03-21

    Photon upconversion in rare earth activated phosphors involves multiple mechanisms of electronic transitions. Stepwise optical excitation, energy transfer, and various nonlinear and collective light-matter interaction processes act together to convert low-energy photons into short-wavelength light emission. Upconversion luminescence from nanomaterials exhibits additional size and surface dependencies. A fundamental understanding of the overall performance of an upconversion system requires basic theories on the spectroscopic properties of solids containing rare earth ions. This review article surveys the recent progress in the theoretical interpretations of the spectroscopic characteristics and luminescence dynamics of photon upconversion in rare earth activated phosphors. The primary aspects of upconversion processes, including energy level splitting, transition probability, line broadening, non-radiative relaxation and energy transfer, are covered with an emphasis on interpreting experimental observations. Theoretical models and methods for analyzing nano-phenomena in upconversion are introduced with detailed discussions on recently reported experimental results.

  1. Hospital chief executive officer perspective on professional development activities.

    PubMed

    Khaliq, Amir A; Walston, Stephen L

    2010-01-01

    A study was undertaken to develop understanding of hospital chief executive officers' (CEOs') perspectives concerning importance and impact of professional development activities in US hospitals. It was also intended to reveal CEO preferences for various modalities of professional development including membership in professional societies, attainment of credentials, and coaching by mentors. A mail survey of 582 hospital CEOs made use of a pilot-tested questionnaire with 30 close ended multipart questions. Results showed that most CEOs assigned a high level of importance to professional development and favored conferences, seminars, and networking opportunities, but low priority assigned to online activities such as webinars. They reported lending support to senior managers for participation in these activities by providing financial resources and by allowing time off to engage in these activities. The respondents indicated that the importance of various modalities of professional development has either increased or remained high over the recent 5 years. Conclusions suggest that verifiable quantitative data are needed for understanding of the frequency of participation and resource commitment of health care organizations toward the professional development of CEOs and senior managers. The results of this perceptual study reveal a high level of importance accorded to various forms of professional development activities by the participating CEOs.

  2. Contradictions between the Virtual and Physical High School Classroom: A Third-Generation Activity Theory Perspective

    ERIC Educational Resources Information Center

    Murphy, Elizabeth; Manzanares, Maria A. Rodriguez

    2008-01-01

    This paper uses a third-generation Activity Theory perspective to gain insight into the contradictions between the activity systems of the physical and virtual high school classroom from the perspective of teachers who had transitioned from one system to the other. Data collection relied on semi-structured interviews conducted with e-teachers as…

  3. Der soziologische Neo-Institutionalismus. Eine organisationstheoretische Analyse -- und Forschungsperspektive auf Schulische Organisationen (Sociological Neo-Institutionalism. An Organization--Theoretical Perspective Applied to the Analysis of and Research on School Organization).

    ERIC Educational Resources Information Center

    Schaefers, Christine

    2002-01-01

    Points out the potential in a neo-institutional perspective as applied to school organization. Sketches the theoretical foundations and current developments of sociological neo-institutionalism. Discusses the German school system and plans for school reform. Shows that from a neo-institutional perspective, school sector offers a variety of fields…

  4. [Swimming, physical activity and health: a historical perspective].

    PubMed

    Conti, A A

    2015-01-01

    Swimming, which is the coordinated and harmonic movement of the human body inside a liquid medium by means of the combined action of the superior and inferior limbs, is a physical activity which is diffused throughout the whole world and it is practiced by healthy and non-healthy subjects. Swimming is one of the physical activities with less contraindications and, with limited exceptions, can be suggested to individuals of both sexes and of every age range, including the most advanced. Swimming requires energy both for the floating process and for the anterograde progression, with a different and variable osteo-arthro-muscular involvement according to the different styles. The energetic requirement is about four times that for running, with an overall efficiency inferior to 10%; the energetic cost of swimming in the female subject is approximately two thirds of that in the male subject. The moderate aerobic training typical of swimming is useful for diabetic and hypertensive individuals, for people with painful conditions of rachis, as also for obese and orthopaedic patients. Motor activity inside the water reduces the risk of muscular-tendinous lesions and, without loading the joints in excess, requires the harmonic activation of the whole human musculature. Swimming is an activity requiring multiple abilities, ranging from a sense of equilibrium to that of rhythm, from reaction speed to velocity, from joint mobility to resistance. The structured interest for swimming in the perspective of human health from the beginning of civilization, as described in this contribution, underlines the relevance attributed to this activity in the course of human history.

  5. Experimental and theoretical investigations on the antioxidant activity of isoorientin from Crotalaria globosa

    NASA Astrophysics Data System (ADS)

    Deepha, V.; Praveena, R.; Sivakumar, Raman; Sadasivam, K.

    2014-03-01

    The increasing interests in naturally occurring flavonoids are well known for their bioactivity as antioxidants. The present investigations with combined experimental and theoretical methods are employed to determine the radical scavenging activity and phytochemicals present in Crotalaria globosa, a novel plant source. Preliminary quantification of ethanolic extract of leaves shows high phenolic and flavonoid content than root extract; also it is validated through DPPHrad assay. Further analysis is carried out with successive extracts of leaves of varying polarity of solvents. In DPPHrad and FRAP assays, ethyl acetate fraction (EtOAc) exhibit higher scavenging activity followed by ethanol fraction (EtOH) whereas in NOS assay ethanol fraction is slightly predominant over the EtOAc fraction. The LC-MS analysis provides tentative information about the presence of flavonoid C-glycoside in EtOAc fraction (yellow solid). Presence of flavonoid isorientin has been confirmed through isolation (PTLC) and detected by spectroscopy methods (UV-visible and 1H NMR). Utilizing B3LYP/6-311G (d,p) level of theory the structure and reactivity of flavonoid isoorientin theoretically have been explored. The analysis of the theoretical Bond dissociation energy values, for all Osbnd H sites of isoorientin reveals that minimum energy is required to dissociate H-atom from B-ring than A and C-rings. In order to validate the antioxidant characteristics of isoorientin the relevant molecular descriptors IP, HOMO-LUMO, Mulliken spin density analysis and molecular electrostatic potential surfaces have been computed and interpreted. From experimental and theoretical results, it is proved that isoorientin can act as potent antiradical scavenger in oxidative system.

  6. Iso standardization of theoretical activity evaluation method for low and intermediate level activated waste generated at nuclear power plants

    SciTech Connect

    Makoto Kashiwagi; Garamszeghy, Mike; Lantes, Bertrand; Bonne, Sebastien; Pillette-Cousin, Lucien; Leganes, Jose Luis; Volmert, Ben; James, David W.

    2013-07-01

    Disposal of low-and intermediate-level activated waste generated at nuclear power plants is being planned or carried out in many countries. The radioactivity concentrations and/or total quantities of long-lived, difficult-to-measure nuclides (DTM nuclides), such as C-14, Ni-63, Nb-94, α emitting nuclides etc., are often restricted by the safety case for a final repository as determined by each country's safety regulations, and these concentrations or amounts are required to be known and declared. With respect to waste contaminated by contact with process water, the Scaling Factor method (SF method), which is empirically based on sampling and analysis data, has been applied as an important method for determining concentrations of DTM nuclides. This method was standardized by the International Organization for Standardization (ISO) and published in 2007 as ISO21238 'Scaling factor method to determine the radioactivity of low and intermediate-level radioactive waste packages generated at nuclear power plants' [1]. However, for activated metal waste with comparatively high concentrations of radioactivity, such as may be found in reactor control rods and internal structures, direct sampling and radiochemical analysis methods to evaluate the DTM nuclides are limited by access to the material and potentially high personnel radiation exposure. In this case, theoretical calculation methods in combination with empirical methods based on remote radiation surveys need to be used to best advantage for determining the disposal inventory of DTM nuclides while minimizing exposure to radiation workers. Pursuant to this objective a standard for the theoretical evaluation of the radioactivity concentration of DTM nuclides in activated waste, is in process through ISO TC85/SC5 (ISO Technical Committee 85: Nuclear energy, nuclear technologies, and radiological protection; Subcommittee 5: Nuclear fuel cycle). The project team for this ISO standard was formed in 2011 and is composed of

  7. A question of balance: Explaining differences between parental and grandparental perspectives on preschoolers' feeding and physical activity

    PubMed Central

    Eli, Karin; Howell, Kyndal; Fisher, Philip A.; Nowicka, Paulina

    2017-01-01

    Rationale Although one quarter of US and UK families rely on grandparents as the main providers of informal childcare, grandparental perspectives on the feeding and physical activity of young children remain understudied. Objective The study's aim was to elucidate parents' and grandparents' perspectives on young children's feeding and physical activity, and identify how they negotiate potential differences between these perspectives. Methods We interviewed 22 parents and 27 grandparents from 16 families of children aged 3–5 years in the Pacific Northwest, US. Using familial homeostasis as a novel theoretical framework, the interviews were analyzed to assess differences between parental and grandparental perspectives on feeding and physical activity. Results The analysis yielded six thematic categories: (1) disagreements about feeding stem from parents' and grandparents' differing definitions of healthy feeding; (2) differences between parents' and grandparents' feeding practices reflect differences in perceived caretaking roles; (3) parents and grandparents negotiate differences in feeding practices through grandparental compliance and parental compromise; (4) differences in preschoolers' physical activity are influenced by parents' and grandparents' own access to and engagement in physical activity; (5) parents and grandparents express few disagreements about preschoolers' screen-time; (6) parents and grandparents rarely discuss preschoolers' physical activity. The findings suggest that parental and grandparental decision-making about feeding and exercise is informed by ideas of what constitutes familial balance and a balanced lifestyle for a preschool aged child, rather than by the child's weight status. Conclusions Parents and grandparents appear to engage in practices designed to preserve familial homeostasis, which may provide a compelling explanation for the persistent difficulties in implementing family-based childhood obesity interventions. PMID:26943011

  8. Theoretical perspective on the electronic, magnetic and optical properties of Zn-doped monolayer SnS2

    NASA Astrophysics Data System (ADS)

    Sun, Lili; Zhou, Wei; Liu, Yanyu; Yu, Dandan; Liang, Yinghua; Wu, Ping

    2016-12-01

    The electronic, magnetic and optical properties of Zn-doped monolayer SnS2 have been theoretically investigated with the density functional theory. Numerical results reveal that monolayer SnS2 can be easily synthesized by cleaving its bulk crystal. Besides, the Zn doping in monolayer SnS2 is energetically favored under the S-rich with respect to the Sn-rich condition. The doped system exhibits the magnetic ground states due to the formation of defect states above the Fermi level, which are introduced by the hybridization between S-3p states and a small amount of Sn-4d states. The room temperature ferromagnetism can also be realized in Zn-doped monolayer SnS2. The injection of Zn can enhance the absorption efficiency of solar spectrum, especially in the near-infrared light region. Moreover, the Zn doping can enhance the photocatalytic activity for both the oxygen and hydrogen evolution reactions in the monolayer SnS2.

  9. Theoretical investigation of the activity of cobalt oxides for the electrochemical oxidation of water.

    PubMed

    Bajdich, Michal; García-Mota, Mónica; Vojvodic, Aleksandra; Nørskov, Jens K; Bell, Alexis T

    2013-09-11

    The presence of layered cobalt oxides has been identified experimentally in Co-based anodes under oxygen-evolving conditions. In this work, we report the results of theoretical investigations of the relative stability of layered and spinel bulk phases of Co oxides, as well as the stability of selected surfaces as a function of applied potential and pH. We then study the oxygen evolution reaction (OER) on these surfaces and obtain activity trends at experimentally relevant electro-chemical conditions. Our calculated volume Pourbaix diagram shows that β-CoOOH is the active phase where the OER occurs in alkaline media. We calculate relative surface stabilities and adsorbate coverages of the most stable low-index surfaces of β-CoOOH: (0001), (0112), and (1014). We find that at low applied potentials, the (1014) surface is the most stable, while the (0112) surface is the more stable at higher potentials. Next, we compare the theoretical overpotentials for all three surfaces and find that the (1014) surface is the most active one as characterized by an overpotential of η = 0.48 V. The high activity of the (1014) surface can be attributed to the observation that the resting state of Co in the active site is Co(3+) during the OER, whereas Co is in the Co(4+) state in the less active surfaces. Lastly, we demonstrate that the overpotential of the (1014) surface can be lowered further by surface substitution of Co by Ni. This finding could explain the experimentally observed enhancement in the OER activity of Ni(y)Co(1-y)O(x) thin films with increasing Ni content. All energetics in this work were obtained from density functional theory using the Hubbard-U correction.

  10. Reality-Theoretical Models-Mathematics: A Ternary Perspective on Physics Lessons in Upper-Secondary School

    ERIC Educational Resources Information Center

    Hansson, Lena; Hansson, Örjan; Juter, Kristina; Redfors, Andreas

    2015-01-01

    This article discusses the role of mathematics during physics lessons in upper-secondary school. Mathematics is an inherent part of theoretical models in physics and makes powerful predictions of natural phenomena possible. Ability to use both theoretical models and mathematics is central in physics. This paper takes as a starting point that the…

  11. Active perspective taking induces flexible use of self-knowledge during social inference.

    PubMed

    Todd, Andrew R; Simpson, Austin J; Tamir, Diana I

    2016-12-01

    Social life hinges on the ability to infer others' mental states. By default, people often recruit self-knowledge during social inference, particularly for others who are similar to oneself. How do people's active perspective-taking efforts-deliberately imagining another's perspective-affect self-knowledge use? In 2 experiments, we test the flexible self-application hypothesis: that the application of self-knowledge to a perspective-taking target differs based on that person's similarity to oneself. We found consistent evidence that, when making inferences about dissimilar others, perspective taking increased the projection of one's own traits and preferences to those targets, relative to a control condition. When making inferences about similar others, however, perspective taking decreased projection. These findings suggest that self-target similarity critically shapes the inferential processes triggered by active perspective-taking efforts. (PsycINFO Database Record

  12. Textbook Questions in Context-Based and Traditional Chemistry Curricula Analysed from a Content Perspective and a Learning Activities Perspective

    NASA Astrophysics Data System (ADS)

    Overman, Michelle; Vermunt, Jan D.; Meijer, Paulien C.; Bulte, Astrid M. W.; Brekelmans, Mieke

    2013-11-01

    In this study, questions in context-based and traditional chemistry textbooks were analysed from two perspectives that are at the heart of chemistry curricula reforms: a content perspective and a learning activities perspective. To analyse these textbook questions, we developed an instrument for each perspective. In total, 971 textbook questions were analysed. Textbook questions in context-based and traditional curricula appeared to differ significantly in their orientation on content and in the activation to engage students in certain learning activities. Although traditional curricula included more questions that stress traditional chemistry content and included more reproductive chemistry questions than context-based curricula, they were not always as traditional as we had expected. Context-based chemistry curricula focused more on chemistry content relating to societal/technological issues and chemistry theory development and also more questions were included that activate students to regulate their own learning. However, context-based chemistry curricula still included a considerable amount of traditional chemistry content and did not focus as much on higher order learning as we had expected. The developed instruments might be helpful in chemistry curricula design to gain insights into the content which is stressed and how students are activated by textbook questions to engage in learning.

  13. "Please Don't Just Hang a Feather on a Program or Put a Medicine Wheel on Your Logo and Think 'Oh Well, This Will Work'": Theoretical Perspectives of American Indian and Alaska Native Substance Abuse Prevention Programs.

    PubMed

    Walsh-Buhi, Margaret L

    Many current theories guiding substance abuse prevention (SAP) programs stem from Western ideologies, leading to a scarcity of research on theories from, and a disconnect with, Indigenous perspectives. This qualitative research study explored perceptions of theory by SAP researchers (N = 22) working with American Indian and Alaska Native communities. In-depth interviews identified components of Indigenous theoretical perspectives, including cultural elements such as balance, social cohesion, and belonging as being particularly significant and currently absent from many SAP programs. Recommendations for conducting metatheory studies and operationalization of Indigenous perspectives into guiding theoretical underpinnings for future SAP programming are provided.

  14. Surface activity of Janus particles adsorbed at fluid-fluid interfaces: Theoretical and experimental aspects.

    PubMed

    Fernandez-Rodriguez, Miguel Angel; Rodriguez-Valverde, Miguel Angel; Cabrerizo-Vilchez, Miguel Angel; Hidalgo-Alvarez, Roque

    2016-07-01

    Since de Gennes coined in 1992 the term Janus particle (JP), there has been a continued effort to develop this field. The purpose of this review is to present the most relevant theoretical and experimental results obtained so far on the surface activity of amphiphilic JPs at fluid interfaces. The surface activity of JPs at fluid-fluid interfaces can be experimentally determined using two different methods: the classical Langmuir balance or the pendant drop tensiometry. The second method requires much less amount of sample than the first one, but it has also some experimental limitations. In all cases collected here the JPs exhibited a higher surface or interfacial activity than the corresponding homogeneous particles. This reveals the significant advantage of JPs for the stabilization of emulsions and foams.

  15. Validation of theoretical framework explaining active solute uptake in dynamically loaded porous media.

    PubMed

    Albro, Michael B; Li, Roland; Banerjee, Rajan E; Hung, Clark T; Ateshian, Gerard A

    2010-08-26

    Solute transport in biological tissues is a fundamental process necessary for cell metabolism. In connective soft tissues, such as articular cartilage, cells are embedded within a dense extracellular matrix that hinders the transport of solutes. However, according to a recent theoretical study (Mauck et al., 2003, J. Biomech. Eng. 125, 602-614), the convective motion of a dynamically loaded porous solid matrix can also impart momentum to solutes, pumping them into the tissue and giving rise to concentrations which exceed those achived under passive diffusion alone. In this study, the theoretical predictions of this model are verified against experimental measurements. The mechanical and transport properties of an agarose-dextran model system were characterized from independent measurements and substituted into the theory to predict solute uptake or desorption under dynamic mechanical loading for various agarose concentrations and dextran molecular weights, as well as different boundary and initial conditions. In every tested case, agreement was observed between experiments and theoretical predictions as assessed by coefficients of determination ranging from R(2)=0.61 to 0.95. These results provide strong support for the hypothesis that dynamic loading of a deformable porous tissue can produce active transport of solutes via a pumping mechanisms mediated by momentum exchange between the solute and solid matrix.

  16. Theoretical and experimental study of aparisthman: A natural product with anti-ulcer activity

    NASA Astrophysics Data System (ADS)

    Brasil, D. S. B.; Moreira, R. Y. O.; Müller, A. H.; Alves, C. N.

    Aparisthman is a furan diterpenoid with a clerodane skeleton isolated from Aparisthmium cordatum (Juss.) Bail. (Euphorbiaceae). This natural product presents significant anti-ulcer activity to the level of cimetidine (Tagamet®), a compound used for the treatment of ulcers provoked by stress. The structure of X-ray diffraction of the aparisthman was compared with theoretical calculations and the results showed that the theory is in accordance with the experimental data. The infrared (IR) and nuclear magnetic resonance (NMR) spectra also were obtained and compared with theoretical calculations. The B3LYP theory level, with the 6-31G(d,p) basis set, leads the value to the IR absorption close to the value experimentally observed. NMR theoretical obtained with HF/6-311+G(2d,p) shows little deviation of experimental results. Calculations of molecular electrostatic potential and stabilization energies suggest that the protonation of aparisthman will be able to occur on carbonyl oxygen atom (O4).

  17. Synthesis, characterization, investigation of biological activity and theoretical studies of hydrazone compounds containing choloroacetyl group

    NASA Astrophysics Data System (ADS)

    Cukurovali, Alaaddin; Yilmaz, Engin

    2014-10-01

    In this study, three new hydrazide-hydrazone derivative compounds which contain choloroacetyl group have been synthesized and characterized. In the characterization, spectral techniques such as IR, 1H NMR, 13C NMR and UV-Vis spectroscopy techniques were used. Antibacterial effects of the synthesized compounds were investigated against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. In the theoretical calculations Gaussian 09 software was used with the DFT/6-311+(d,p) basis set. Experimental X-ray analysis of compounds has not been studied. Theoretical bond lengths of synthesized compounds were compared with experimental bond lengths of a similar compound. Theoretical and experimental bond lengths are in good agreement with R2: 0.896, 0.899 and 0.900 for compounds 1, 2, and 3, respectively. For antibacterial activity, the most effective one was found to be N‧-(4-bromobenzylidene)-2-chloro-N-(4-(3-methyl-3-phenylcyclobutyl)-thiazol-2-yl) acetohydrazide against P.aeroginaosa ATTC 27853, among the studied compounds.

  18. Validation of theoretical framework explaining active solute uptake in dynamically loaded porous media

    PubMed Central

    Albro, Michael B.; Li, Roland; Banerjee, Rajan E.; Hung, Clark T.; Ateshian, Gerard A.

    2010-01-01

    Solute transport in biological tissues is a fundamental process necessary for cell metabolism. In connective soft tissues, such as articular cartilage, cells are embedded within a dense extracellular matrix that hinders the transport of solutes. However, according to a recent theoretical study (Mauck et al., 2003, J. Biomech. Eng. 125, 602–614), the convective motion of a dynamically loaded porous solid matrix can also impart momentum to solutes, pumping them into the tissue and giving rise to concentrations which exceed those achived under passive diffusion alone. In this study, the theoretical predictions of this model are verified against experimental measurements. The mechanical and transport properties of an agarose–dextran model system were characterized from independent measurements and substituted into the theory to predict solute uptake or desorption under dynamic mechanical loading for various agarose concentrations and dextran molecular weights, as well as different boundary and initial conditions. In every tested case, agreement was observed between experiments and theoretical predictions as assessed by coefficients of determination ranging from R2=0.61 to 0.95. These results provide strong support for the hypothesis that dynamic loading of a deformable porous tissue can produce active transport of solutes via a pumping mechanisms mediated by momentum exchange between the solute and solid matrix. PMID:20553797

  19. Where is the Theoretical Basis for Understanding and Measuring the Environment for Physical Activity?

    PubMed

    Nelson, N M; Wright, A; Lowry, R G; Mutrie, N

    2008-12-02

    Researchers are beginning to explore environmental correlates to further the field of physical activity research. Before interventions and experimental investigations can be undertaken, it is necessary to identify specific environmental features that are consistent correlates of physical activity. There has been a plethora of research measuring such cross-sectional associations since this field came to the fore in 2003. This paper posits that it is time for researchers to evaluate the state of knowledge, and suggests that future developments in this field focus on the theoretical bases for (i) measurement of the environment and (ii) understanding the links between perceptions of the environment and behaviour through psychological theories of cognition. Key theories considered include social ecology and the theory of planned behaviour. It is suggested that with a continued absence of a common conceptual framework, vocabulary and measurement tools the majority of studies may remain at a correlates stage. In highlighting issues with current methodologies, this commentary encourages more grounded theoretical approaches to the study of the environment and physical activity.

  20. Experimental and theoretical approach of nanocrystalline TiO2 with antifungal activity

    NASA Astrophysics Data System (ADS)

    Longo, Valeria M.; Picon, Francini C.; Zamperini, Camila; Albuquerque, Anderson R.; Sambrano, Julio R.; Vergani, Carlos E.; Machado, Ana L.; Andrés, Juan; Hernandes, Antônio C.; Varela, José A.; Longo, Elson

    2013-07-01

    Using a solvothermal method for this research we synthesized nanocrystalline titanium dioxide (nc-TiO2) anatase particles with a mean diameter of 5.4 nm and evaluated their potential antifungal effect against planktonic cells of Candida albicans without UV radiation. To complement experimental data, we analyzed structural and electronic properties of both the bulk and the (1 0 1) surface of anatase by first-principles calculations. Based on experimental and theoretical results, a reactive O2H and OH species formation mechanism was proposed to explain the key factor which facilitates the antifungal activity.

  1. C/1995 O1 Hale-Bopp: Short and Long Distance activity from a Theoretical Model

    NASA Astrophysics Data System (ADS)

    Capria, Maria Teresa; Coradini, Angioletta; de Sanctis, Maria Cristina

    2002-06-01

    A theoretical model of the nucleus thermal evolutionand differentiation is used to simulatethe evolution along the orbit of the gasand dust emissions of comet Hale-Bopp. The model was already applied to this comet (Capria et al., 2000b): At that time only the results of the observations obtained shortly after the perihelion were available. Now much more data have been published and we present more refined and complete results about the production rates of gasand dust along the orbit and the internal stratigraphy. The results of our model on long distance activity and its explanation are also presented.

  2. Mundane science use in a practice theoretical perspective: Different understandings of the relations between citizen-consumers and public communication initiatives build on scientific claims.

    PubMed

    Halkier, Bente

    2015-08-13

    Public communication initiatives play a part in placing complicated scientific claims in citizen-consumers' everyday contexts. Lay reactions to scientific claims framed in public communication, and attempts to engage citizens, have been important subjects of discussion in the literatures of public understanding and public engagement with science. Many of the public communication initiatives, however, address lay people as consumers rather than citizens. This creates specific challenges for understanding public engagement with science and scientific citizenship. The article compares five different understandings of the relations between citizen-consumers and public issue communication involving science, where the first four types are widely represented in the Public Understanding of Science discussions. The fifth understanding is a practice theoretical perspective. The article suggests how the public understanding of and engagement in science literature can benefit from including a practice theoretical approach to research about mundane science use and public engagement.

  3. Development Mechanism of an Integrated Model for Training of a Specialist and Conceptual-Theoretical Activity of a Teacher

    ERIC Educational Resources Information Center

    Marasulov, Akhmat; Saipov, Amangeldi; ?rymbayeva, Kulimkhan; Zhiyentayeva, Begaim; Demeuov, Akhan; Konakbaeva, Ulzhamal; Bekbolatova, Akbota

    2016-01-01

    The aim of the study is to examine the methodological-theoretical construction bases for development mechanism of an integrated model for a specialist's training and teacher's conceptual-theoretical activity. Using the methods of generalization of teaching experience, pedagogical modeling and forecasting, the authors determine the urgent problems…

  4. Building a Theoretical Model of Metacognitive Processes in Complex Modeling Activities: A Window into the Development of Students' Metacognitive Abilities

    ERIC Educational Resources Information Center

    Kim, Young Rae

    2013-01-01

    A theoretical model of metacognition in complex modeling activities has been developed based on existing frameworks, by synthesizing the re-conceptualization of metacognition at multiple levels by looking at the three sources that trigger metacognition. Using the theoretical model as a framework, this study was designed to explore how students'…

  5. Infusing a Global Perspective into the Study of Agriculture: Student Activities Volume II.

    ERIC Educational Resources Information Center

    Martin, Robert A., Ed.

    These student activities are designed to be used in a variety of places in the curriculum to provide a global perspective for students as they study agriculture. This document is not a unit of instruction; rather, teachers are encouraged to study the materials and decide which will be helpful in adding a global perspective to the learning…

  6. A Life-Course Perspective on Physical Activity Promotion: Applications and Implications

    ERIC Educational Resources Information Center

    Li, Kin-Kit; Cardinal, Bradley J.; Settersten, Richard A., Jr.

    2009-01-01

    This article illustrates how a life-course perspective can be infused more fully into the research field of physical activity promotion. A life-course perspective is particularly promising in connecting, organizing, and supplementing current knowledge and can potentially stimulate and direct future research and intervention efforts by using a…

  7. Skeletal Adaptation to Daily Activity: A Biochemical Perspective

    NASA Technical Reports Server (NTRS)

    Whalen, Robert T.; Dalton, Bonnie (Technical Monitor)

    2002-01-01

    Musculoskeletal forces generated by normal daily activity on Earth maintain the functional and structural properties of muscle and bone throughout most of one's adult life. A reduction in the level of cumulative daily loading caused by space flight, bed rest or spinal cord injury induces rapid muscle atrophy, functional changes in muscle, and bone resorption in regions subjected to the reduced loading. Bone cells in culture and bone tissue reportedly respond to a wide variety of non-mechanical and mechanical stimuli ranging, from electromagnetic fields, and hormones to small amplitude, high frequency vibrations, fluid flow, strain rate, and stress/strain magnitude. However, neither the transduction mechanism that transforms the mechanical input into a muscle or bone metabolic response nor the characteristics, of the loading history that directly or indirectly stimulates the cell is known. Identifying the factors contributing to the input stimulus will have a major impact on the design of effective countermeasures for long duration space flight. This talk will present a brief overview of current theories of bone remodeling and functional adaptation to mechanical loading. Work from our lab will be presented from the perspective of daily cumulative loading on Earth and its relationship to bone density and structure. Our objective is to use the tibia and calcaneus as model bone sites of cortical and cancellous bone adaptation, loaded daily by musculoskeletal forces in equilibrium with the ground reaction force. All materials that will be discussed are in the open scientific literature.

  8. Theoretical analysis of the relationship between positive/negative cooperativity and enzyme activation/inhibition.

    PubMed

    Ge, Hao; Qian, Min

    2009-09-01

    Cooperativity is one of the "paradigms" in enzyme kinetics and molecular biology. But the classical textbook treatment of enzyme kinetics always indeed separates the concepts of positive/negative cooperativity from enzyme activation/inhibition, at least partially. Few theoretical analysis of their relationship has been discussed, although its experimental investigations might date back at least to 1970s. In the present paper, we try to apply the change of free energy as a connective parameter for investigating the relationship between positive/negative cooperativity and enzyme activation/inhibition through several classic equilibrium binding models. It is explicitly shown that the terms of positive/negative cooperativity could be equivalently regarded as enzyme activation/inhibition of the saturation function induced by the substrate molecule itself rather than any other additional effectors. Moreover, both the degree of cooperativity phenomenon and the degree of enzyme activation/inhibition monotonically increase with the change of free energy. Note that this result is quite different from the idea of relating cooperativity to the concepts of "substrate activation/inhibition", which is identified when at high substrate concentrations the reaction rate decreases instead of tending towards the maximum velocity, since it always needs a second substrate molecule.

  9. Reality-Theoretical Models-Mathematics: A Ternary Perspective on Physics Lessons in Upper-Secondary School

    NASA Astrophysics Data System (ADS)

    Hansson, Lena; Hansson, Örjan; Juter, Kristina; Redfors, Andreas

    2015-07-01

    This article discusses the role of mathematics during physics lessons in upper-secondary school. Mathematics is an inherent part of theoretical models in physics and makes powerful predictions of natural phenomena possible. Ability to use both theoretical models and mathematics is central in physics. This paper takes as a starting point that the relations made during physics lessons between the three entities Reality, Theoretical models and Mathematics are of the outmost importance. A framework has been developed to sustain analyses of the communication during physics lessons. The study described in this article has explored the role of mathematics for physics teaching and learning in upper-secondary school during different kinds of physics lessons (lectures, problem solving and labwork). Observations are from three physics classes (in total 7 lessons) led by one teacher. The developed analytical framework is described together with results from the analysis of the 7 lessons. The results show that there are some relations made by students and teacher between theoretical models and reality, but the bulk of the discussion in the classroom is concerning the relation between theoretical models and mathematics. The results reported on here indicate that this also holds true for all the investigated organizational forms lectures, problem solving in groups and labwork.

  10. Multi-level Discourse Analysis in a Physics Teaching Methods Course from the Psychological Perspective of Activity Theory

    NASA Astrophysics Data System (ADS)

    Drumond Vieira, Rodrigo; Kelly, Gregory J.

    2014-11-01

    In this paper, we present and apply a multi-level method for discourse analysis in science classrooms. This method is based on the structure of human activity (activity, actions, and operations) and it was applied to study a pre-service physics teacher methods course. We argue that such an approach, based on a cultural psychological perspective, affords opportunities for analysts to perform a theoretically based detailed analysis of discourse events. Along with the presentation of analysis, we show and discuss how the articulation of different levels offers interpretative criteria for analyzing instructional conversations. We synthesize the results into a model for a teacher's practice and discuss the implications and possibilities of this approach for the field of discourse analysis in science classrooms. Finally, we reflect on how the development of teachers' understanding of their activity structures can contribute to forms of progressive discourse of science education.

  11. The spatial distribution of X-ray selected AGN in the Chandra deep fields: a theoretical perspective

    NASA Astrophysics Data System (ADS)

    Marulli, Federico; Bonoli, Silvia; Branchini, Enzo; Gilli, Roberto; Moscardini, Lauro; Springel, Volker

    2009-07-01

    We study the spatial distribution of X-ray selected active galactic nuclei (AGN) in the framework of hierarchical coevolution of supermassive black holes and their host galaxies and dark matter haloes. To this end, we have applied the theoretical model developed by Croton et al., De Lucia & Blaizot and Marulli et al. to the output of the Millennium Run and obtained hundreds of realizations of past light cones from which we have extracted realistic mock AGN catalogues that mimic the Chandra deep fields. We find that the model AGN number counts are in fair agreement with observations both in the soft and in the hard X-ray bands, except at fluxes <~10-15ergcm-2s-1, where the model systematically overestimates the observations. However, a large fraction of these faint objects are typically excluded from the spectroscopic AGN samples of the Chandra fields. We find that the spatial two-point correlation function predicted by the model is well described by a power-law relation out to 20h-1Mpc, in close agreement with observations. Our model matches the correlation length r0 of AGN in the Chandra Deep Field-North but underestimates it in the Chandra Deep Field-South. When fixing the slope to γ = 1.4, as in Gilli et al., the statistical significance of the mismatch is 2σ-2.5σ, suggesting that the predicted cosmic variance, which dominates the error budget, may not account for the different correlation length of the AGN in the two fields. However, the overall mismatch between the model and the observed correlation function decreases when both r0 and γ are allowed to vary, suggesting that more realistic AGN models and a full account of all observational errors may significantly reduce the tension between AGN clustering in the two fields. While our results are robust to changes in the model prescriptions for the AGN light curves, the luminosity dependence of the clustering is sensitive to the different light-curve models adopted. However, irrespective of the model

  12. Virulence factor activity relationships (VFARs): a bioinformatics perspective.

    PubMed

    Waseem, Hassan; Williams, Maggie R; Stedtfeld, Tiffany; Chai, Benli; Stedtfeld, Robert D; Cole, James R; Tiedje, James M; Hashsham, Syed A

    2017-03-06

    Virulence factor activity relationships (VFARs) - a concept loosely based on quantitative structure-activity relationships (QSARs) for chemicals was proposed as a predictive tool for ranking risks due to microorganisms relevant to water safety. A rapid increase in sequencing capabilities and bioinformatics tools has significantly increased the potential for VFAR-based analyses. This review summarizes more than 20 bioinformatics databases and tools, developed over the last decade, along with their virulence and antimicrobial resistance prediction capabilities. With the number of bacterial whole genome sequences exceeding 241 000 and metagenomic analysis projects exceeding 13 000 and the ability to add additional genome sequences for few hundred dollars, it is evident that further development of VFARs is not limited by the availability of information at least at the genomic level. However, additional information related to co-occurrence, treatment response, modulation of virulence due to environmental and other factors, and economic impact must be gathered and incorporated in a manner that also addresses the associated uncertainties. Of the bioinformatics tools, a majority are either designed exclusively for virulence/resistance determination or equipped with a dedicated module. The remaining have the potential to be employed for evaluating virulence. This review focusing broadly on omics technologies and tools supports the notion that these tools are now sufficiently developed to allow the application of VFAR approaches combined with additional engineering and economic analyses to rank and prioritize organisms important to a given niche. Knowledge gaps do exist but can be filled with focused experimental and theoretical analyses that were unimaginable a decade ago. Further developments should consider the integration of the measurement of activity, risk, and uncertainty to improve the current capabilities.

  13. Theoretical investigation of pillar[4]quinone as a cathode active material for lithium-ion batteries.

    PubMed

    Huan, Long; Xie, Ju; Chen, Ming; Diao, Guowang; Zhao, Rongfang; Zuo, Tongfei

    2017-04-01

    The applicability of a novel macrocyclic multi-carbonyl compound, pillar[4]quinone (P4Q), as the cathode active material for lithium-ion batteries (LIBs) was assessed theoretically. The molecular geometry, electronic structure, Li-binding thermodynamic properties, and the redox potential of P4Q were obtained using density functional theory (DFT) at the M06-2X/6-31G(d,p) level of theory. The results of the calculations indicated that P4Q interacts with Li atoms via three binding modes: Li-O ionic bonding, O-Li···O bridge bonding, and Li···phenyl noncovalent interactions. Calculations also indicated that, during the LIB discharging process, P4Q could yield a specific capacity of 446 mAh g(-1) through the utilization of its many carbonyl groups. Compared with pillar[5]quinone and pillar[6]quinone, the redox potential of P4Q is enhanced by its high structural stability as well as the effect of the solvent. These results should provide the theoretical foundations for the design, synthesis, and application of novel macrocyclic carbonyl compounds as electrode materials in LIBs in the future. Graphical Abstract Schematic representation of the proposed charge-discharge mechanism of Pillar[4]quinone as cathode for lithium-ion batteries.

  14. Potential amoebicidal activity of hydrazone derivatives: synthesis, characterization, electrochemical behavior, theoretical study and evaluation of the biological activity.

    PubMed

    Toledano-Magaña, Yanis; García-Ramos, Juan Carlos; Navarro-Olivarria, Marisol; Flores-Alamo, Marcos; Manzanera-Estrada, Mayra; Ortiz-Frade, Luis; Galindo-Murillo, Rodrigo; Ruiz-Azuara, Lena; Meléndrez-Luevano, Ruth Ma; Cabrera-Vivas, Blanca M

    2015-05-29

    Four new hydrazones were synthesized by the condensation of the selected hydrazine and the appropriate nitrobenzaldehyde. A complete characterization was done employing 1H- and 13C-NMR, electrochemical techniques and theoretical studies. After the characterization and electrochemical analysis of each compound, amoebicidal activity was tested in vitro against the HM1:IMSS strain of Entamoeba histolytica. The results showed the influence of the nitrobenzene group and the hydrazone linkage on the amoebicidal activity. meta-Nitro substituted compound 2 presents a promising amoebicidal activity with an IC50 = 0.84 μM, which represents a 7-fold increase in cell growth inhibition potency with respect to metronidazole (IC50 = 6.3 μM). Compounds 1, 3, and 4 show decreased amoebicidal activity, with IC50 values of 7, 75 and 23 µM, respectively, as a function of the nitro group position on the aromatic ring. The observed differences in the biological activity could be explained not only by the redox potential of the molecules, but also by their capacity to participate in the formation of intra- and intermolecular hydrogen bonds. Redox potentials as well as the amoebicidal activity can be described with parameters obtained from the DFT analysis.

  15. Emerging Vocabulary Learning: From a Perspective of Activities Facilitated by Mobile Devices

    ERIC Educational Resources Information Center

    Hu, Zengning

    2013-01-01

    This paper examines the current mobile vocabulary learning practice to discover how far mobile devices are being used to support vocabulary learning. An activity-centered perspective is undertaken, with the consideration of new practice against existing theories of learning activities including behaviorist activities, constructivist activities,…

  16. Employing an Activity-Theoretical Perspective to Localize an Educational Innovation in an Elementary School

    ERIC Educational Resources Information Center

    Lim, Cher Ping; Tay, Lee Yong; Hedberg, John

    2011-01-01

    Two grade 5 classes (11-12-year-olds) were introduced through an inquiry-based pedagogy to scientific ideas and concepts within a 3D game-like multi-user virtual environment (MUVE). This article explores how a particular set of strategies and conditions might encourage and sustain the use of the MUVE, Quest Atlantis (QA), as a problem-based…

  17. Connecting the solubility and CCN activation of complex organic aerosols: a theoretical study using solubility distributions

    NASA Astrophysics Data System (ADS)

    Riipinen, I.; Rastak, N.; Pandis, S. N.

    2015-06-01

    We present a theoretical study investigating the cloud activation of multicomponent organic particles. We modeled these complex mixtures using solubility distributions (analogous to volatility distributions in the VBS, i.e., volatility basis set, approach), describing the mixture as a set of surrogate compounds with varying water solubilities in a given range. We conducted Köhler theory calculations for 144 different mixtures with varying solubility range, number of components, assumption about the organic mixture thermodynamics and the shape of the solubility distribution, yielding approximately 6000 unique cloud condensation nucleus (CCN)-activation points. The results from these comprehensive calculations were compared to three simplifying assumptions about organic aerosol solubility: (1) complete dissolution at the point of activation; (2) combining the aerosol solubility with the molar mass and density into a single effective hygroscopicity parameter κ; and (3) assuming a fixed water-soluble fraction ϵeff. The complete dissolution was able to reproduce the activation points with a reasonable accuracy only when the majority (70-80%) of the material was dissolved at the point of activation. The single-parameter representations of complex mixture solubility were confirmed to be powerful semi-empirical tools for representing the CCN activation of organic aerosol, predicting the activation diameter within 10% in most of the studied supersaturations. Depending mostly on the condensed-phase interactions between the organic molecules, material with solubilities larger than about 0.1-100 g L-1 could be treated as soluble in the CCN activation process over atmospherically relevant particle dry diameters and supersaturations. Our results indicate that understanding the details of the solubility distribution in the range of 0.1-100 g L-1 is thus critical for capturing the CCN activation, while resolution outside this solubility range will probably not add

  18. Transfer and Conceptual Change: The Change Process from the Theoretical Perspectives of Coordination Classes and Phenomenological Primitives

    ERIC Educational Resources Information Center

    Ozdemir, Omer F.

    2013-01-01

    The purpose of this study is to understand the nature of pre-instructional knowledge transferred by students into problem situations and the change process on students' knowledge system during classroom discussions. This study was framed by two interrelated theoretical frameworks on knowledge structures, phenomenological primitives and…

  19. The Importance of Emotion in Theories of Motivation: Empirical, Methodological, and Theoretical Considerations from a Goal Theory Perspective

    ERIC Educational Resources Information Center

    Turner, Julianne C.; Meyer, Debra K.; Schweinle, Amy

    2003-01-01

    Despite its importance to educational psychology, prominent theories of motivation have mostly ignored emotion. In this paper, we review theoretical conceptions of the relation between motivation and emotion and discuss the role of emotion in understanding student motivation in classrooms. We demonstrate that emotion is one of the best indicators…

  20. Left inferior-parietal lobe activity in perspective tasks: identity statements.

    PubMed

    Arora, Aditi; Weiss, Benjamin; Schurz, Matthias; Aichhorn, Markus; Wieshofer, Rebecca C; Perner, Josef

    2015-01-01

    We investigate the theory that the left inferior parietal lobe (IPL) is closely associated with tracking potential differences of perspective. Developmental studies find that perspective tasks are mastered at around 4 years of age. Our first study, meta-analyses of brain imaging studies shows that perspective tasks specifically activate a region in the left IPL and precuneus. These tasks include processing of false belief, visual perspective, and episodic memory. We test the location specificity theory in our second study with an unusual and novel kind of perspective task: identity statements. According to Frege's classical logical analysis, identity statements require appreciation of modes of presentation (perspectives). We show that identity statements, e.g., "the tour guide is also the driver" activate the left IPL in contrast to a control statements, "the tour guide has an apprentice." This activation overlaps with the activations found in the meta-analysis. This finding is confirmed in a third study with different types of statements and different comparisons. All studies support the theory that the left IPL has as one of its overarching functions the tracking of perspective differences. We discuss how this function relates to the bottom-up attention function proposed for the bilateral IPL.

  1. A natural diterpenoid kamebacetal A with anti-tumor activity: Theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Tang, Fu-ming; Zhang, Yi-Heng; Chen, Zhong

    2010-06-01

    Kamebacetal A ( 1) is an ent-kaurane diterpenoid isolated from Isodon racemosa (Hemsl) Hara. This natural product exhibits significant cytotoxicity against human Bel-7402 and HO-8910 tumor cells. The geometrical conformation of 1 has been optimized at the B3LYP/6-311+G(d) level of theory. The results indicated that the calculated geometric parameters are close to the X-ray crystal structure. The theoretical 13C NMR chemical shifts of 1 were also calculated at the GIAO-B3LYP level of theory with different basis sets. The calculated NMR chemical shifts are in closer agreement with the experimental results. A molecular electrostatic potential (MEP) map was used in an attempt to identify key features of the kamebacetal A to account for its anti-tumor activity. MEP investigations reveal that compound 1, which shows anti-tumor activity, possesses electron-rich regions that extend over the hydroxyl and carbonyl groups of compound 1. The data generated in this study is valuable as it provides an insight into kamebacetal A molecular and structure-activity relationships.

  2. Theoretical perspectives concerning positive aspects of caring for elderly persons with dementia: stress/adaptation and existentialism.

    PubMed

    Farran, C J

    1997-04-01

    Research concerning caregivers of persons with dementia has predominantly been guided by a stress/adaptation paradigm. This paradigm, however, does not fully address the issue of how caregivers manage to do so well under difficult circumstances. Existentialism offers an alternate theoretical view for exploring this issue. This article compares and contrasts these two paradigms-their key elements, strengths, and limitations, and areas of convergence and divergence. It identifies implications for future theory development, research, and clinical practice.

  3. Perspectives

    ERIC Educational Resources Information Center

    Tarone, Elaine

    2013-01-01

    The topic of this "Perspectives" column is "Requiring a Proficiency Level as a Requirement for U.S. K-12 Teacher Licensure." In 1998, the American Council of Teachers of Foreign Languages (ACTFL) began to work with the National Council for Accreditation of Teacher Education (NCATE), which accredits teacher education programs…

  4. Child maltreatment, parent alcohol and drug-related problems, polydrug problems, and parenting practices: a test of gender differences and four theoretical perspectives.

    PubMed

    Locke, Thomas F; Newcomb, Michael

    2004-03-01

    The authors tested how adverse childhood experiences (child maltreatment and parent alcohol- and drug-related problems) and adult polydrug use (as a mediator) predict poor parenting in a community sample (237 mothers and 81 fathers). These relationships were framed within several theoretical perspectives, including observational learning, impaired functioning, self-medication, and parentification-pseudomaturity. Structural models revealed that child maltreatment predicted poor parenting practices among mothers. Parent alcohol- and drug-related problems had an indirect detrimental influence on mothers' parenting and practices through self-drug problems. Among fathers, emotional neglect experienced as a child predicted lack of parental warmth more parental neglect, and sexual abuse experienced as a child predicted a rejecting style of parenting.

  5. Theoretical and experimental investigation of actively Q-switched Nd:YAG 946 nm laser with considering ETU effects

    NASA Astrophysics Data System (ADS)

    Yan, R.; Yu, X.; Li, X.; Chen, D.; Yu, J.

    2012-09-01

    A theoretical model on actively Q-switched Nd3+-doped quasi-three-level laser including the energy transfer upconversion and the ground state reabsorption is developed. The analytical expressions of the fractional thermal loading and the average output power are obtained, and the influence of ETU effects on laser performance for different repetition rate is analyzed. The average output power and the thermal focal length of the Q-switched 946 nm laser are acquired in experiment. The good agreement between the experimental data and theoretical results demonstrates the reliability of the theoretical model.

  6. Mechanistic implications in the phosphatase activity of Mannich-based dinuclear zinc complexes with theoretical modeling.

    PubMed

    Sanyal, Ria; Zhang, Xuepeng; Kundu, Priyanka; Chattopadhyay, Tanmay; Zhao, Cunyuan; Mautner, Franz A; Das, Debasis

    2015-03-02

    An "end-off" compartmental ligand has been synthesized by an abnormal Mannich reaction, namely, 2-[bis(2-methoxyethyl)aminomethyl]-4-isopropylphenol yielding three centrosymmetric binuclear μ-phenoxozinc(II) complexes having the molecular formula [Zn2(L)2X2] (Zn-1, Zn-2, and Zn-3), where X = Cl(-), Br (-), and I (-), respectively. X-ray crystallographic analysis shows that the ZnO3NX chromophores in each molecule form a slightly distorted trigonal-bipyramidal geometry (τ = 0.55-0.68) with an intermetallic distance of 3.068, 3.101, and 3.083 Å (1-3, respectively). The spectrophotometrical investigation on their phosphatase activity established that all three of them possess significant hydrolytic efficiency. Michaelis-Menten-derived kinetic parameters indicate that the competitiveness of the rate of P-O bond fission employing the phosphomonoester (4-nitrophenyl)phosphate in 97.5% N,N-dimethylformamide is 3 > 1 > 2 and the kcat value lies in the range 9.47-11.62 s(-1) at 298 K. Theoretical calculations involving three major active catalyst forms, such as the dimer-cis form (D-Cis), the dimer-trans form (D-Trans), and the monoform (M-1 and M-2), systematically interpret the reaction mechanism wherein the dimer-cis form with the binuclear-bridged hydroxide ion acting as the nucleophile and one water molecule playing a role in stabilizing the leaving group competes as the most favored pathway.

  7. Burnout Prevention: A Humanistic Perspective and Structured Group Supervision Activity

    ERIC Educational Resources Information Center

    Lambie, Glenn W.

    2006-01-01

    The consequences of burnout, including therapeutic ineffectiveness, premature occupational attrition, depression, and substance abuse, are potentially serious for counselors, both personally and professionally. After identifying the characteristics of burnout in professional counseling and introducing a humanistic existential theoretical model of…

  8. Analyzing Number Composition and Decomposition Activities in Kindergarten from a Numeracy Perspective

    ERIC Educational Resources Information Center

    Tsamir, Pessia; Tirosh, Dina; Levenson, Esther; Tabach, Michal; Barkai, Ruthi

    2015-01-01

    This study explores two number composition and decomposition activities from a numeracy perspective. Both activities have the same mathematical structure but each employs different tools and contexts. Twenty kindergarten children engaged individually with these activities. Verbal utterances as well as actions of the child and interviewer were…

  9. Client-centred therapy, post-traumatic stress disorder and post-traumatic growth: theoretical perspectives and practical implications.

    PubMed

    Joseph, Stephen

    2004-03-01

    In practice it is not unusual for client-centred therapists to work with people who have experienced traumatic events. However, client-centred therapy is not usually considered within texts on traumatic stress and questions have been raised over the appropriateness of client-centred therapy with trauma survivors. The present study shows how, although he was writing well before the introduction of the term 'post-traumatic stress disorder', Carl Rogers provided a theory of therapy and personality that contains an account of threat-related psychological processes largely consistent with contemporary trauma theory. Rogers' theory provides the conceptual underpinnings to the client-centred and experiential ways of working with traumatized people. Furthermore, Rogers' theory provides an understanding of post-traumatic growth processes, and encourages therapists to adopt a more positive psychological perspective to their understanding of how people adjust to traumatic events.

  10. Students' Perceptions of Teaching in Context-based and Traditional Chemistry Classrooms: Comparing content, learning activities, and interpersonal perspectives

    NASA Astrophysics Data System (ADS)

    Overman, Michelle; Vermunt, Jan D.; Meijer, Paulien C.; Bulte, Astrid M. W.; Brekelmans, Mieke

    2014-07-01

    Context-based curriculum reforms in chemistry education are thought to bring greater diversity to the ways in which chemistry teachers organize their teaching. First and foremost, students are expected to perceive this diversity. However, empirical research on how students perceive their teacher's teaching in context-based chemistry classrooms, and whether this teaching differs from traditional chemistry lessons, is scarce. This study aims to develop our understanding of what teaching looks like, according to students, in context-based chemistry classrooms compared with traditional chemistry classrooms. As such, it might also provide a better understanding of whether teachers implement and attain the intentions of curriculum developers. To study teacher behaviour we used three theoretical perspectives deemed to be important for student learning: a content perspective, a learning activities perspective, and an interpersonal perspective. Data were collected from 480 students in 24 secondary chemistry classes in the Netherlands. Our findings suggest that, according to the students, the changes in teaching in context-based chemistry classrooms imply a lessening of the emphasis on fundamental chemistry and the use of a teacher-centred approach, compared with traditional chemistry classrooms. However, teachers in context-based chemistry classrooms seem not to display more 'context-based' teaching behaviour, such as emphasizing the relation between chemistry, technology, and society and using a student-centred approach. Furthermore, students in context-based chemistry classrooms perceive their teachers as having less interpersonal control and showing less affiliation than teachers in traditional chemistry classrooms. Our findings should be interpreted in the context of former and daily experiences of both teachers and students. As only chemistry is reformed in the schools in which context-based chemistry is implemented, it is challenging for both students and teachers to

  11. Locadiff with ambient seismic noise : theoretical background and application to monitoring volcanoes and active faults.

    NASA Astrophysics Data System (ADS)

    Larose, Eric; Obermann, Anne; Planes, Thomas; Rossetto, Vincent; Margerin, Ludovic; Sens-Schoenfelder, Christoph; Campillo, Michel

    2015-04-01

    This contribution will cover recent theoretical, numerical, and field data processing developments aiming at modeling how coda waves are perturbed (in phase and amplitude) by mechanical changes in the crust. Using continuous ambient seismic noise, we cross-correlate data every day and compare the coda of the correlograms. We can relative velocity changes and waveform decorrelation along the year, that are related to mechanical changes in the shallow crust, associated to the seismic or volcanic activity, but also to environmental effects such as hydrology. Bibliography : Anne Obermann, Thomas Planes, Eric Larose and Michel Campillo, Imaging pre- and co-eruptive structural changes of a volcano with ambient seismic noise, J. Geophys. Res. 118 6285-6294 (2013). A. Obermann, B. Froment, M. Campillo, E. Larose, T. Planès, B. Valette, J. H. Chen, and Q. Y. Liu, Seismic noise correlations to image structural and mechanical changes associated with the Mw7.9 2008-Wenchuan earthquake, J. Geophys. Res. Solid Earth, 119, 1-14,(2014). Thomas Planès, Eric Larose, Ludovic Margerin, Vincent Rossetto, Christoph Sens-Schoenfelder, Decorrelation and phase-shift of coda waves induced by local changes : Multiple scattering approach and numerical validation, Waves in Random and Complex Media 24, 99-125, (2014)

  12. Application of theoretical models to active and passive remote sensing of saline ice

    NASA Technical Reports Server (NTRS)

    Han, H. C.; Kong, Jin AU; Shin, Robert T.; Nghiem, Son V.; Kwok, R.

    1992-01-01

    The random medium model is used to interpret the polarimetric active and passive measurements of saline ice. The ice layer is described as a host ice medium embedded with randomly distributed inhomogeneities, and the underlying sea water is considered as a homogeneous half-space. The scatterers in the ice layer are modeled with an ellipsoidal correlation function. The orientation of the scatterers is vertically aligned and azimuthally random. The strong permittivity fluctuation theory is employed to calculate the effective permittivity and the distorted Born approximation is used to obtain the polarimetric scattering coefficients. We also calculate the thermal emissions based on the reciprocity and energy conservation principles. The effects of the random roughness at the air-ice, and ice-water interfaces are accounted for by adding the surface scattering to the volume scattering return incoherently. The above theoretical model, which has been successfully applied to analyze the radar backscatter data of the first-year sea ice near Point Barrow, AK, is used to interpret the measurements performed in the CRRELEX program.

  13. Spaced education activates students in a theoretical radiological science course: a pilot study

    PubMed Central

    2012-01-01

    education to a face-to-face theoretical radiological science course activates students in a way that they spend significantly more time on keeping busy with the learning content. PMID:22621409

  14. An Exploratory Study of Elementary Classroom Teachers' Physical Activity Promotion from a Social Learning Perspective

    ERIC Educational Resources Information Center

    Webster, Collin A.; Buchan, Heather; Perreault, Melanie; Doan, Rob; Doutis, Panayiotis; Weaver, Robert Glenn

    2015-01-01

    Despite its recommended use, physical activity promotion in the academic classroom (PAPAC) has received little attention in terms of the factors that help to facilitate it. In this study, a social learning perspective was adopted to examine the role of physical activity biographies in generalist classroom teachers' (CTs) PAPAC. CTs (N = 213) were…

  15. Student Views on Assessment Activities: Perspectives from Their Experience on an Undergraduate Programme

    ERIC Educational Resources Information Center

    Healy, Margaret; McCutcheon, Maeve; Doran, John

    2014-01-01

    Research on assessment activities has considered student responses to specific initiatives, but broader concerns underlying these responses have not been fully explored. Using a survey methodology, this paper explores how students view assessment activities, from the perspective of their experience on a four-year undergraduate programme,…

  16. A theoretical perspective on the accuracy of rotational resonance (R 2)-based distance measurements in solid-state NMR

    NASA Astrophysics Data System (ADS)

    Pandey, Manoj Kumar; Ramachandran, Ramesh

    2010-03-01

    The application of solid-state NMR methodology for bio-molecular structure determination requires the measurement of constraints in the form of 13C-13C and 13C-15N distances, torsion angles and, in some cases, correlation of the anisotropic interactions. Since the availability of structurally important constraints in the solid state is limited due to lack of sufficient spectral resolution, the accuracy of the measured constraints become vital in studies relating the three-dimensional structure of proteins to its biological functions. Consequently, the theoretical methods employed to quantify the experimental data become important. To accentuate this aspect, we re-examine analytical two-spin models currently employed in the estimation of 13C-13C distances based on the rotational resonance (R 2) phenomenon. Although the error bars for the estimated distances tend to be in the range 0.5-1.0 Å, R 2 experiments are routinely employed in a variety of systems ranging from simple peptides to more complex amyloidogenic proteins. In this article we address this aspect by highlighting the systematic errors introduced by analytical models employing phenomenological damping terms to describe multi-spin effects. Specifically, the spin dynamics in R 2 experiments is described using Floquet theory employing two different operator formalisms. The systematic errors introduced by the phenomenological damping terms and their limitations are elucidated in two analytical models and analysed by comparing the results with rigorous numerical simulations.

  17. Activities of the O&M committee history & future perspectives

    SciTech Connect

    Poulis, D.S.

    1996-12-01

    This paper gives an overview of the Committee on Operation and Maintenance of Nuclear Power Plants, hereafter referred to as the O&M Committee, formed in June 1975 when the American National Standard Institute`s Committee on Reactor Plants and their Maintenance was disbanded. The O&M Committee`s history, structure, current focus and future perspectives will be presented. The purpose of this paper is to give information to industry and the public of the Committee`s on-going effort to make accurate and timely responses to the needs of the nuclear industry.

  18. Developing policy solutions for a more active nation: Integrating economic and public health perspectives.

    PubMed

    Bleich, Sara N; Sturm, Roland

    2009-10-01

    Both economic and public health/medical perspectives play an important role in the policy process but often approach policy questions in an incompatible way. Harnessing any synergy requires an understanding of the other perspective. We begin by comparing and contrasting the economic and public health perspectives, including introducing relevant economic concepts. We next identify economic considerations for the development of environmental incentives that promote physical activity. We then assess features of the political environment which could impact the success of policy alternatives aimed at increasing physical activity. We conclude with several policy levers that may promote active living. Throughout the manuscript, we use the term economics to refer to classical economics and utility maximization rather than behavioral economics. In addition, we focus mostly on normative economics (which offers prescriptions for what should be done) rather than positive economics (which offers predictions of economic outcomes conditional on various hypothetical scenarios).

  19. Understanding the colloidal dispersion stability of 1D and 2D materials: Perspectives from molecular simulations and theoretical modeling.

    PubMed

    Lin, Shangchao; Shih, Chih-Jen; Sresht, Vishnu; Govind Rajan, Ananth; Strano, Michael S; Blankschtein, Daniel

    2016-08-03

    The colloidal dispersion stability of 1D and 2D materials in the liquid phase is critical for scalable nano-manufacturing, chemical modification, composites production, and deployment as conductive inks or nanofluids. Here, we review recent computational and theoretical studies carried out by our group to model the dispersion stability of 1D and 2D materials, including single-walled carbon nanotubes, graphene, and graphene oxide in aqueous surfactant solutions or organic solvents. All-atomistic (AA) molecular dynamics (MD) simulations can probe the molecular level details of the adsorption morphology of surfactants and solvents around these materials, as well as quantify the interaction energy between the nanomaterials mediated by surfactants or solvents. Utilizing concepts from reaction kinetics and diffusion, one can directly predict the rate constants for the aggregation kinetics and dispersion life times using MD outputs. Furthermore, the use of coarse-grained (CG) MD simulations allows quantitative prediction of surfactant adsorption isotherms. Combined with the Poisson-Boltzmann equation, the Langmuir isotherm, and the DLVO theory, one can directly use CGMD outputs to: (i) predict electrostatic potentials around the nanomaterial, (ii) correlate surfactant surface coverages with surfactant concentrations in the bulk dispersion medium, and (iii) determine energy barriers against coagulation. Finally, we discuss challenges associated with studying emerging 2D materials, such as, hexagonal boron nitride (h-BN), phosphorene, and transition metal dichalcogenides (TMDCs), including molybdenum disulfide (MoS2). An outlook is provided to address these challenges with plans to develop force-field parameters for MD simulations to enable predictive modeling of emerging 2D materials in the liquid phase.

  20. Double Stimulation in Strategic Concept Formation: An Activity-Theoretical Analysis of Business Planning in a Small Technology Firm

    ERIC Educational Resources Information Center

    Virkkunen, Jaakko; Ristimaki, Paivi

    2012-01-01

    In this article, we study the relationships between culturally existing general strategy concepts and a small information and communication technology firm's specific strategic challenge in its management team's search for a new strategy concept. We apply three theoretical ideas of cultural historical activity theory: (a) the idea of double…

  1. New dicoumarol sodium compound: crystal structure, theoretical study and tumoricidal activity against osteoblast cancer cells

    PubMed Central

    2013-01-01

    Background Enormous interest had been paid to the coordination chemistry of alkali and alkaline metal ions because of their role inside body viz; their Li+/Na+ exchange inside the cell lead to different diseases like neuropathy, hypertension, microalbuminuria, cardiac and vascular hypertrophy, obesity, and insulin resistance. It has been presumed that alkali metal ions (whether Na+ or K+) coordinated to chelating ligands can cross the hydrophobic cell membrane easily and can function effectively for depolarizing the ion difference. This unique function was utilized for bacterial cell death in which K+ has been found coordinated valinomycin (antibiotic). Results Distinct sodium adduct (1) with dicoumarol ligand, 4-Hydroxy-3-[(4-hydroxy-2-oxo-4a,8a-dihydro-2H-chromen-3-yl)-phenyl-methyl]-chromen-2-one (L) is isolated from the saturated solution of sodium methoxide. Single crystal X-ray diffraction studies of the adduct reveals that sodium is in the form of cation attached to a methoxide, methanol and a dicoumarol ligand where carbonyl functional groups of the coumarin derivative are acting as bridges. The sodium compound (1) is also characterized by IR, 1H-NMR, and 13C{1H}-NMR spectroscopic techniques. The composition is confirmed by elemental analysis. DFT study for 1 has been carried out using B3LYP/6-13G calculations which shown the theoretical confirmation of the various bond lengths and bond angles. Both the compounds were studied subsequently for the U2OS tumoricidal activity and it was found that L has LD50 value of 200 μM whereas the sodium analog cytotoxicity did not drop down below 60%. Conclusion A sodium analogue (1) with medicinally important dicoumarol ligand (L) has been reported. The crystal structure and DFT study confirm the formation of cationic sodium compound with dicoumarol. The ligand was found more active than the sodium analog attributed to the instability of 1 in solution state. Coumarin compound with sodium was observed to be less

  2. Quantitative structure-activity relationship modeling of polycyclic aromatic hydrocarbon mutagenicity by classification methods based on holistic theoretical molecular descriptors.

    PubMed

    Gramatica, Paola; Papa, Ester; Marrocchi, Assunta; Minuti, Lucio; Taticchi, Aldo

    2007-03-01

    Various polycyclic aromatic hydrocarbons (PAHs), ubiquitous environmental pollutants, are recognized mutagens and carcinogens. A homogeneous set of mutagenicity data (TA98 and TA100,+S9) for 32 benzocyclopentaphenanthrenes/chrysenes was modeled by the quantitative structure-activity relationship classification methods k-nearest neighbor and classification and regression tree, using theoretical holistic molecular descriptors. Genetic algorithm provided the selection of the best subset of variables for modeling mutagenicity. The models were validated by leave-one-out and leave-50%-out approaches and have good performance, with sensitivity and specificity ranges of 90-100%. Mutagenicity assessment for these PAHs requires only a few theoretical descriptors of their molecular structure.

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

    PubMed

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

    2015-05-19

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

  4. Activity Engagement: Perspectives from Nursing Home Residents with Dementia

    PubMed Central

    Tak, Sunghee H.; Kedia, Satish; Tongumpun, Tera Marie; Hong, Song Hee

    2014-01-01

    Engagement in social and leisure activities is an indicator of quality of life and well-being in nursing homes. There are few studies in which nursing home residents with dementia self-reported their experiences in activity engagement. This qualitative study describes types of current activity involvement and barriers to activities as perceived by nursing home residents with dementia. Thirty-one residents participated in short, open-ended interviews and six in in-depth interviews. Thematic content analysis showed that participants primarily depended on activities organized by their nursing homes. Few participants engaged in self-directed activities such as walking, visiting other residents and family members, and attending in church services. Many residents felt they had limited opportunities and motivation for activities. They missed past hobbies greatly but could not continue them due to lack of accommodation and limitation in physical function. Environmental factors, along with fixed activity schedule, further prevented them from engaging in activities. Residents with dementia should be invited to participate in activity planning and have necessary assistance and accommodation in order to engage in activities that matter to them. Based on the findings, a checklist for individualizing and evaluating activities for persons with dementia is detailed. PMID:25489122

  5. DMSO-Li2O2 Interface in the Rechargeable Li-O2 Battery Cathode: Theoretical and Experimental Perspectives on Stability.

    PubMed

    Schroeder, Marshall A; Kumar, Nitin; Pearse, Alexander J; Liu, Chanyuan; Lee, Sang Bok; Rubloff, Gary W; Leung, Kevin; Noked, Malachi

    2015-06-03

    One of the greatest obstacles for the realization of the nonaqueous Li-O2 battery is finding a solvent that is chemically and electrochemically stable under cell operating conditions. Dimethyl sulfoxide (DMSO) is an attractive candidate for rechargeable Li-O2 battery studies; however, there is still significant controversy regarding its stability on the Li-O2 cathode surface. We performed multiple experiments (in situ XPS, FTIR, Raman, and XRD) which assess the stability of the DMSO-Li2O2 interface and report perspectives on previously published studies. Our electrochemical experiments show long-term stable cycling of a DMSO-based operating Li-O2 cell with a platinum@carbon nanotube core-shell cathode fabricated via atomic layer deposition, specifically with >45 cycles of 40 h of discharge per cycle. This work is complemented by density functional theory calculations of DMSO degradation pathways on Li2O2. Both experimental and theoretical evidence strongly suggests that DMSO is chemically and electrochemically stable on the surface of Li2O2 under the reported operating conditions.

  6. Adolescents' Perspectives on the Barriers and Facilitators of Physical Activity: A Systematic Review of Qualitative Studies

    ERIC Educational Resources Information Center

    Martins, João; Marques, Adilson; Sarmento, Hugo; Carreiro da Costa, Francisco

    2015-01-01

    This article examined qualitative studies of adolescents' perspectives about the facilitators and barriers of physical activity, published from 2007 to 2014. A systematic review of "Web of Science", "EBSCO", "Psychinfo" and "ERIC" databases was performed according to Preferred Reporting Items for Systematic…

  7. An Activity Theory Perspective on Student-Reported Contradictions in International Telecollaboration

    ERIC Educational Resources Information Center

    Basharina, Olga K.

    2007-01-01

    This process-oriented study focuses on contradictions that emerged in a WebCT bulletin board collaboration among English learners from Japan, Mexico and Russia, and explains them from the perspective of activity theory (Leont'ev, 1978, 1981; Engestrom, 1987, 1999). The study identified a) two "intra-cultural" contradictions--to post or…

  8. Language-Learning Motivation during Short-Term Study Abroad: An Activity Theory Perspective

    ERIC Educational Resources Information Center

    Allen, Heather Willis

    2010-01-01

    This study investigated the development of language-learning motivation during short-term study abroad (SA) for six intermediate-level students of French. Taking an activity theory perspective, findings demonstrated that one of two orientations motivated participants to study or continue studying French at the college level: linguistic motives or…

  9. Photonic Network R&D Activities in Japan-Current Activities and Future Perspectives

    NASA Astrophysics Data System (ADS)

    Kitayama, Ken-Ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-Ichi; Onaka, Hiroshi; Namiki, Shu; Aoyama, Tomonori

    2005-10-01

    R&D activities on photonic networks in Japan are presented. First, milestones in current ongoing R&D programs supported by Japanese government agencies are introduced, including long-distance and wavelength division multiplexing (WDM) fiber transmission, wavelength routing, optical burst switching (OBS), and control-plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP-over-WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R&D programs for photonic networks over the next 5 years until 2010, by focusing on the report that has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R&D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis, through the customer's initiative to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

  10. A new perspective on the radio active zone at the Galactic center - feedback from nuclear activities

    NASA Astrophysics Data System (ADS)

    Zhao, J.-H.; Morris, M. R.; Goss, W. M.

    2014-05-01

    Based on our deep image of Sgr A using broadband data observed with the VLA† at 6 cm, we present a new perspective of the radio bright zone at the Galactic center. We further show the radio detection of the X-ray Cannonball, a candidate neutron star associated with the Galactic center SNR Sgr A East. The radio image is compared with the Chandra X-ray image to show the detailed structure of the radio counterparts of the bipolar X-ray lobes. The bipolar lobes are likely produced by the winds from the activities within Sgr A West, which could be collimated by the inertia of gas in the CND, or by the momentum driving of Sgr A*; and the poloidal magnetic fields likely play an important role in the collimation. The less-collimated SE lobe, in comparison to the NW one, is perhaps due to the fact that the Sgr A East SN might have locally reconfigured the magnetic field toward negative galactic latitudes. In agreement with the X-ray observations, the time-scale of ˜1 × 104 yr estimated for the outermost radio ring appears to be comparable to the inferred age of the Sgr A East SNR.

  11. [Research and educational activities through perspective of pharmacognosy].

    PubMed

    Ito, Michiho

    2010-05-01

    The research field of pharmacognosy covers a wide variety of subjects based on a knowledge of natural medicines and extends its influence in all surrounding directions. Pharmacognosy itself is generally regarded as one of the branches of pharmaceutical science although the processes to achieve the objectives are not always analytical as are other branches in this field. The extraordinarily long history and broad view provide researchers opportunities to conduct unique projects which can enhance the perspective of the subject in the future. Fieldwork is one feature of scientific research and is viewed as more valuable to projects in pharmacognosy than to those in other fields of pharmaceutical sciences. The frame of my research has been formed around fieldwork; projects targeted are achieved based on information and samples gathered through this means, and further studies are suggested by the ideas obtained. Some of the results and experiences gathered in these projects are described in this article for discussion of the future image of the pharmacognosial field.

  12. Student Activism within Christian College Cultures: A Symbolic Interactionist Perspective

    ERIC Educational Resources Information Center

    Cole, Brian E.

    2014-01-01

    This study contributes to the understanding of the structural and cultural influences of Christian college environments on student activism through the framework of symbolic interactionism (Blumer, 1969; Mead, 1934). The goal of this research was to examine how the students at Christian institutions understand and engage in activism within their…

  13. Physical Activity in the Mass Media: An Audience Perspective

    ERIC Educational Resources Information Center

    Smith, Ben J.; Bonfiglioli, Catriona M. F.

    2015-01-01

    Physical activity's role in promoting health is highlighted in public health campaigns, news and current affairs, reality television and other programs. An investigation of audience exposure, beliefs and reactions to media portrayals of physical activity offers insights into the salience and influence of this communication. An audience reception…

  14. Examining "Active" Procrastination from a Self-Regulated Learning Perspective

    ERIC Educational Resources Information Center

    Cao, Li

    2012-01-01

    This study examined the notion that active procrastinators are a positive type of procrastinators who possess desirable characteristics similar to non-procrastinators, but different from the traditional passive procrastinators. A two-step procedure was followed to categorise university students (N = 125) as active procrastinators, passive…

  15. Girls' Perspectives: Physical Activity and Self-Esteem.

    ERIC Educational Resources Information Center

    Jaffee, Lynn; Manzer, Rebecca

    1992-01-01

    The relationship between activity and positive self-esteem in girls 9 to 12 years of age was explored in this study. The hypothesis was that the positive relationship between physical activity and positive self-esteem which exists for women also exists for girls. A secondary goal was to gain insight into some of the factors that are associated…

  16. Practising Active Science with Child Refugees: A Clinical Perspective

    ERIC Educational Resources Information Center

    Perrier, Frédéric

    2004-01-01

    In this paper, pilot sessions in Rwanda and Nepal are analysed to evaluate the therapeutic benefit of active science for traumatised child refugees. The nature of the activities, choice of tools, organisation of the sessions, group size, and the role of the educators are investigated. Despite the lack of quantitative assessment, practical…

  17. Physical activity in the mass media: an audience perspective.

    PubMed

    Smith, Ben J; Bonfiglioli, Catriona M F

    2015-04-01

    Physical activity's role in promoting health is highlighted in public health campaigns, news and current affairs, reality television and other programs. An investigation of audience exposure, beliefs and reactions to media portrayals of physical activity offers insights into the salience and influence of this communication. An audience reception study was conducted involving in-depth interviews with 46 adults in New South Wales, Australia. The sample was stratified by gender, age group, area of residence and body mass index. Most respondents could only recall media coverage of physical activity with prompting. Television was the primary channel of exposure, with reality television the dominant source, followed by news programs and sports coverage. The messages most readily recalled were the health risks of inactivity, especially obesity, and the necessity of keeping active. Physical activity was regarded as a matter of personal volition, or for children, parental responsibility. Respondents believed that the media had given physical activity inadequate attention, focused too heavily on risks and not provided practical advice. In Australia, there is a need to counter the framing of physical activity by reality television, and engage the media to generate understanding of the socioecological determinants of inactivity. Physical activity campaigns should deliver positive and practical messages.

  18. Optics, mechanics, and energetics of two-dimensional MoS2 nanostructures from a theoretical perspective.

    PubMed

    Joswig, Jan-Ole; Lorenz, Tommy; Wendumu, Tsegabirhan Berhane; Gemming, Sibylle; Seifert, Gotthard

    2015-01-20

    CONSPECTUS: Nanostructures based on molybdenum disulfide (MoS2) are by far the most common and well-studied systems among two-dimensional (2D) semiconducting materials. Although still being characterized as a "promising material", catalytic activity of MoS2 nanostructures has been found, and applications in lubrication processes are pursued. Because exfoliation techniques have improved over the past years, monolayer MoS2 is easily at hand; thus, experimental studies on its electronic properties and applicability are in scientific focus, and some MoS2-based electronic devices have been reported already. Additionally, the improvement of atomic force microscopy led to nanoindentation experiments, in which the exceptional mechanical properties of MoS2 could be confirmed. In this Account, we review recent results from density-functional based calculations on several MoS2-based nanostructures; we have chosen to follow several experimental routes focusing on different nanostructures and their specific properties. MoS2-based triangular nanoflakes are systems that are experimentally well described and studied with a special focus on their optical absorption. The interpretation of our calculations fits well to the experimental picture: the absorption peaks in the visible light range show a quantum-confinement effect; they originate from excitations into the edge states. Additionally, delocalized metallic-like states are present close to the Fermi level, which do not contribute to photoabsorption in the visible range. Additionally, nanoindentation experiments have been simulated to obtain mechanical properties of the MoS2 material and to study the influence of deformation on the system's electronics. In these molecular-dynamics simulations, a tip penetrates a MoS2 monolayer, and the obtained Young's modulus and breaking stress agree very well with experimentally obtained values. Whereas the structural properties, such as bond lengths and layer contraction, vary locally

  19. Experimental verification of a theoretical model of an active cladding optical fiber fluorosensor

    NASA Technical Reports Server (NTRS)

    Albin, Sacharia; Briant, Alvin L.; Egalon, Claudio O.; Rogowski, Robert S.; Nankung, Juock S.

    1993-01-01

    Experiments were conducted to verify a theoretical model on the injection efficiency of sources in the cladding of an optical fiber. The theoretical results predicted an increase in the injection efficiency for higher differences in refractive indices between the core and cladding. The experimental apparatus used consisted of a glass rod 50 cm long, coated at one end with a thin film of fluorescent substance. The fluorescent substance was excited with side illumination, perpendicular to the rod axis, using a 476 nm Argon-ion laser. Part of the excited fluorescence was injected into the core and guided to a detector. The signal was measured for several different cladding refractive indices. The cladding consisted of sugar dissolved in water and the refractive index was changed by varying the sugar concentration in the solution. The results indicate that the power injected into the rod, due to evanescent wave injection, increases with the difference in refractive index which is in qualitative agreement with theory.

  20. A theoretical/experimental program to develop active optical pollution sensors

    NASA Technical Reports Server (NTRS)

    Mills, F. S.; Blais, R. N.; Kindle, E. C.

    1977-01-01

    Light detection and ranging (LIDAR) technology was applied to the assessment of air quality, and its usefulness was evaluated by actual field tests. Necessary hardware was successfully constructed and operated in the field. Measurements of necessary physical parameters, such as SO2 absorption coefficients were successfully completed and theoretical predictions of differential absorption performance were reported. Plume modeling improvements were proposed. A full scale field test of equipment, data analysis and auxiliary data support was conducted in Maryland during September 1976.

  1. Perspective: On the active site model in computational catalyst screening

    NASA Astrophysics Data System (ADS)

    Reuter, Karsten; Plaisance, Craig P.; Oberhofer, Harald; Andersen, Mie

    2017-01-01

    First-principles screening approaches exploiting energy trends in surface adsorption represent an unparalleled success story in recent computational catalysis research. Here we argue that our still limited understanding of the structure of active sites is one of the major bottlenecks towards an ever extended and reliable use of such computational screening for catalyst discovery. For low-index transition metal surfaces, the prevalently chosen high-symmetry (terrace and step) sites offered by the nominal bulk-truncated crystal lattice might be justified. For more complex surfaces and composite catalyst materials, computational screening studies will need to actively embrace a considerable uncertainty with respect to what truly are the active sites. By systematically exploring the space of possible active site motifs, such studies might eventually contribute towards a targeted design of optimized sites in future catalysts.

  2. Perspectives.

    ERIC Educational Resources Information Center

    Bandy, Patricia, Ed.

    Designed to encourage informed and critical thinking on contemporary political issues and processes, the articles, case studies, and activities in this student handbook can be incorporated into secondary school social studies units on government or current events. Eight chapters cover the presidency, the federal bureaucracy, the Congress, the…

  3. Novel perspectives on non-canonical inflammasome activation

    PubMed Central

    Diamond, Catherine Emma; Khameneh, Hanif Javanmard; Brough, David; Mortellaro, Alessandra

    2015-01-01

    Inflammasomes are cytosolic multi-protein complexes that regulate the secretion of the proinflammatory cytokines, IL-1β and IL-18, and induce pyroptosis, an inflammatory form of cell death. The NLRP3 inflammasome is the most well-characterized member of this family and functions by sensing intracellular pathogen- and damage-associated molecular patterns and activating caspase-1, which processes the biologically inactive IL-1β and IL-18 precursors into active cytokines. Recent studies have identified an alternative mechanism of inflammasome activation, termed the non-canonical inflammasome, which is triggered by cytosolic sensing of lipopolysaccharide (LPS) derived from bacteria that have escaped phagolysosomes. This pathway is independent of Toll-like receptor 4 (TLR4), the well-known extracellular receptor for LPS, but instead depends on the inflammatory protease, caspase-11. Although our understanding of caspase-11 activation is still in its infancy, it appears to be an essential mediator of septic shock and attenuates intestinal inflammation. In this review, we bring together the latest data on the roles of caspase-11 and the mechanisms underlying caspase-11-mediated activation of the non-canonical inflammasome, and consider the implications of this pathway on TLR4-independent immune responses to LPS. PMID:27471719

  4. Neutrino physics: A theoretical perspective

    SciTech Connect

    Marciano, W.J.

    1987-04-01

    Experimental measurements of sin/sup 2/theta/sub W/ are surveyed. They are shown to test electroweak unification at the quantum loop level and constrain new physics beyond the standard model. Neutrino oscillations are also examined in the framework of 3 generation mixing. Searches for nu/sub ..mu../ ..-->.. nu/sub tau/ oscillation at aceelerator facilities are advocated.

  5. Development of a theoretical model describing sonoporation activity of cells exposed to ultrasound in the presence of contrast agents

    PubMed Central

    Forbes, Monica M.; O’Brien, William D.

    2012-01-01

    Sonoporation uses ultrasound, with the aid of ultrasound contrast agents (UCAs), to enhance cell permeabilization, thereby allowing delivery of therapeutic compounds noninvasively into specific target cells. The objective of this study was to determine if a computational model describing shear stress on a cell membrane due to microstreaming would successfully reflect sonoporation activity with respect to the peak rarefactional pressure. The theoretical models were compared to the sonoporation results from Chinese hamster ovary cells using Definity® at 0.9, 3.15, and 5.6 MHz and were found to accurately describe the maximum sonoporation activity, the pressure where a decrease in sonoporation activity occurs, and relative differences between maximum activity and the activity after that decrease. Therefore, the model supports the experimental findings that shear stress on cell membranes secondary to oscillating UCAs results in sonoporation. PMID:22501051

  6. Spectral perspective on the electromagnetic activity of cells.

    PubMed

    Kučera, Ondrej; Červinková, Kateřina; Nerudová, Michaela; Cifra, Michal

    2015-01-01

    In this mini-review, we summarize the current hypotheses, theories and experimental evidence concerning the electromagnetic activity of living cells. We systematically classify the bio-electromagnetic phenomena in terms of frequency and we assess their general acceptance in scientific community. We show that the electromagnetic activity of cells is well established in the low frequency range below 1 kHz and on optical wavelengths, while there is only limited evidence for bio-electromagnetic processes in radio- frequency and millimeter-wave ranges. This lack of generally accepted theory or trustful experimental results is the cause for controversy which accompanies this topic. We conclude our review with the discussion of the relevance of the electromagnetic activity of cells to human medicine.

  7. Students' and experts' perspectives on three learning and teaching activities.

    PubMed

    Chan, Zenobia C Y

    2014-09-01

    Nursing is a profession that closely related to human life, and nurses are required to demonstrate critical thinking and creativity in providing health care services. However, traditional teaching approaches usually limit students' autonomy and freedom of expressing their thoughts and feelings. In order to develop the corresponding competence of nursing students, I adopted three teaching innovations, namely writing poems, composing songs, and using role plays in a nursing problem-based learning class in a university in Hong Kong. According to students' reflective notes and comments from two international expert reviewers, participating in these activities is a valuable experience and students were able to develop clinical reasoning, empathy, team spirit, motivation to learn, creativity, and ability to summarise and reconstruct knowledge. It is hoped that more innovative learning activities will be implemented, to prepare professional and ethical nurses in the future. It is also hoped that this study could provide other PBL educators some insights in innovative problem-based learning activities.

  8. Perezhivanie and classroom discourse: a cultural-historical perspective on "Discourse of design based science classroom activities"

    NASA Astrophysics Data System (ADS)

    Adams, Megan; March, Sue

    2015-06-01

    Flavio Azevedo, Peggy Martalock and Tugba Keser challenge the `argumentation focus of science lessons' and propose that through a `design-based approach' emergent conversations with the teacher offer possibilities for different types of discussions to enhance pedagogical discourse in science classrooms. This important paper offers a "preliminary contribution to a general theory" regarding the link between activity types and discourse practices. Azevedo, Martalock and Keser offer a general perspective with a sociocultural framing for analysis of classroom discourse. Interestingly the specific concepts drawn upon are from conversation analysis; there are few sociocultural concepts explored in detail. Therefore, in this article we focus on a cultural historical (Vygotsky in The collected works of L. S. Vygotsky. The history and development of higher mental functions, vol 4. Plenum Press, New York, 1987; The Vygotsky reader. Black, Cambridge, 1994) methodology to explore, analyse and explain how we would use a different theoretical lens. We argue that a cultural historical reading of argumentation in science lessons and design based activity will expand Azevedo, Martalock and Keser's proposed general theory of activity types and discourse practices. Specifically, we use Lev Vygotksy's idea of perezhivanie as the unit of analysis to reconceptualise this important paper. We focus on the holistic category of students' emotional experience through discourse while developing scientific awareness.

  9. Cooperating Teachers' Perspectives of Student Teaching Skills and Activities

    ERIC Educational Resources Information Center

    Smalley, Scott W.; Retallick, Michael S.; Paulsen, Thomas H.

    2015-01-01

    The purpose of this study was to determine the extent to which cooperating teachers deem required student teaching skills and activities relevant to the agricultural education student teaching experience. The population for this descriptive study consisted of individuals who served as cooperating teachers in Iowa and South Dakota during the last 5…

  10. Physical Activity Interventions for Adolescents: An Ecological Perspective

    ERIC Educational Resources Information Center

    Perry, Cynthia K.; Garside, Hailey; Morones, Sandra; Hayman, Laura L.

    2012-01-01

    Many factors contribute to the decline in physical activity (PA) observed during adolescence. We used an ecological framework to review 30 publications of PA interventions published between 1977 and 2009 targeting youth aged 12-18 years (19 PA interventions). We included studies that measured a primary outcome of PA and also examined intervening…

  11. Black Educational Activism for Community Empowerment: International Leadership Perspectives

    ERIC Educational Resources Information Center

    Wilson, Camille; Johnson, Lauri

    2015-01-01

    This article discusses themes emerging from studies of Black educational activism conducted in London, Toronto, and Detroit. An analysis of narrative data reveals that Black educational activists resist racism and other forms of oppression; act as border crossers and/or boundary spanners as they navigate complex community-based, institutional, and…

  12. Canada and the United States. Perspective. Learning Activity Packet.

    ERIC Educational Resources Information Center

    Maine Univ., Orono. New England - Atlantic Provinces - Quebec Center.

    The similarities and differences of Canada and the United States are explored in this Learning Activity Packet (LAP). Ten learning objectives are given which encourage students to examine: 1) the misconceptions Americans and Canadians have about each other and their ways of life; 2) the effect and influence of French and English exploration and…

  13. Physical Education and Physical Activity: A Historical Perspective

    ERIC Educational Resources Information Center

    Guedes, Claudia

    2007-01-01

    Although many recent studies have shown that the lack of physical activity is one of the major causes of obesity, diabetes, and cardiovascular disease among children and adolescents, few studies have shown the connection between the lack of physical education and the prevalence of a sedentary lifestyle. However, it is clear that physical education…

  14. Organizational Learning from the Perspective of Knowledge Maturing Activities

    ERIC Educational Resources Information Center

    Kaschig, A.; Maier, R.; Sandow, A.; Lazoi, M.; Schmidt, A.; Barnes, S.-A.; Bimrose, J.; Brown, A.; Bradley, C.; Kunzmann, C.; Mazarakis, A.

    2013-01-01

    The level of similarity of knowledge work across occupations and industries allows for the design of supportive information and communication technology (ICT) that can be widely used. In a previous ethnographically informed study, we identified activities that can be supported to increase knowledge maturing, conceptualized as goal-oriented…

  15. The Quest for Photoswitches Activated by Near-Infrared Light: A Theoretical Study of the Photochemistry of BF2 -Coordinated Azo Derivatives.

    PubMed

    Moreno, Miquel; Gelabert, Ricard; Lluch, José M

    2016-09-19

    Recently synthesized BF2 -coordinated azo derivatives have been proposed as photoswitches that operate in the optical window (λ=600-1200 nm) for use in bioimaging applications. Herein, we have theoretically analyzed these compounds and modified some substituents to analyze which properties of the molecule govern its photochemistry. Our results compare rather well with the available experimental data, so our methodology, based on density functional theory (DFT) calculations for the ground electronic state and time-dependent-DFT for the first excited electronic state, is validated. Through systematic modification of different substituents of the parent system, we designed compounds that are predicted to operate fully within the optical window. We also analyzed several molecules for which the cis isomer is the more stable isomer, a quite unusual result for azobenzene derivatives that is a much coveted property for some applications of these photoactive molecules in pharmacology. Our results also provide insight into other properties relevant for photoswitches, such as the thermal stability of the less stable isomer and the magnitude of the gap between the wavelengths of the radiation that activates each isomerization process, which must be as large as possible to improve the yield of each photoisomerization. From a more general perspective, our results may provide a step towards the rational design of new photoswitches that fulfill a set of desired characteristics.

  16. National activities in remote sensing: a Canadian perspective

    NASA Astrophysics Data System (ADS)

    Howe, Bruce

    A brief review of the federal government's role in developing remote sensing activities in Canada over the years is given. The struggle to map a large country, together with an interest in space, brought about the Canadian remote sensing program. In particular, the paper focuses on the role of Energy, Mines and Resources Canada in coordinating research activities by all levels of government in remote sensing, thus fostering the growth of the remote sensing industry in Canada. An overview is given of the expanding remote sensing market. In addition, the paper looks at the present applications of remote sensing to agriculture, forestry and the study of ice caps and fresh water, for example, as well as its use in assessing and preventing environmental disasters. The paper concludes by stressing the importance of remote sensing in meeting the "Challenge of the 90's"—making sustainable development a way of life.

  17. Health Activism Targeting Corporations: A Critical Health Communication Perspective.

    PubMed

    Zoller, Heather M

    2017-02-01

    Health activists and health social movements have transformed medical treatment, promoted public health policies, and extended civil rights for people with illness and disability. This essay explores health activism that targets corporate-generated illness and risk in order to understand the unique communicative challenges involved in this area of contention. Arguing for greater critical engagement with policy, the article integrates policy research with social movements, subpolitics, and issue management literature. Drawing from activist discourse and multidisciplinary research, the article describes how a wide array of groups groups build visibility for corporate health effects, create the potential for networking and collaboration, and politicize health by attributing illness to corporate behaviors. The discussion articulates the implications of this activism for health communication theory, research, and practice.

  18. The June 2009 Perspective on Canadian IYA2009 Activities

    NASA Astrophysics Data System (ADS)

    Hesser, James E.; Bartlett, C.; Breland, K.; Hay, K.; Lane, D.; Lacasse, R.; Lemay, D.; Langill, P.; Percy, J.; Welch, D. L.; Woodsworth, A.

    2009-05-01

    IYA effort in Canada is almost entirely a volunteer one relying heavily upon generous donations of time and effort by hundreds of people. Here we analyze accomplishments to date, and we describe activities to come in the remaining seven months of 2009 and well beyond. Accomplishments include provisions of hundreds of diverse opportunities for many thousands to experience their personal moment of astronomical discovery (their `Galileo Moment') a new planetarium show being presented at four major science centres; original works of music and performance that showcase astronomy in a captivating way for children and adults; an animated video narrated in English, French or Mi'kmaq of an Aboriginal story relating the seasons with circumpolar motions of stars; new educational and outreach materials aimed primarily at youth that are distributed freely at IYA events; theatre events; image exhibits; improved science education materials linked closely to curriculum requirements; and many more. In the months to come, all of the above will continue, but opportunities for new activities and partnerships continue to arise, e.g., Canada's Parks Day (18 July) emphasizes IYA, as do numerous cross-cultural events. We provide examples of the activities planned and/or being pursued for the latter portion of 2009 and beyond. These include issuance of a commemorative coin; delivery of a number of new education materials; prototyping of specific programs with Canadian Aboriginal communities in many provinces with the goal of creating multi-year partnerships to improve educational opportunities in their communities; and many more.

  19. Perspective on OECD activities from a non-member country.

    PubMed

    Alexandrova, Nevena; Atanassov, Atanas

    2006-01-01

    The OECD Blue Book, "Recombinant DNA: Safety Considerations" was published in 1986. The developed principles and concepts on the stepwise and case-by-case approach for risk assessment in the Blue Book have been used as a foundation for building national biosafety frameworks and international instruments for the regulation of the products of modern biotechnology. Twenty years after the Blue Book was published, OECD continues its activities on unique identifier systems, information-sharing, consensus documents for the biology of crops, trees and microorganisms with respect to harmonization of regulatory oversight and those of novel food and feed safety. These activities benefit, without any doubt, the international community at large, including OECD non-member countries. In order to strengthen its position in the international arena and to better respond to the needs of the changing world, OECD would be encouraged to participate in a more active manner in the technology transfer process and co-existence debate, together with continuing the organization's efforts on information-sharing and harmonization in the field of biotechnology and biosafety.

  20. Program Diversity in Higher Education: An Economic Perspective.

    ERIC Educational Resources Information Center

    Dill, David D.; Teixeira, Pedro

    2000-01-01

    Suggests an economic perspective for defining and measuring academic diversity in terms of program innovation, not only in teaching, research, and public service activities, but also in the processes of production and markets served. Such a perspective would also provide valuable theoretical frameworks for exploring important questions of how…

  1. National water-information clearinghouse activities; ground-water perspective

    USGS Publications Warehouse

    Haupt, C.A.; Jensen, R.A.

    1988-01-01

    The US Geological Survey (USGS) has functioned for many years as an informal clearinghouse for water resources information, enabling users to access groundwater information effectively. Water resources clearinghouse activities of the USGS are conducted through several separate computerized water information programs that are involved in the collection, storage, retrieval, and distribution of different types of water information. The following USGS programs perform water information clearinghouse functions and provide the framework for a formalized National Water-Information Clearinghouse: (1) The National Water Data Exchange--a nationwide confederation of more than 300 Federal, State, local, government, academic, and private water-oriented organizations that work together to improve access to water data; (2) the Water Resources Scientific Information Center--acquires, abstracts, and indexes the major water-resources-related literature of the world, and provides this information to the water resources community; (3) the Information Transfer Program--develops innovative approaches to transfer information and technology developed within the USGS to audiences in the public and private sectors; (4) the Hydrologic Information Unit--provides responses to a variety of requests, both technical and lay-oriented, for water resources information , and helps efforts to conduct water resources research; (5) the Water Data Storage and Retrieval System--maintains accessible computerized files of hydrologic data collected nationwide, by the USGS and other governmental agencies, from stream gaging stations, groundwater observation wells, and surface- and groundwater quality sampling sites; (6) the Office of Water Data Coordination--coordinate the water data acquisition activities of all agencies of the Federal Government, and is responsible for the planning, design, and inter-agency coordination of a national water data and information network; and (7) the Water Resources Research

  2. Perspective of surface active agents in baking industry: an overview.

    PubMed

    Ahmad, Asif; Arshad, Nazish; Ahmed, Zaheer; Bhatti, Muhammad Shahbaz; Zahoor, Tahir; Anjum, Nomana; Ahmad, Hajra; Afreen, Asma

    2014-01-01

    Different researchers have previously used surfactants for improving bread qualities and revealed that these compounds result in improving the quality of dough and bread by influencing dough strength, tolerance, uniform crumb cell size, and improve slicing characteristics and gas retention. The objective of this review is to highlight the areas where surfactants are most widely used particularly in the bread industries, their role and mechanism of interaction and their contribution to the quality characteristics of the dough and bread. This review reveals some aspects of surface-active agents regarding its role physiochemical properties of dough that in turn affect the bread characteristics by improving its sensory quality and storage stability.

  3. Modulation of brain activity during action observation: influence of perspective, transitivity and meaningfulness.

    PubMed

    Hétu, Sébastien; Mercier, Catherine; Eugène, Fanny; Michon, Pierre-Emmanuel; Jackson, Philip L

    2011-01-01

    The coupling process between observed and performed actions is thought to be performed by a fronto-parietal perception-action system including regions of the inferior frontal gyrus and the inferior parietal lobule. When investigating the influence of the movements' characteristics on this process, most research on action observation has focused on only one particular variable even though the type of movements we observe can vary on several levels. By manipulating the visual perspective, transitivity and meaningfulness of observed movements in a functional magnetic resonance imaging study we aimed at investigating how the type of movements and the visual perspective can modulate brain activity during action observation in healthy individuals. Importantly, we used an active observation task where participants had to subsequently execute or imagine the observed movements. Our results show that the fronto-parietal regions of the perception action system were mostly recruited during the observation of meaningless actions while visual perspective had little influence on the activity within the perception-action system. Simultaneous investigation of several sources of modulation during active action observation is probably an approach that could lead to a greater ecological comprehension of this important sensorimotor process.

  4. Experimental and Theoretical Reduction Potentials of Some Biologically Active ortho-Carbonyl para-Quinones.

    PubMed

    Martínez-Cifuentes, Maximiliano; Salazar, Ricardo; Ramírez-Rodríguez, Oney; Weiss-López, Boris; Araya-Maturana, Ramiro

    2017-04-04

    The rational design of quinones with specific redox properties is an issue of great interest because of their applications in pharmaceutical and material sciences. In this work, the electrochemical behavior of a series of four p-quinones was studied experimentally and theoretically. The first and second one-electron reduction potentials of the quinones were determined using cyclic voltammetry and correlated with those calculated by density functional theory (DFT) using three different functionals, BHandHLYP, M06-2x and PBE0. The differences among the experimental reduction potentials were explained in terms of structural effects on the stabilities of the formed species. DFT calculations accurately reproduced the first one-electron experimental reduction potentials with R² higher than 0.94. The BHandHLYP functional presented the best fit to the experimental values (R² = 0.957), followed by M06-2x (R² = 0.947) and PBE0 (R² = 0.942).

  5. An Activity-Theoretic Approach to Multi-Touch Tools in Early Mathematics Learning

    ERIC Educational Resources Information Center

    Ladel, Silke; Kortenkamp, Ulrich

    2013-01-01

    In this article we present an activity theory based framework that can capture the complex situations that arise when modern technology like multi-touch devices are introduced in classroom situations. As these devices are able to cover more activities than traditional technologies, even computerbased, media, we have to accept that they now take a…

  6. Collective Digital Storytelling: An Activity-Theoretical Analysis of Second Language Learning and Teaching

    ERIC Educational Resources Information Center

    Kalyaniwala-Thapliyal, Carmenne

    2016-01-01

    This paper describes the collective activity of a group of four students who created a digital story as a teaching resource that was to be used for teaching English as a foreign language. It uncovers and analyzes the actual processes underlining the activity as it unfolds from one stage to another. Four processes, viz., sociocognitive…

  7. Understanding Chemistry Professors' Use of Educational Technologies: An Activity Theoretical Approach

    ERIC Educational Resources Information Center

    Kahveci, Ajda; Gilmer, Penny J.; Southerland, Sherry A.

    2008-01-01

    The aim of this study is to understand the influences on chemistry professors' use of educational technology. For this, we use activity theory to focus on two university chemistry professors and the broader activity system in which they work. We analyse their beliefs and past experiences related to teaching, learning, and technology as well as…

  8. Adolescents' perspectives on the barriers and facilitators of physical activity: a systematic review of qualitative studies.

    PubMed

    Martins, João; Marques, Adilson; Sarmento, Hugo; Carreiro da Costa, Francisco

    2015-10-01

    This article examined qualitative studies of adolescents' perspectives about the facilitators and barriers of physical activity, published from 2007 to 2014. A systematic review of 'Web of Science', 'EBSCO', 'Psychinfo' and 'ERIC' databases was performed according to Preferred Reporting Items for Systematic reviews and Meta-analyses guidelines. The following keywords were used: 'physical activity' and 'physical education', each one individually associated with 'correlate', 'determinant', 'facilitator', 'barrier', 'factor influen*', and with 'qualitative', 'focus group', 'interview', "narrative'. Out of 3815 studies initially identified, due to inclusion and quality criteria, only 12 were fully reviewed. Studies' outcomes were analyzed through thematic analysis. The majority of these reported research with young adolescent girls. Few studies have considered the socioeconomic status influence. According to young people's perspectives, the main facilitators and hampering factors to their participation in physical activity were the following: attitude toward physical activity; motivation; perceptions of competence and body image; fun; influence of friends, family and physical education teachers and environmental physical activity opportunities. Specific life transition periods were referred only as a barrier to physical activity. Strategies of pedagogical actions and for developing physical activity intervention programs were discussed, in order to effectively promote the adoption of active lifestyles among youth.

  9. Physical activity perceptions, context, barriers, and facilitators from a Hispanic child's perspective

    PubMed Central

    Ross, Sharon E. Taverno; Francis, Lori A.

    2016-01-01

    Background In order to develop effective physical activity interventions and to address the burden of obesity in Hispanic children, qualitative studies are needed to build descriptive theory and expand the state of the science. The purpose of this study is to describe physical activity perceptions, context, facilitators, and barriers from the perspective of Hispanic immigrant-origin children. Method This in-depth, ethnographic study included 14, 6- to 11-year old, first- and second- generation Hispanic children recruited from an afterschool program in Southeastern Pennsylvania, USA. Methods included child observation, field notes, semi-structured interviews, and a PhotoVoice activity. Transcripts and field notes were coded and analyzed using the constant comparison method to identify overarching themes and patterns in the data. Results Data analysis yielded four overarching themes regarding children's perspectives on physical activity. Children engaged in a variety of physical activities and sedentary behaviors, which differed by physical (e.g., park, outside home, and afterschool programs) and social (e.g., parents, siblings, and friends) contexts. Children discussed specific benefits of physical activity. Children's negative attitudes toward physical activity were related to physical discomfort, low athletic competence, and safety concerns. Children perceived physical activity and play to be one in the same, and “fun” was identified as a primary driver of physical activity preferences. The facilitators and barriers to physical activity were related to specific parent/home, school, and neighborhood factors. Conclusion Findings from this study suggest that an emphasis on fun and active play, while taking into account family and neighborhood context, may be a desirable intervention approach in Hispanic immigrant-origin children. This study lays the groundwork for future studies to further explore some of the themes identified here to better understand children

  10. Theoretical Reactivity Study of Indol-4-Ones and Their Correlation with Antifungal Activity.

    PubMed

    Zermeño-Macías, María de Los Ángeles; González-Chávez, Marco Martín; Méndez, Francisco; González-Chávez, Rodolfo; Richaud, Arlette

    2017-03-08

    Chemical reactivity descriptors of indol-4-ones obtained via density functional theory (DFT) and hard-soft acid-base (HSAB) principle were calculated to prove their contribution in antifungal activity [...].

  11. Theoretical analysis of the cost of antagonistic activity for aquatic bacteria in oligotrophic environments

    PubMed Central

    Aguirre-von-Wobeser, Eneas; Eguiarte, Luis E.; Souza, Valeria; Soberón-Chávez, Gloria

    2015-01-01

    Many strains of bacteria produce antagonistic substances that restrain the growth of others, and potentially give them a competitive advantage. These substances are commonly released to the surrounding environment, involving metabolic costs in terms of energy and nutrients. The rate at which these molecules need to be produced to maintain a certain amount of them close to the producing cell before they are diluted into the environment has not been explored so far. To understand the potential cost of production of antagonistic substances in water environments, we used two different theoretical approaches. Using a probabilistic model, we determined the rate at which a cell needs to produce individual molecules in order to keep on average a single molecule in its vicinity at all times. For this minimum protection, a cell would need to invest 3.92 × 10−22 kg s−1 of organic matter, which is 9 orders of magnitude lower than the estimated expense for growth. Next, we used a continuous model, based on Fick's laws, to explore the production rate needed to sustain minimum inhibitory concentrations around a cell, which would provide much more protection from competitors. In this scenario, cells would need to invest 1.20 × 10−11 kg s−1, which is 2 orders of magnitude higher than the estimated expense for growth, and thus not sustainable. We hypothesize that the production of antimicrobial compounds by bacteria in aquatic environments lies between these two extremes. PMID:26074891

  12. Trichloramine Removal with Activated Carbon Is Governed by Two Reductive Reactions: A Theoretical Approach with Diffusion-Reaction Models.

    PubMed

    Matsushita, Taku; Matsui, Yoshihiko; Ikekame, Shohei; Sakuma, Miki; Shirasaki, Nobutaka

    2017-04-06

    Mechanisms underlying trichloramine removal with activated carbon treatment were proven by batch experiments and theoretical analysis with diffusion-reaction models. The observed values of trichloramine and free chlorine were explained only by the model in which (1) both trichloramine and free chlorine were involved as reactants, (2) the removals of reactants were affected both by the intraparticle diffusion and by the reaction with activated carbon, and (3) trichloramine decomposition was governed by two distinct reductive reactions. One reductive reaction was expressed as a first-order reaction: the reductive reaction of trichloramine with the basal plane of PAC, which consists of graphene sheets. The other reaction was expressed as a second-order reaction: the reductive reaction of trichloramine with active functional groups located on the edge of the basal plane. Free chlorine competitively reacted with both the basal plane and the active functional groups. The fact that the model prediction succeeded even in experiments with different activated carbon doses, with different initial trichloramine concentrations, and with different sizes of activated carbon particles clearly proved that the mechanisms described in the model were reasonable for explaining trichloramine removal with activated carbon treatment.

  13. A Trans-Theoretical Approach to Physical Activity Profile in General Population of Mashhad.

    PubMed

    Abbasi Shaye, Zahra; Mousavi Bazzaz, Mojtaba; Vakili, Veda

    2015-03-26

    Regular physical-activity is necessity for a healthy lifestyle. Despite public health efforts, a minority of population are involved in healthy levels of physical-activity. This study provides evidence about exercise patterns and predictors of Mashhad-Iran population according to TTM change stages. In this cross-sectional study, we surveyed a total number of 564 participants from Mashhad in 2014 by using stages of change questionnaire. Analysis showed 23.4% of participants were in pre-contemplation stage, 18 in contemplation, 24.6% in preparation, 8.10% in action, 14.4% in maintenance and 11.5% were in termination phase. Age, gender, BMI, alcohol consumption, sleep duration, having compeer and encouragement were identified as predictors of pre-contemplation stage. Genders, having company and using bicycle for transportation were predictors of termination phase. Tailor interventions based on the predictors to enhance the physical activity among specific subgroups would be of interest.

  14. A Trans-Theoretical Approach to Physical Activity Profile in General Population of Mashhad

    PubMed Central

    Shaye, Zahra Abbasi; Bazzaz, Mojtaba Mousavi; Vakili, Veda

    2015-01-01

    Regular physical-activity is necessity for a healthy lifestyle. Despite public health efforts, a minority of population are involved in healthy levels of physical-activity. This study provides evidence about exercise patterns and predictors of Mashhad-Iran population according to TTM change stages. In this cross-sectional study, we surveyed a total number of 564 participants from Mashhad in 2014 by using stages of change questionnaire. Analysis showed 23.4% of participants were in pre-contemplation stage, 18 in contemplation, 24.6% in preparation, 8.10% in action, 14.4% in maintenance and 11.5% were in termination phase. Age, gender, BMI, alcohol consumption, sleep duration, having compeer and encouragement were identified as predictors of pre-contemplation stage. Genders, having company and using bicycle for transportation were predictors of termination phase. Tailor interventions based on the predictors to enhance the physical activity among specific subgroups would be of interest. PMID:26153203

  15. Growth, hyperpolarizability, characterization and theoretical studies of NLO active tris(allylthiourea)mercury(II) chloride

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Single crystals of tris(allylthiourea)mercury(II) chloride (TATMC) have been grown by slow evaporation solution growth technique. It belongs to the trigonal system with noncentrosymmetric space group R3c and the cell parameters are, a = b = 11.4443(3) Å, c = 28.1142(6) Å, V = 3188.85(14) Å3, α = β = 90°, γ = 120° and Z = 6. Powder X-ray diffraction pattern reveals the crystallinity of the as-grown specimen and it closely resembles the simulated one from the single crystal XRD data. Good reflectance in the visible region is observed and the band gap energy is estimated using diffuse reflectance data by the application of Kubelka-Munk algorithm. The functional groups are identified by Fourier transform infrared spectral analysis and compared with theoretical spectrum. The crystal is stable up to the melting point and the mechanistic behavior is ascertained by microhardness studies. The second harmonic generation efficiency of TATMC is estimated by Kurtz and Perry powder technique. The first-order molecular hyperpolarizabilities of some tris(allylthiourea) complexes have been evaluated using density functional theory (DFT) employing B3LYP functional, LanL2DZ as basis set and results rationalized. The optimized geometry closely resembles the ORTEP. The Hirshfeld surface analysis is carried out using HF method with 3-21G as basis set. Investigation of the intermolecular interactions and crystal packing via Hirshfeld surface analysis, derived by single crystal XRD data, reveals the close contacts associated with strong interactions.

  16. Observation of EHO in NSTX and Theoretical Study of its Active Control Using HHFW Antenna

    SciTech Connect

    J.-K. Park, et. al.

    2013-01-14

    Two important topics in the tokamak ELM control, using the non-axisymmetric (3D) magnetic perturbations, are studied in NSTX and combined envisioning ELM control in the future NSTX-U operation: Experimental observations of the edge harmonic oscillation in NSTX (not necessarily the same as EHOs in DIII-D), and theoretical study of its external drive using the high harmonic fast wave (HHFW) antenna as a 3D field coil. Edge harmonic oscillations were observed particularly well in NSTX ELM-free operation with low n core modes, with various diagnostics confirming n = 4 ~ 6 edge-localized and coherent oscillations in 2 ~ 8kHz frequency range. These oscillations seem to have a favored operational window in rotational shear, similarly to EHOs in DIII-D QH modes . However, in NSTX, they are not observed to provide particle or impurity control, possibly due to their weak amplitudes, of a few mm displacements, as measured by reflectometry. The external drive of these modes has been proposed in NSTX, by utilizing audio-frequency currents in the HHFW antenna straps. Analysis shows that the HHFW straps can be optimized to maximize n = 4 ~ 6 while minimizing n = 1 ~ 3. Also, IPEC calculations show that the optimized configuration with only 1kAt current can produce comparable or larger displacements than the observed internal modes. If this optimized external drive can be constructively combined, or further resonated with the internal modes, the edge harmonic oscillations in NSTX may be able to produce sufficient particle control to modify ELMs.

  17. A Theoretical and Empirical Exploration of Intrinsic Problems in Designing Inquiry Activities

    ERIC Educational Resources Information Center

    Meyer, Daniel Z.; Meyer, Allison Antink; Nabb, Keith A.; Connell, Margaretann G.; Avery, Leanne M.

    2013-01-01

    A central concern in science education is promoting inquiry activities, and a significant amount of research in science education has addressed what inhibits this goal. However, this research has tended to be focused on implementation issues. Levels of implementation are correlated with extrinsic barriers such as time, resources and teacher…

  18. Some theoretical priciples of the activation of wood charcoal by steam

    SciTech Connect

    Fedoseev, A.S.

    1982-01-01

    Kinetics and diffusion in the pores of a carbonaceous material are considered. The macroscopic rate of the reaction of steam with the carbon of wood charcoal has been determined. The optimum conditions for the activation of wood charcoal have been found.

  19. Problem Articulation and the Processes of Assistance: An Activity Theoretic View of Mediation in Game Play

    ERIC Educational Resources Information Center

    Stone, Lynda D.; Gutierrez, Kris D.

    2007-01-01

    In this article, we study a local adaptation of the Fifth Dimension [Cole, M. (1996). "Cultural psychology: A once and future discipline." Cambridge: Cambridge University Press] known as Las Redes (i.e., Networks of Collaboration in the Fifth Dimension) to examine how the multiple activity systems of Las Redes, e.g. the undergraduate course and…

  20. A Systematic Ecological Model for Adapting Physical Activities: Theoretical Foundations and Practical Examples

    ERIC Educational Resources Information Center

    Hutzler, Yeshayahu

    2007-01-01

    This article proposes a theory- and practice-based model for adapting physical activities. The ecological frame of reference includes Dynamic and Action System Theory, World Health Organization International Classification of Function and Disability, and Adaptation Theory. A systematic model is presented addressing (a) the task objective, (b) task…

  1. From Traditional to Constructivist Epistemologies: A Proposed Theoretical Framework Based on Activity Theory for Learning Communities

    ERIC Educational Resources Information Center

    Hung, David; Tan, Seng-Chee; Koh, Thiam-Seng

    2006-01-01

    This article is concerned with how learning communities are transformed as they evolve from traditional learning epistemologies towards constructivist orientations and pedagogies. Adopting activity theory as a framework, the article discusses how transformations take place through a two-way process of appropriation (learning from one another as a…

  2. Structure-Thermodynamics-Antioxidant Activity Relationships of Selected Natural Phenolic Acids and Derivatives: An Experimental and Theoretical Evaluation

    PubMed Central

    Zheng, Jie; Liang, Guizhao

    2015-01-01

    Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media. PMID:25803685

  3. Structure-thermodynamics-antioxidant activity relationships of selected natural phenolic acids and derivatives: an experimental and theoretical evaluation.

    PubMed

    Chen, Yuzhen; Xiao, Huizhi; Zheng, Jie; Liang, Guizhao

    2015-01-01

    Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media.

  4. Lateral vibration control of a flexible overcritical rotor via an active gas bearing - Theoretical and experimental comparisons

    NASA Astrophysics Data System (ADS)

    Pierart, Fabian G.; Santos, Ilmar F.

    2016-11-01

    The lack of damping of radial gas bearings leads to high vibration levels of a rotor supported by this type of bearing when crossing resonant areas. This is even more relevant for flexible rotors, as studied in this work. In order to reduce these high vibration levels, an active gas bearing is proposed. The control action of this active bearing is selected based on two different strategies: a simple proportional integral derivative controller and an optimal controller. Both controllers are designed based on a theoretical model previously presented. The dynamics of the flexible rotor are modelled aided by the finite element method and the rotor-fluid interaction in the gas bearing is included using the solution of a modified version of the Reynolds equation for compressible fluids, taking into account the piezoelectrically controlled jet action. Performance and accuracy of both model-based controllers are compared against experimental results, showing good agreement. Theoretical and experimental results show a significant increase in the damping ratio of the system, enabling the flexible rotor to run safely across the critical speeds and up to 12,000 rev/min, i.e. 50 percent over the second critical speed without any instability problems.

  5. Choosing where to work at work - towards a theoretical model of benefits and risks of activity-based flexible offices.

    PubMed

    Wohlers, Christina; Hertel, Guido

    2017-04-01

    Although there is a trend in today's organisations to implement activity-based flexible offices (A-FOs), only a few studies examine consequences of this new office type. Moreover, the underlying mechanisms why A-FOs might lead to different consequences as compared to cellular and open-plan offices are still unclear. This paper introduces a theoretical framework explaining benefits and risks of A-FOs based on theories from work and organisational psychology. After deriving working conditions specific for A-FOs (territoriality, autonomy, privacy, proximity and visibility), differences in working conditions between A-FOs and alternative office types are proposed. Further, we suggest how these differences in working conditions might affect work-related consequences such as well-being, satisfaction, motivation and performance on the individual, the team and the organisational level. Finally, we consider task-related (e.g. task variety), person-related (e.g. personality) and organisational (e.g. leadership) moderators. Based on this model, future research directions as well as practical implications are discussed. Practitioner Summary: Activity-based flexible offices (A-FOs) are popular in today's organisations. This article presents a theoretical model explaining why and when working in an A-FO evokes benefits and risks for individuals, teams and organisations. According to the model, A-FOs are beneficial when management encourages employees to use the environment appropriately and supports teams.

  6. Using behavioural activation in the treatment of depression: a control theory perspective.

    PubMed

    McEvoy, P; Law, A; Bates, R; Hylton, K; Mansell, W

    2013-12-01

    Behavioural activation is an intervention that can be used to counteract the typical patterns of withdrawal, avoidance and inactivity that characterize depression. This paper examines the processes of change that may occur during behavioural activation from the perspective of control theory. Some of the key concepts that are associated with control theory are introduced and the process of change that may occur during behavioural activation is illustrated using two case studies. The case studies provide anecdotal evidence which supports the hypothesis that the effective implementation of behavioural activation may depend upon clients being able to retain or regain the sense of control that they value. The differences between a control-theory-based approach and more orthodox behavioural and cognitive approaches are highlighted and the implications of these differences are discussed. Flexible approaches that are informed by control theory, may offer a useful alternative to the more established behavioural and cognitive approaches towards behavioural activation.

  7. Synthesis, characterization, antimicrobial activity and theoretical studies of new thiophene-based tripodal ligands

    NASA Astrophysics Data System (ADS)

    Harit, Tarik; Bellaouchi, Reda; Asehraou, Abdeslam; Rahal, Mahmoud; Bouabdallah, Ibrahim; Malek, Fouad

    2017-04-01

    The synthesis of new thiophene-tripods with different side arms was reported. These compounds were obtained in good yields and their structures were confirmed by NMR spectroscopy, elemental analysis, infrared spectroscopy and mass spectrometry. The in vitro antibacterial and antifungal activities of these products were screened against Gram positive bacteria (Micrococcus luteus and Bacillus subtilis), Gram negative bacteria (Escherichia coli) and fungi (Candida pelliculosa). The obtained results showed that tripods containing a hydroxyl group in the side arm inhibited both Gram-positive and Gram-negative bacteria, while the tripod with an isopropyl side arm inhibited only the Gram-negative bacteria. DFT calculations with B3LYP/6-31G* level have been used to analyze the electronic and geometric characteristics. The molecular electrostatic potential surface (MEPS) indicated that the presence of electrophile site in the side arm could be responsible for activities against Gram-positive bacteria.

  8. Synthesis, photoluminescent, antibacterial activities and theoretical studies of 4-hydroxycoumarin derivatives

    NASA Astrophysics Data System (ADS)

    Li, Jing; Hou, Zheng; Li, Fen; Zhang, Zi-dan; Zhou, Ying; Luo, Xiao-xing; Li, Ming-kai

    2014-10-01

    Two new biscoumarin and epoxydicoumarin derivatives, namely, 3,3‧-(4-di-p-tolyl-amino-benzylidene)-bis-(4-hydroxycoumarin) (DBH) and 9-(4-di-p-tolyl-amino-phenyl)-1,8-dioxo-9H-dibenzo[c,h]-2,7,10-trioxanthene (DDT), were synthesized and characterized via IR, 1H NMR, HRMS, single crystal X-ray crystallography and UV-vis absorption spectra. The fluorescence behaviors of DBH and DDT in dichloromethane solutions were observed. The in vitro antibacterial activity of DBH and DDT against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC) was evaluated by observing the minimum inhibitory concentration. The results showed that compared with compound DDT, DBH exhibited better potent antibacterial activity.

  9. Dinuclear copper complexes with imidazole derivative ligands: a theoretical study related to catechol oxidase activity.

    PubMed

    Martínez, Ana; Membrillo, Ingrid; Ugalde-Saldívar, Victor M; Gasque, Laura

    2012-07-19

    Catechol oxidase is a very important and interesting metalloprotein. In spite of the efforts to understand the reaction mechanism of this protein, there are important questions that remain unanswered concerning the catalytic mechanism of this enzyme. In this article, dinuclear copper compounds are used as biomimetic models of catechol oxidase to study plausible reaction paths. These dinuclear copper(II) complexes have distant metal centers (of 7.5 Å approximately) and superior catalytic activity to that of many dicopper complexes with shorter Cu-Cu distances. One mononuclear copper(II) complex is also analyzed in this investigation in order to see the influence of the two metal centers in the catalytic activity. Density functional theory calculations were performed to obtain optimized structures, vertical ionization energies, vertical electron affinities, the electrodonating power (ω(-)), the electroaccepting power (ω(+)) and the energy difference of several reaction paths. The K(M) experimental results that were previously reported compare well with the electroaccepting power (ω(+)) of the copper compounds that are included in this article, indicating that this index is useful for the interpretation of the electron transfer capacity and therefore the catalytic activity. The catechol moiety coordinates to only one Cu ion, but two metal atoms are needed in order to have a good electron acceptor capacity of the biomimetic models.

  10. Theoretical analysis on relationship between the neural activity and the EEG.

    PubMed

    Kitazoe, Y; Hiraoka, N; Ueta, H; Ogura, H; Yamamoto, K; Seto, K; Saito, H

    1983-10-21

    Firstly, a collective oscillation mode of the neural activity is derived from the neural network system by using the multicompartment equation and the projection operator technique. This technique takes into account higher order interactions among neurons. The solution of the equation gives a chain structure with an infinite number of circuit loops in which each of them is only composed of four neurons. The obtained eigenvalues are quite similar to the spectrum of frequencies of the EEG. Secondly, the time-dependent behavior of the observed EEG is simulated by starting from the elementary process of action potential trains of neurons, which includes the effect of the collective oscillation mode mentioned above. This gives a comprehensive derivation of the EEG from the neural activity of action potentials. The simulation assumes that information of the action potential trains can be transmitted to the EEG through the intermediate states of the postsynaptic potential trains and the slow waves. The paper reports that a slightly modulated activity of a relatively small amount of neurons can cause a strong influence on the shape of the global EEG and that the calculated results reproduce the characteristic features of the EEG in a rat such as the theta rhythm, the spindle wave and the arousal wave.

  11. Synthesis, crystal structure, spectroscopic properties, antibacterial activity and theoretical studies of a novel difunctional acylhydrazone

    NASA Astrophysics Data System (ADS)

    Jin, Yan-Xian; Zhong, Ai-Guo; Zhang, Yu-jian; Pan, Fu-You

    2011-09-01

    A novel difunctional acylhydrazone has been synthesized by the reaction of 5-methylisoxazole-4-carboyl hydrazine with benzaldehyde and characterized by X-ray crystallography and spectroscopy. The obtained results demonstrate the crystal belongs to triclinic, space group P1¯. Moreover, the spectroscopic properties were evaluated through density functional theory (DFT) and time-dependent density functional theory (TD DFT) calculations. The results reveal that UV-Vis absorption peaks at 194, 217.5 and 290.5 nm are mainly attributed to (p, π) → π ∗, partly (p, π) → π ∗ and partly π → π ∗, and predominantly π → π ∗, respectively, with intraligand charge-transfer transition (ILCT) character. The fluorescence emission peak at 485.96 nm should be assigned to ILCT. In addition, the results of antibacterial activities indicate the title compound has certain modest antibacterial activity as well as the broad-spectrum bacteriostasis, which can be supported by the molecular electrostatic potential (MEP). Therefore, the title compound exhibits both antibacterial activity and photoluminescent property, which has potential applications in many fields such as material science and photodynamic therapy.

  12. Quantitative Structure-Antioxidant Activity Models of Isoflavonoids: A Theoretical Study.

    PubMed

    Castellano, Gloria; Torrens, Francisco

    2015-06-08

    Seventeen isoflavonoids from isoflavone, isoflavanone and isoflavan classes are selected from Dalbergia parviflora. The ChEMBL database is representative from these molecules, most of which result highly drug-like. Binary rules appear risky for the selection of compounds with high antioxidant capacity in complementary xanthine/xanthine oxidase, ORAC, and DPPH model assays. Isoflavonoid structure-activity analysis shows the most important properties (log P, log D, pKa, QED, PSA, NH + OH ≈ HBD, N + O ≈ HBA). Some descriptors (PSA, HBD) are detected as more important than others (size measure Mw, HBA). Linear and nonlinear models of antioxidant potency are obtained. Weak nonlinear relationships appear between log P, etc. and antioxidant activity. The different capacity trends for the three complementary assays are explained. Isoflavonoids potency depends on the chemical form that determines their solubility. Results from isoflavonoids analysis will be useful for activity prediction of new sets of flavones and to design drugs with antioxidant capacity, which will prove beneficial for health with implications for antiageing therapy.

  13. A theoretical view on CrO2+-mediated C-H bond activation in ethane

    NASA Astrophysics Data System (ADS)

    Tong, YongChun; Zhang, XiaoYong; Wang, QingYun; Xu, XinJian; Wang, YongCheng

    2015-06-01

    The gas-phase reaction of C-H bond activation in ethane by CrO2+ has been investigated using density functional theory (DFT) at the UB3LYP/6-311G(2d,p) level. Our results reveal that the activation process is actually a spin-forbidden reaction. The involved crossing point between the doublet and quartet potential energy surfaces (PES) has been discussed by two well-known methods, i.e., intrinsic reaction coordinate (IRC) approach for crossing point (CP) and Harvey's algorithm for minimum energy crossing point (MECP). The obtained single ( P1ISC = 2.48 × 10-3) and double ( P1ISC = 4.95 × 10-3) passes estimated at MECP show that the intersystem crossing (ISC) occurs with a little probability. The C-H bond activation processes should proceed to be endothermic by 73.16 kJ/mol on the doublet surface without any spin change.

  14. Quantitative Structure-Antioxidant Activity Models of Isoflavonoids: A Theoretical Study

    PubMed Central

    Castellano, Gloria; Torrens, Francisco

    2015-01-01

    Seventeen isoflavonoids from isoflavone, isoflavanone and isoflavan classes are selected from Dalbergia parviflora. The ChEMBL database is representative from these molecules, most of which result highly drug-like. Binary rules appear risky for the selection of compounds with high antioxidant capacity in complementary xanthine/xanthine oxidase, ORAC, and DPPH model assays. Isoflavonoid structure-activity analysis shows the most important properties (log P, log D, pKa, QED, PSA, NH + OH ≈ HBD, N + O ≈ HBA). Some descriptors (PSA, HBD) are detected as more important than others (size measure Mw, HBA). Linear and nonlinear models of antioxidant potency are obtained. Weak nonlinear relationships appear between log P, etc. and antioxidant activity. The different capacity trends for the three complementary assays are explained. Isoflavonoids potency depends on the chemical form that determines their solubility. Results from isoflavonoids analysis will be useful for activity prediction of new sets of flavones and to design drugs with antioxidant capacity, which will prove beneficial for health with implications for antiageing therapy. PMID:26062128

  15. Mechanism of Antibacterial Activity via Morphology Change of α-AgVO3: Theoretical and Experimental Insights.

    PubMed

    de Oliveira, Regiane Cristina; de Foggi, Camila Cristina; Teixeira, Mayara Mondego; da Silva, Maya Dayana Penha; Assis, Marcelo; Francisco, Eric Mark; Pimentel, Bruna Natalia Alves da Silva; Pereira, Paula Fabiana Dos Santos; Vergani, Carlos Eduardo; Machado, Ana Lúcia; Andres, Juan; Gracia, Lourdes; Longo, Elson

    2017-04-05

    The electronic configuration, morphology, optical features, and antibacterial activity of metastable α-AgVO3 crystals have been discussed by a conciliation and association of the results acquired by experimental procedures and first-principles calculations. The α-AgVO3 powders were synthesized using a coprecipitation method at 10, 20, and 30 °C. By using a Wulff construction for all relevant low-index surfaces [(100), (010), (001), (110), (011), (101), and (111)], the fine-tuning of the desired morphologies can be achieved by controlling the values of the surface energies, thereby lending a microscopic understanding to the experimental results. The as-synthesized α-AgVO3 crystals display a high antibacterial activity against methicillin-resistant Staphylococcus aureus. The results obtained from the experimental and theoretical techniques allow us to propose a mechanism for understanding the relationship between the morphological changes and antimicrobial performance of α-AgVO3.

  16. Theoretical studies of chemical reactivity of metabolically activated forms of aromatic amines toward DNA.

    PubMed

    Shamovsky, Igor; Ripa, Lena; Blomberg, Niklas; Eriksson, Leif A; Hansen, Peter; Mee, Christine; Tyrchan, Christian; O'Donovan, Mike; Sjö, Peter

    2012-10-15

    The metabolism of aromatic and heteroaromatic amines (ArNH₂) results in nitrenium ions (ArNH⁺) that modify nucleobases of DNA, primarily deoxyguanosine (dG), by forming dG-C8 adducts. The activated amine nitrogen in ArNH⁺ reacts with the C8 of dG, which gives rise to mutations in DNA. For the most mutagenic ArNH₂, including the majority of known genotoxic carcinogens, the stability of ArNH⁺ is of intermediate magnitude. To understand the origin of this observation as well as the specificity of reactions of ArNH⁺ with guanines in DNA, we investigated the chemical reactivity of the metabolically activated forms of ArNH₂, that is, ArNHOH and ArNHOAc, toward 9-methylguanine by DFT calculations. The chemical reactivity of these forms is determined by the rate constants of two consecutive reactions leading to cationic guanine intermediates. The formation of ArNH⁺ accelerates with resonance stabilization of ArNH⁺, whereas the formed ArNH⁺ reacts with guanine derivatives with the constant diffusion-limited rate until the reaction slows down when ArNH⁺ is about 20 kcal/mol more stable than PhNH⁺. At this point, ArNHOH and ArNHOAc show maximum reactivity. The lowest activation energy of the reaction of ArNH⁺ with 9-methylguanine corresponds to the charge-transfer π-stacked transition state (π-TS) that leads to the direct formation of the C8 intermediate. The predicted activation barriers of this reaction match the observed absolute rate constants for a number of ArNH⁺. We demonstrate that the mutagenic potency of ArNH₂ correlates with the rate of formation and the chemical reactivity of the metabolically activated forms toward the C8 atom of dG. On the basis of geometric consideration of the π-TS complex made of genotoxic compounds with long aromatic systems, we propose that precovalent intercalation in DNA is not an essential step in the genotoxicity pathway of ArNH₂. The mechanism-based reasoning suggests rational design strategies to

  17. Phenylpropanoid Glycoside Analogues: Enzymatic Synthesis, Antioxidant Activity and Theoretical Study of Their Free Radical Scavenger Mechanism

    PubMed Central

    López-Munguía, Agustín; Hernández-Romero, Yanet; Pedraza-Chaverri, José; Miranda-Molina, Alfonso; Regla, Ignacio; Martínez, Ana; Castillo, Edmundo

    2011-01-01

    Phenylpropanoid glycosides (PPGs) are natural compounds present in several medicinal plants that have high antioxidant power and diverse biological activities. Because of their low content in plants (less than 5% w/w), several chemical synthetic routes to produce PPGs have been developed, but their synthesis is a time consuming process and the achieved yields are often low. In this study, an alternative and efficient two-step biosynthetic route to obtain natural PPG analogues is reported for the first time. Two galactosides were initially synthesized from vanillyl alcohol and homovanillyl alcohol by a transgalactosylation reaction catalyzed by Kluyveromyces lactis β-galactosidase in saturated lactose solutions with a 30%–35% yield. To synthesize PPGs, the galactoconjugates were esterified with saturated and unsaturated hydroxycinnamic acid derivatives using Candida antarctica Lipase B (CaL-B) as a biocatalyst with 40%–60% yields. The scavenging ability of the phenolic raw materials, intermediates and PPGs was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) method. It was found that the biosynthesized PPGs had higher scavenging abilities when compared to ascorbic acid, the reference compound, while their antioxidant activities were found similar to that of natural PPGs. Moreover, density functional theory (DFT) calculations were used to determine that the PPGs antioxidant mechanism proceeds through a sequential proton loss single electron transfer (SPLET). The enzymatic process reported in this study is an efficient and versatile route to obtain PPGs from different phenylpropanoid acids, sugars and phenolic alcohols. PMID:21674039

  18. Theoretical study of the global F region for June solstice, solar maximum, and low magnetic activity

    SciTech Connect

    Sojka, J.J.; Schunk, R.W.

    1985-06-01

    A time-dependent, three-dimensional, multi-ion model of the ionospheric F region at 120-800 km altitude is presented. Account is taken of field-aligned diffusion, cross-field electrodynamic drifts in equatorial and high latitude regions, interhemispheric flow, thermospheric winds, polar wind escape, energy-dependent chemical reactions and neutral composition changes. Attention is also given to the effects of ion production by solar EUV radiation and auroral precipitation, thermal conduction, diffusion-thermal heat flow, local heating and cooling processes, offsets between the geomagnetic and geographic poles, and bending of field lines near the magnetic equator. The model incorporates all phenomena described by previous models and can be applied to tracing magnetic storm and substorm disturbances from high to low latitudes on a global scale. Sample results are provided for ionospheric features during a June solstice, the solar maximum and in a period of low geomagnetic activity. The model will eventually be used to study coupled ionosphere-thermosphere activity. 49 references.

  19. Theoretical study for heterojunction surface of NEA GaN photocathode dispensed with Cs activation

    NASA Astrophysics Data System (ADS)

    Xia, Sihao; Liu, Lei; Wang, Honggang; Wang, Meishan; Kong, Yike

    2016-09-01

    For the disadvantages of conventional negative electron affinity (NEA) GaN photocathodes activated by Cs or Cs/O, new-type NEA GaN photocathodes with heterojunction surface dispensed with Cs activation are investigated based on first-principle study with density functional theory. Through the growth of an ultrathin n-type GaN cap layer on p-type GaN emission layer, a p-n heterojunction is formed on the surface. According to the calculation results, it is found that Si atoms tend to replace Ga atoms to result in an n-type doped cap layer which contributes to the decreasing of work function. After the growth of n-type GaN cap layer, the atom structure near the p-type emission layer is changed while that away from the surface has no obvious variations. By analyzing the E-Mulliken charge distribution of emission surface with and without cap layer, it is found that the positive charge of Ga and Mg atoms in the emission layer decrease caused by the cap layer, while the negative charge of N atom increases. The conduction band moves downwards after the growth of cap layer. Si atom produces donor levels around the valence band maximum. The absorption coefficient of GaN emission layer decreases and the reflectivity increases caused by n-type GaN cap layer.

  20. Molecular catchers for pharmacologically active substances in wastewaters, a theoretical study

    NASA Astrophysics Data System (ADS)

    Salazar Valencia, P. J.; Pérez Merchancano, S. T.; Paredes, H.; Bolívar Marinez, L. E.

    2016-08-01

    A basic and pressing need in the treatment of residual waste waters for urban and rural centers is the removal of pharmacological active residues from them, these resides are originated in a wide array of domestic, agricultural and industrial sources and can't be removed in the residual waters treatment plants by conventional methods, the result is the incorporation of them into the ecosystem altering the physiology and behavior of living organisms. Among the most active pharmacological substances found in very high concentration in residual waters is paracetamol, an analgesic of very wide excessive use due to its ease of access and low cost [1]. No pharmacological substance is entirely absorbed by the human organism and therefore a wide family of molecular residues is excreted by the urinary tract. In this work we have used the AM1 (Austin Model 1), PM3 (Parametric Method 3) and ZINDO/CI semiempirical methods, from the NDO (Neglect Differential Overlap) family [2] to study and observe the structural, electronic and optical characteristics of paracetamol while immersed in different basic and acidic aqueous environments, either alone or interacting with lignosulphonates. We have previously found that lignosulphonates, a lignin derivatives of wide industrial applications, can be engineered as a binding and flocculant agent and acts as molecular catchers therefore showing the potential to be used as a mean to filter and eliminate molecular residues from the residual waters [3].

  1. Synthesis, crystal structure, biological activity and theoretical calculations of novel isoxazole derivatives.

    PubMed

    Jin, R Y; Sun, X H; Liu, Y F; Long, W; Chen, B; Shen, S Q; Ma, H X

    2016-01-05

    Series of isoxazole derivatives were synthesized by substituted chalcones and 2-chloro-6-fluorobenzene formaldehyde oxime with 1,3-dipolar cycloaddition. The target compounds were determined by melting point, IR, (1)H NMR, elemental analyses and HRMS. The crystal structure of compound 3a was detected by X-ray diffraction and it crystallizes in the triclinic space group p2(1)/c with z=4. The molecular geometry of compound 3a was optimized using density functional theory (DFT/B3LYP) method with the 6-31G+(d,p) basis set in the ground state. From the optimized geometry of the molecule, FT-IR, FT-Raman, HOMO-LUMO and natural bond orbital (NBO) were calculated at B3LYP/6-31G+(d,p) level. Finally, the antifungal activity of the synthetic compounds were evaluated against Pythium solani, Gibberella nicotiancola, Fusarium oxysporium f.sp. niveum and Gibberella saubinetii.

  2. Theoretical study of lanthanide mono cation-mediated C-F bond activation

    NASA Astrophysics Data System (ADS)

    Matsuda, Aya; Mori, Hirotoshi

    2011-02-01

    The potential energy surface corresponding to the reaction of lanthanide mono-cations (Ln +; Ln = Ce-Yb) with CH 3F has been investigated using density functional theory calculations. In the initial step of the C-F activation reaction, Ln + directly coordinates to the F atom of CH 3F, and forms same [Ln⋯F⋯CH 3] + type transition state structures with an accompanying electron-transfer from the Ln + to the F atom. Performing intrinsic reaction coordinate calculations from the transition states, we found that all Ln + reactions can be classified into one of two different reaction mechanisms, "harpoon-like" and "insertion-elimination", which were experimentally proposed by Cohrnel et al. and Konayagi et al., respectively. The two mechanisms have been proposed exclusive to each other. Our results show that both reaction mechanisms are possible in Ln + reaction systems.

  3. Theoretical model of DC electric field formation in the ionosphere stimulated by seismic activity

    NASA Astrophysics Data System (ADS)

    Sorokin, V. M.; Chmyrev, V. M.; Yaschenko, A. K.

    2005-09-01

    Seismic activity is accompanied by emanation of soil gases into the atmosphere. These gases transfer positive and negative charged aerosols. Atmospheric convection of charged aerosols forms external electric current, which works as a source of perturbation in the atmosphere ionosphere electric circuit. It is shown that DC electric field generated in the ionosphere by this current reaches up to 10 mV/m, while the long-term vertical electric field disturbances near the Earth's surface do not exceed 100 V/m. Such a limitation of the near-ground field is caused by the formation of potential barrier for charged particles at the Earth's surface in a process of their transport from soil to atmosphere. This paper presents the method for calculation of the electric field in the atmosphere and the ionosphere generated by given distribution of external electric current in the atmosphere.

  4. Biscoumarin derivatives: Synthesis, crystal structure, theoretical studies and induced apoptosis activity on bladder urothelial cancer cell

    NASA Astrophysics Data System (ADS)

    Xin, Jia-jia; Li, Jing; Zhang, Zi-dan; Hu, Xing-bin; Li, Ming-kai

    2015-03-01

    In this study, five new biscoumarin derivatives (1-5) were synthesized and compound 4 inhibited the proliferation of the bladder urothelial cells (J82 cell line) obviously after 48 h treatment at different concentration (1, 5 and 10 μmol/L), and J82 cells were predominantly induced to apoptotic cell death after compound 4 treatment. Morphologic changes of bladder urothelial cancer cells were also observed under transmission electron microscopy (TEM) after compound 4 treatment. In addition, compound 4 had much less toxicity to human umbilical vein endothelial cells. To explore the possible anti-cancer mechanism of compound 4, two classical intramolecular Osbnd H⋯O hydrogen bonds (HBs) in their structures and the corresponding HB energies were performed with the density functional theory (DFT) [B3LYP/6-31G∗] method. Anti-bladder cancer activity of compound 4 is possible due to the intramolecular weakest HB energies.

  5. Synthesis, crystal structure, biological activity and theoretical calculations of novel isoxazole derivatives

    NASA Astrophysics Data System (ADS)

    Jin, R. Y.; Sun, X. H.; Liu, Y. F.; Long, W.; Chen, B.; Shen, S. Q.; Ma, H. X.

    2016-01-01

    Series of isoxazole derivatives were synthesized by substituted chalcones and 2-chloro-6-fluorobenzene formaldehyde oxime with 1,3-dipolar cycloaddition. The target compounds were determined by melting point, IR, 1H NMR, elemental analyses and HRMS. The crystal structure of compound 3a was detected by X-ray diffraction and it crystallizes in the triclinic space group p2(1)/c with z = 4. The molecular geometry of compound 3a was optimized using density functional theory (DFT/B3LYP) method with the 6-31G+(d,p) basis set in the ground state. From the optimized geometry of the molecule, FT-IR, FT-Raman, HOMO-LUMO and natural bond orbital (NBO) were calculated at B3LYP/6-31G+(d,p) level. Finally, the antifungal activity of the synthetic compounds were evaluated against Pythium solani, Gibberella nicotiancola, Fusarium oxysporium f.sp. niveum and Gibberella saubinetii.

  6. Activity Theory as a Theoretical Framework for Health Self-Quantification: A Systematic Review of Empirical Studies

    PubMed Central

    2016-01-01

    Background Self-quantification (SQ) is a way of working in which, by using tracking tools, people aim to collect, manage, and reflect on personal health data to gain a better understanding of their own body, health behavior, and interaction with the world around them. However, health SQ lacks a formal framework for describing the self-quantifiers’ activities and their contextual components or constructs to pursue these health related goals. Establishing such framework is important because it is the first step to operationalize health SQ fully. This may in turn help to achieve the aims of health professionals and researchers who seek to make or study changes in the self-quantifiers’ health systematically. Objective The aim of this study was to review studies on health SQ in order to answer the following questions: What are the general features of the work and the particular activities that self-quantifiers perform to achieve their health objectives? What constructs of health SQ have been identified in the scientific literature? How have these studies described such constructs? How would it be possible to model these constructs theoretically to characterize the work of health SQ? Methods A systematic review of peer-reviewed literature was conducted. A total of 26 empirical studies were included. The content of these studies was thematically analyzed using Activity Theory as an organizing framework. Results The literature provided varying descriptions of health SQ as data-driven and objective-oriented work mediated by SQ tools. From the literature, we identified two types of SQ work: work on data (ie, data management activities) and work with data (ie, health management activities). Using Activity Theory, these activities could be characterized into 6 constructs: users, tracking tools, health objectives, division of work, community or group setting, and SQ plan and rules. We could not find a reference to any single study that accounted for all these activities and

  7. Exterior optical cloaking and illusions by using active sources: A boundary element perspective

    NASA Astrophysics Data System (ADS)

    Zheng, H. H.; Xiao, J. J.; Lai, Y.; Chan, C. T.

    2010-05-01

    Recently, it was demonstrated that active sources can be used to cloak any objects that lie outside the cloaking devices [F. Guevara Vasquez, G. W. Milton, and D. Onofrei, Phys. Rev. Lett. 103, 073901 (2009)]. Here, we propose that active sources can create illusion effects so that an object outside the cloaking device can be made to look like another object. Invisibility is a special case in which the concealed object is transformed to a volume of air. From a boundary element perspective, we show that active sources can create a nearly “silent” domain which can conceal any objects inside and at the same time make the whole system look like an illusion of our choice outside a virtual boundary. The boundary element method gives the fields and field gradients, which can be related to monopoles and dipoles, on continuous curves which define the boundary of the active devices. Both the cloaking and illusion effects are confirmed by numerical simulations.

  8. Lessons on and from the dihybrid cross: An activity-theoretical study of learning in coteaching

    NASA Astrophysics Data System (ADS)

    Roth, Wolff-Michael; Tobin, Kenneth; Zimmermann, Andrea; Bryant, Natasia; Davis, Charles

    2002-03-01

    During their training, future teachers usually learn the subject matter of science. However, they are largely left on their own when it comes to figuring out how to teach this subject matter, that is, how to find appropriate pedagogical forms. In this article we present a model of collective teaching and learning, which we term coteaching/cogenerative dialoguing, as a way to build deep learning of science concepts while learning about alternative ways to teach the same subject matter. As praxis, coteaching brings about a unity between teaching and learning to teach; cogenerative dialoguing brings about a unity between teaching and researching. Both are potential sites for deep learning. We articulate coteaching/cogenerative dialoguing in terms of activity theory and the associated first-person research methodology that has been developed by critical psychologists as a method of choice for dealing with the theory-praxis gap. Our detailed case study highlights opportunities of learning subject matter and pedagogy by university professors who participate in coteaching/cogenerative dialoguing in an urban high school.

  9. Structure, antibacterial activity and theoretical study of 2-hydroxy-1-naphthaldehyde- N-methylethanesulfonylhydrazone

    NASA Astrophysics Data System (ADS)

    Özbek, Neslihan; Kavak, Gülten; Özcan, Yusuf; İde, Semra; Karacan, Nurcan

    2009-02-01

    2-Hydroxy-1-naphthaldehyde- N-methylethanesulfonylhydrazone was synthesized and its structure was investigated by X-ray diffraction, IR, NMR and mass spectroscopies. It crystallizes in the monoclinic system, space group P21/ c, a = 22.712(4), b = 5.793(4), c = 11.032(2) Å, α = 90.0, β = 102.070(8)°, γ = 90.0°, V = 1419.4(1) Å 3, Z = 4. Spectroscopic assignment and calculations carried out using B3LYP/6-31G∗∗ basis set and crystallographic results indicate the predominance of the phenol-imine tautomeric form. It has strong intramolecular hydrogen bond of type O sbnd H N [with distance donor-acceptor 2.579(4) Å]. The angular disposition of the bonds about the sulfur atom significantly deviates from that of a regular tetrahedron as expected. This deviation can be attributed to the non-bonded interactions involving the S dbnd O bonds and methyl groups in both molecular and crystal structure. Result of conformational analysis was also compared with crystallographic data. Antimicrobial activity of the title compound was screened against E. coli ATCC 11230, P. aeruginosa ATCC 28753 , S. enterititis ATCC 40376 , S. aureus ATCC 25923 and B. cereus RSKK 863.

  10. Theoretical and experimental investigations on the structures of purified clay and acid-activated clay

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Wen, Xiao-Dong; Li, Junfen; Yang, Liming

    2006-07-01

    The purified and acidified montmorillonite clay were characterized by XRD, BET and TPD. These results show that acidified clay is provided with more surface area and acid sites. For NH 3-TPD, molecular NH 3 desorption on purified clay and acidified clay occurs at temperatures with 873 and 1000 K, respectively. It is shown for the existence for strong acid sites. By two reactions of the tetrahydropyranylation of n-propanol and the esterification of cyclo-2-pentene with acetic acid, it is shown that the acidified clay displays better catalytic activity for above two organic reactions. By density-functional theory (DFT) method, we have analyzed the structures of different substituted montmorillonite and the effect sorption behavior of Na + in different montmorillonite models. The result shows that the process of substitution will occur apart from octahedral aluminums. The adsorption of NH 3 on clay surfaces have been investigated using TPD and DFT. This is shown that acid sites locate at round the octahedral aluminums, and substitution of Al 3+ for tetrahedral Si will be favorable to NH 3 adsorption.

  11. Experimental and theoretical studies on methanesulfonic acid 1-methylhydrazide: Antimicrobial activities of its sulfonyl hydrazone derivatives

    NASA Astrophysics Data System (ADS)

    Özbek, Neslihan; Alyar, Saliha; Karacan, Nurcan

    2009-12-01

    Methanesulfonic acid 1-methylhydrazide ( msmh) and its sulfonyl hydrazone derivatives, salicylaldehyde- N-methylmethanesulfonylhydrazone ( salmsmh) and 2-hydroxy-1-naphthaldehyde- N-methylmethanesulfonylhydrazone ( nafmsmh) were synthesized and characterized by using FT-IR, 1H NMR, 13C NMR, LC-MS and elemental analysis. Conformation analysis of msmh based on DFT/B3LYP/6-311G(d) method was performed. 1H and 13C shielding tensors of msmh for the most stable conformer were calculated with GIAO/DFT/B3LYP/6-311++G(2d, 2p) methods in vacuo and various solvents such as DMSO, THF, acetonitrile, methanol and aqueous solution. The harmonic vibrational wavenumbers for the most stable conformer were calculated using at B3LYP/6-311G(d) level. Antimicrobial activity of the compounds was also screened against Gram-positive bacteria ( Staphylococcus aureus ATCC 25923, Bacillus cereus RSKK 863) and Gram-negative bacteria ( Escherichia coli ATCC 11230, Salmonella enterititis ATCC 40376, Pseudomonos aeruginosa ATCC 28753) by both disc diffusion and micro dilution methods.

  12. Theoretical study of the phototoxicity of naproxen and the active form of nabumetone.

    PubMed

    Musa, Klefah A K; Eriksson, Leif A

    2008-10-30

    Density functional theory using the hybrid functional B3LYP has been employed in order to study the mechanisms of photoinduced decomposition of the closely related nonsteroidal anti-inflammatory drugs naproxen (NP) and 6-methoxy-2-naphthylacetic acid (MNAA; the active form of nabumetone). The photochemical properties and computed energies of various species obtained in this study show that both drugs dominate in their deprotonated forms at physiological pH. The deprotonated acids are unable to decarboxylate from their excited singlets; instead, they decarboxylate from their first excited triplet states with high efficiency, overcoming energy barriers less than 3 and 1 kcal/mol for MNAA and NP, respectively. The ultraviolet and visible spectra of the neutral, deprotonated, and decarboxylated moieties of MNAA and NP are more-or-less similar but with higher probabilites (oscillator strength) for the latter. This fact, as well as the higher reactivity of NP, is explained in terms of the electron-donating effect of the additional methyl group present in NP. Singlet oxygen, superoxide radical anion, and corresponding peroxyl radical species are expected to be formed in different steps throughout the proposed photodegradation pathways of both drugs, which give rise to their effects on biomolecules, for example, lipid peroxidation.

  13. Theoretical prediction of thermodynamic activities of liquid Au-Sn-X (X=Bi, Sb, Zn) solder systems

    NASA Astrophysics Data System (ADS)

    Awe, O. E.; Oshakuade, O. M.

    2017-02-01

    Molecular interaction volume model has been theoretically used to predict the thermodynamic activities of tin in Au-Sn-Bi and Au-Sn-Sb and the thermodynamic activity of zinc in Au-Sn-Zn at experimental temperatures 800 K, 873 K and 973 K, respectively. On the premise of agreement between the predicted and experimental values, we predicted the activities of the remaining two components in each of the three systems. This prediction was extended from three cross-sections to five cross-sections, and to temperature range 400-600 K, relevant for applications. Iso-activities were plotted. Results show that addition of tin reduces the tendency for chemical short range order in both Au-Sb and Au-Zn systems, while addition of gold and bismuth, respectively, reduce the tendency for chemical short range order in Sn-Sb and Au-Sn systems. Also, we found that, in the desired high-temperature region for applications, while a combination of chemical order and miscibility of components exist in both Au-Sn-Bi and Au-Sn-Zn systems, only chemical order exist in the Au-Sn-Sb system. Results, further show that increase in temperature reduces the phase separation tendency in Au-Sn-Bi system.

  14. Conformational, spectroscopic and nonlinear optical properties of biologically active N,N-dimethyltryptamine molecule: A theoretical study

    NASA Astrophysics Data System (ADS)

    Öner, Nazmiye; Tamer, Ömer; Avcı, Davut; Atalay, Yusuf

    2014-12-01

    The effective psychoactive properties of N,N-dimethyltryptamine (DMT) known as the near-death molecule have encouraged the imagination of many research disciplines for several decades. Although there is no theoretical study, a number of paper composed by experimental techniques have been reported for DMT molecule. In this study, the molecular modeling of DMT was carried out using B3LYP and HSEh1PBE levels of density functional theory (DFT). Our calculations showed that the energy gap between HOMO and LUMO is low, demonstrating that DMT is a biologically active molecule. Large hyperconjugation interaction energies imply that molecular charge transfer occurs in DMT. Moreover, NLO analysis indicates that DMT can be used an effective NLO material.

  15. Conformational, spectroscopic and nonlinear optical properties of biologically active N,N-dimethyltryptamine molecule: a theoretical study.

    PubMed

    Öner, Nazmiye; Tamer, Ömer; Avcı, Davut; Atalay, Yusuf

    2014-12-10

    The effective psychoactive properties of N,N-dimethyltryptamine (DMT) known as the near-death molecule have encouraged the imagination of many research disciplines for several decades. Although there is no theoretical study, a number of paper composed by experimental techniques have been reported for DMT molecule. In this study, the molecular modeling of DMT was carried out using B3LYP and HSEh1PBE levels of density functional theory (DFT). Our calculations showed that the energy gap between HOMO and LUMO is low, demonstrating that DMT is a biologically active molecule. Large hyperconjugation interaction energies imply that molecular charge transfer occurs in DMT. Moreover, NLO analysis indicates that DMT can be used an effective NLO material.

  16. Synthesis, structural, theoretical studies and biological activities of 3-(arylamino)-2-phenyl-1H-inden-1-one derivative

    NASA Astrophysics Data System (ADS)

    El-Sheshtawy, Hamdy S.; Abou Baker, Ahmed M.

    2014-06-01

    Five derivatives of 2-phenyl-1H-indene-1-one have been prepared and fully characterized. Spectroscopic techniques such as FT-IR, 1H NMR, mass spectrometry, and elemental analysis were used to investigate the chemical structures and physical properties of the prepared compounds. The optimized structures and the distribution of the frontier molecular orbital were obtained using density functional theory (DFT) at B3LYP/6-311++G(d,p) level of theory. Additionally, the UV spectral properties of the indene compounds were corroborated by frontier orbital (HOMO and LUMO) calculations. Intramolecular charge transfer (ICT) peak has been observed in the UV spectra of the compounds and theoretically confirmed by the HOMO and LUMO analysis. The potential use of these compounds as antibacterial agents was investigated. The results show that indene-1-one derivatives have an antibacterial activity for both gram-negative (Pseudomonas aeruginosa) and gram-positive (Methicillin Resistant Staphylococcus aureus) bacteria.

  17. Structure-activity relationship of dihydroxy-4-methylcoumarins as powerful antioxidants: correlation between experimental & theoretical data and synergistic effect.

    PubMed

    Kancheva, Vessela D; Saso, Luciano; Boranova, Petya V; Khan, Abdullah; Saroj, Manju K; Pandey, Mukesh K; Malhotra, Shashwat; Nechev, Jordan Z; Sharma, Sunil K; Prasad, Ashok K; Georgieva, Maya B; Joseph, Carleta; DePass, Anthony L; Rastogi, Ramesh C; Parmar, Virinder S

    2010-09-01

    The chain-breaking antioxidant activities of eight coumarins [7-hydroxy-4-methylcoumarin (1), 5,7-dihydroxy-4-methylcoumarin (2), 6,7-dihydroxy-4-methylcoumarin (3), 6,7-dihydroxycoumarin (4), 7,8-dihydroxy-4-methylcoumarin (5), ethyl 2-(7,8-dihydroxy-4-methylcoumar-3-yl)-acetate (6), 7,8-diacetoxy-4-methylcoumarin (7) and ethyl 2-(7,8-diacetoxy-4-methylcoumar-3-yl)-acetate (8)] during bulk lipid autoxidation at 37 degrees C and 80 degrees C in concentrations of 0.01-1.0 mM and their radical scavenging activities at 25 degrees C using TLC-DPPH test have been studied and compared. It has been found that the o-dihydroxycoumarins 3-6 demonstrated excellent activity as antioxidants and radical scavengers, much better than the m-dihydroxy analogue 2 and the monohydroxycoumarin 1. The substitution at the C-3 position did not have any effect either on the chain-breaking antioxidant activity or on the radical scavenging activity of the 7,8-dihydroxy- and 7,8-diacetoxy-4-methylcoumarins 6 and 8. The comparison with DL-alpha-tocopherol (TOH), caffeic acid (CA) and p-coumaric acid (p-CumA) showed that antioxidant efficiency decreases in the following sequence: TOH>CA>3>4>6>5>2>1=7=8=p-CumA. Theoretical calculations and the "Lipinski's Rule of Five" were used for explaining the structure-activity relationships and pharmacokinetic behavior. A higher TGSO oxidation stability was observed in the presence of equimolar (1:1) binary mixtures of coumarins with TOH (1+TOH, 3+TOH and 5+TOH). However, the synergism (14%) was observed only for the binary mixture of 5 + TOH.

  18. [Metabolically active volumes automatic delineation methodologies in PET imaging: review and perspectives].

    PubMed

    Hatt, M; Boussion, N; Cheze-Le Rest, C; Visvikis, D; Pradier, O

    2012-02-01

    PET imaging is now considered a gold standard tool in clinical oncology, especially for diagnosis purposes. More recent applications such as therapy follow-up or tumor targeting in radiotherapy require a fast, accurate and robust metabolically active tumor volumes delineation on emission images, which cannot be obtained through manual contouring. This clinical need has sprung a large number of methodological developments regarding automatic methods to define tumor volumes on PET images. This paper reviews most of the methodologies that have been recently proposed and discusses their framework and methodological and/or clinical validation. Perspectives regarding the future work to be done are also suggested.

  19. Does reading keep you thin? Leisure activities, cultural tastes, and body weight in comparative perspective

    PubMed Central

    Pampel, Fred C.

    2011-01-01

    While sedentary leisure-time activities such as reading, going to movies, attending cultural events, attending sporting events, watching TV, listening to music, and socializing with friends would seem to contribute to excess weight, a perspective focusing on SES differences in cultural tastes suggests the opposite, that some sedentary activities are associated with lower rather than higher body weight. This study aims to test theories of cultural distinction by examining relationships between leisure-time activities and body weight. Using 2007 data on 17 nations from the International Social Survey Program, the analysis estimates relationships between the body mass index and varied leisure-time activities while controlling for SES, physical activities, and sociodemographic variables. Net of controls for SES and physical activities, participation time in cultural activities is associated with lower rather than higher body weight, particularly in high-income nations. The results suggest that both cultural activities and body weight reflect forms of distinction that separate SES-based lifestyles. PMID:21707664

  20. Promoting physical activity for people with neurological disability: perspectives and experiences of physiotherapists.

    PubMed

    Mulligan, Hilda; Fjellman-Wiklund, Anncristine; Hale, Leigh; Thomas, David; Häger-Ross, Charlotte

    2011-08-01

    Both New Zealand and Sweden have health and disability policies that promote recreational exercise within society for people with disability. Despite these policies, levels of physical activity by people with disability in these countries are low. Physiotherapists are equipped to assist people with disabling conditions into physical activity. This qualitative study explored the perspectives and experiences of physiotherapists in New Zealand and Sweden toward promoting physically active recreation for adults with chronic neurological conditions. Nine physiotherapists who worked with adults with neurological disability in a range of long-term rehabilitation and community (home) health services were interviewed and the data analysed for themes. The physiotherapists described innovative and resourceful expertise to assist patients to be physically active. However, they perceived a lack of support for their work from within the health system and a lack of knowledge of disability issues within the recreational arena, both of which they perceived hindered their promotion of physical activity for people with neurological disability. Physiotherapists feel unable to fully support health and disability policies for the promotion of physically active recreation for people with neurological conditions, because of perceived constraints from within the recreational arena and their own health systems. If these constraints were addressed, then physiotherapists could be better agents to promote physical activity for people with neurological conditions.

  1. Perspectives on Active Video Gaming as a New Frontier in Accessible Physical Activity for Youth With Physical Disabilities

    PubMed Central

    Malone, Laurie A.; Fidopiastis, Cali M.; Padalabalanarayanan, Sangeetha; Thirumalai, Mohanraj; Rimmer, James H.

    2016-01-01

    This perspective article explores the utility of active video gaming as a means of reducing sedentary behavior and increasing physical activity among youth with physical disabilities and limitations in lower extremity function who typically are excluded from mainstream exercise options. Youth with physical disabilities are disproportionately affected by health problems that result from sedentary behavior, lack of physical activity, and low fitness levels. Physical, programmatic, and attitudinal barriers have a synergistic and compounded impact on youths' ability to participate in physical activity. A recent health and wellness task force recommendation from the American Physical Therapy Association's Section on Pediatrics supports analyzing individualized health behaviors and preferences that are designed to improve fitness, physical activity, and participation in pediatric rehabilitation. This recommendation represents an opportunity to explore nontraditional options to maximize effectiveness and sustainability of pediatric rehabilitation techniques for youth with disabilities who could best benefit from customized programming. One new frontier in promoting physical activity and addressing common physical activity barriers for youth with physical disabilities is active video games (AVGs), which have received growing attention as a promising strategy for promoting health and fitness in children with and without disabilities. The purpose of this article is to discuss the potential for AVGs as an accessible option to increase physical activity participation for youth with physical disabilities and limitations in lower extremity function. A conceptual model on the use of AVGs to increase physical activity participation for youth with physical disabilities is introduced, and future research potential is discussed, including a development project for game controller adaptations within the Rehabilitation Engineering Research Center on Interactive Exercise Technologies

  2. Perspectives on Active Video Gaming as a New Frontier in Accessible Physical Activity for Youth With Physical Disabilities.

    PubMed

    Rowland, Jennifer L; Malone, Laurie A; Fidopiastis, Cali M; Padalabalanarayanan, Sangeetha; Thirumalai, Mohanraj; Rimmer, James H

    2016-04-01

    This perspective article explores the utility of active video gaming as a means of reducing sedentary behavior and increasing physical activity among youth with physical disabilities and limitations in lower extremity function who typically are excluded from mainstream exercise options. Youth with physical disabilities are disproportionately affected by health problems that result from sedentary behavior, lack of physical activity, and low fitness levels. Physical, programmatic, and attitudinal barriers have a synergistic and compounded impact on youths' ability to participate in physical activity. A recent health and wellness task force recommendation from the American Physical Therapy Association's Section on Pediatrics supports analyzing individualized health behaviors and preferences that are designed to improve fitness, physical activity, and participation in pediatric rehabilitation. This recommendation represents an opportunity to explore nontraditional options to maximize effectiveness and sustainability of pediatric rehabilitation techniques for youth with disabilities who could best benefit from customized programming. One new frontier in promoting physical activity and addressing common physical activity barriers for youth with physical disabilities is active video games (AVGs), which have received growing attention as a promising strategy for promoting health and fitness in children with and without disabilities. The purpose of this article is to discuss the potential for AVGs as an accessible option to increase physical activity participation for youth with physical disabilities and limitations in lower extremity function. A conceptual model on the use of AVGs to increase physical activity participation for youth with physical disabilities is introduced, and future research potential is discussed, including a development project for game controller adaptations within the Rehabilitation Engineering Research Center on Interactive Exercise Technologies

  3. Multi-Level Discourse Analysis in a Physics Teaching Methods Course from the Psychological Perspective of Activity Theory

    ERIC Educational Resources Information Center

    Vieira, Rodrigo Drumond; Kelly, Gregory J.

    2014-01-01

    In this paper, we present and apply a multi-level method for discourse analysis in science classrooms. This method is based on the structure of human activity (activity, actions, and operations) and it was applied to study a pre-service physics teacher methods course. We argue that such an approach, based on a cultural psychological perspective,…

  4. Perspectives of Constraining and Enabling Factors for Health-Promoting Physical Activity by Adults with Intellectual Disability

    ERIC Educational Resources Information Center

    Temple, Viviene A.; Walkley, Jeff W.

    2007-01-01

    Background: Physical activity influences health in individuals and within populations. This study explored factors perceived as enabling or inhibiting participation in physical activity by adults with intellectual disability from a health promotion perspective. Method: Six focus group interviews were conducted: adults with intellectual disability…

  5. The theoretical study of passive and active optical devices via planewave based transfer (scattering) matrix method and other approaches

    SciTech Connect

    Zhuo, Ye

    2011-01-01

    In this thesis, we theoretically study the electromagnetic wave propagation in several passive and active optical components and devices including 2-D photonic crystals, straight and curved waveguides, organic light emitting diodes (OLEDs), and etc. Several optical designs are also presented like organic photovoltaic (OPV) cells and solar concentrators. The first part of the thesis focuses on theoretical investigation. First, the plane-wave-based transfer (scattering) matrix method (TMM) is briefly described with a short review of photonic crystals and other numerical methods to study them (Chapter 1 and 2). Next TMM, the numerical method itself is investigated in details and developed in advance to deal with more complex optical systems. In chapter 3, TMM is extended in curvilinear coordinates to study curved nanoribbon waveguides. The problem of a curved structure is transformed into an equivalent one of a straight structure with spatially dependent tensors of dielectric constant and magnetic permeability. In chapter 4, a new set of localized basis orbitals are introduced to locally represent electromagnetic field in photonic crystals as alternative to planewave basis. The second part of the thesis focuses on the design of optical devices. First, two examples of TMM applications are given. The first example is the design of metal grating structures as replacements of ITO to enhance the optical absorption in OPV cells (chapter 6). The second one is the design of the same structure as above to enhance the light extraction of OLEDs (chapter 7). Next, two design examples by ray tracing method are given, including applying a microlens array to enhance the light extraction of OLEDs (chapter 5) and an all-angle wide-wavelength design of solar concentrator (chapter 8). In summary, this dissertation has extended TMM which makes it capable of treating complex optical systems. Several optical designs by TMM and ray tracing method are also given as a full complement of this

  6. Theoretical study of γ-hexachlorocyclohexane and β-hexachlorocyclohexane isomers interaction with surface groups of activated carbon model.

    PubMed

    Enriquez-Victorero, Carlos; Hernández-Valdés, Daniel; Montero-Alejo, Ana Lilian; Durimel, Axelle; Gaspard, Sarra; Jáuregui-Haza, Ulises

    2014-06-01

    Activated carbon (AC) is employed in drinking water purification without almost any knowledge about the adsorption mechanism of persistent organic pollutants (POPs) onto it. Hexachlorocyclohexane (HCH) is an organochlorinated contaminant present in water and soils of banana crops production zones of the Caribbean. The most relevant isomers of HCH are γ-HCH and β-HCH, both with great environmental persistence. A theoretical study of the influence of AC surface groups (SGs) on HCH adsorption is done in order to help to understand the process and may lead to improve the AC selection process. A simplified AC model consisting of naphthalene with a functional group was used to assess the influence of SGs over the adsorption process. The Multiple Minima Hypersurface (MMH) methodology was employed to study γ-HCH and β-HCH interactions with different AC SGs (hydroxyl and carboxyl) under different hydration and pH conditions. The results obtained showed that association of HCH with SGs preferentially occurs between the axial protons of HCH and SG's oxygen atom, and the most favorable interactions occurring with charged SGs. An increase in carboxylic SGs content is proposed to enhance HCH adsorption onto AC under neutral pH conditions. Finally, this work presents an inexpensive computer aided methodology for preselecting activated carbon SGs content for the removal of a given compound.

  7. A Cultural Historical Activity Theoretical (CHAT) Framework for Understanding the Construction of Inclusive Education from Turkish Teachers' and Parents' Perspectives

    ERIC Educational Resources Information Center

    Kilinc, Sultan

    2016-01-01

    Inclusive education has become a global movement through the policies of the United Nations Educational, Scientific, and Cultural Organization (e.g., Salamanca Statement). These policies led many developing nations to adopt these policies in their national policy agendas. Turkey has developed inclusive education policies that deal with the…

  8. Older People’s Perspectives on Health, Physical Activity and Nutritional Behaviors

    PubMed Central

    Alizadeh, Leila; Salehi, Leili

    2015-01-01

    Background: Approaches for investigating health-promoting lifestyle generally focus on physical activity and regular diet. To explore the perspectives of Iranian elders regarding health, healthy eating and physical activity (PA) this study was conducted in 2012. Methods: Participants in this qualitative study were selected through purposeful sampling. Ten focus groups were conducted with 60 older adults in 3 elderly centers in Tehran. A moderator’s guideline that consisted of general and specific questions was used. Focus groups were audio recorded, transcribed verbatim and analysis was performed using conventional content analysis. Results: Participants explained their perspectives regarding health, healthy eating and PA in the following 5 categories: meaning of health was represented based on issues such as absence of pain and disorder, complete body wellbeing, staying away from hazards, complete individual satisfaction, experiencing positive events, effective communication, faithfulness and trust in God. The healthy eating category was featured by adequate eating, age balanced diet, refraining from under or over nutrition and sensible consumption of fruits and vegetables. The PA was described - according to the level of performing outdoor activities or household tasks. Expressions about the perceived benefits and barriers of healthy eating and PA were aligned the two remaining categories. Conclusions: Participants have referred to the association between both PA and dietary practices and health. Understanding how older people define physical activity and nutritional behavior and recognition of the most important perceived benefits and barriers that might contribute to have a healthy eating or adequate PA profile could procure insight into the type of interventions that are required to promote healthy lifestyle among Iranian older adults. PMID:26933648

  9. Dutch Primary Schoolchildren’s Perspectives of Activity-Friendly School Playgrounds: A Participatory Study

    PubMed Central

    Caro, Helena Elisabeth (Elsje); Altenburg, Teatske Maria; Dedding, Christine; Chinapaw, Mai Jeanette Maidy

    2016-01-01

    School playgrounds are important physical activity (PA) environments for children, yet only a small number of children reaches the target of 40% of moderate-to-vigorous PA time during recess. The aim of this study was to explore children’s perspectives (i.e., child-identified determinants) of activity-friendly school playgrounds. We conducted participatory research with children as co-researchers, framed as a project to give children the opportunity to discuss their views and ideas about their school playgrounds. At three schools, six children (9–12 years old) met over five to seven group meetings. Data analysis included children’s conclusions obtained during the project and the researcher’s analysis of written reports of all meetings. Children indicated a strong desire for fun and active play, with physical playground characteristics and safety, rules and supervision, peer-interactions, and variation in equipment/games as important determinants. Our results indicate that improving activity-friendliness of playgrounds requires an integrated and multi-faceted approach. It also indicates that children, as primary users, are able to identify barriers for active play that are easily overlooked, unknown or differently perceived by adults. Hence, we believe that structural involvement of children in designing, developing and improving playgrounds may increase children’s’ active play and consequently PA levels during recess. PMID:27231923

  10. Oneiric activity and the analytical process. A semiotic perspective on Willy Baranger's theory of dreams.

    PubMed

    Vinocur-Fischbein, Susana

    2005-10-01

    This author reconsiders, from a semiotic perspective, the theoretical and technical ideas developed by Willy and Madeleine Baranger, especially W. Baranger's views on the function of dreams, the status of oneiric symbols and the further clinical-technical use of dreams in the context of the inter-subjective dynamic field, together with the basic unconscious fantasy that emerges in the analytic situation. She attempts to relate the Barangers' ideas to others arising from Peirce's analytic semiotics that would support a triadic conceptualization of dreams. The need to incorporate a pragmatic view of communication and of the processes of production of sense as contributions to dream metapsychology and interpretation in the case of non-neurotic patients is particularly emphasized. On the basis of the hypothesis of a described series of triads underlying the production and retelling of dreams, the acknowledgment of these produced/told dreams as intentional signs allows the presence of a continuous process of semiosis to be proposed. The author introduces clinical material to illustrate the communicative value of dreams through the textual analysis of the report and accompanying associations of three dreams. Such analysis takes a linguistic pragmatics approach that examines those aspects of meaning not accounted for by a restricted semantic theory.

  11. Two-photon polarization dependent spectroscopy in chirality: a novel experimental-theoretical approach to study optically active systems.

    PubMed

    Hernández, Florencio E; Rizzo, Antonio

    2011-04-18

    Many phenomena, including life itself and its biochemical foundations are fundamentally rooted in chirality. Combinatorial methodologies for catalyst discovery and optimization remain an invaluable tool for gaining access to enantiomerically pure compounds in the development of pharmaceuticals, agrochemicals, and flavors. Some exotic metamaterials exhibiting negative refractive index at optical frequencies are based on chiral structures. Chiroptical activity is commonly quantified in terms of circular dichroism (CD) and optical rotatory dispersion (ORD). However, the linear nature of these effects limits their application in the far and near-UV region in highly absorbing and scattering biological systems. In order to surmount this barrier, in recent years we made important advancements on a novel non linear, low-scatter, long-wavelength CD approach called two-photon absorption circular dichroism (TPACD). Herein we present a descriptive analysis of the optics principles behind the experimental measurement of TPACD, i.e., the double L-scan technique, and its significance using pulsed lasers. We also make an instructive examination and discuss the reliability of our theoretical-computational approach, which uses modern analytical response theory, within a Time-Dependent Density Functional Theory (TD-DFT) approach. In order to illustrate the potential of this novel spectroscopic tool, we first present the experimental and theoretical results obtained in C(2)-symmetric, axially chiral R-(+)-1,1'-bi(2-naphthol), R-BINOL, a molecule studied at the beginning of our investigation in this field. Next, we reveal some preliminary results obtained for (R)-3,3'-diphenyl-2,2'-bi-1-naphthol, R-VANOL, and (R)-2,2'-diphenyl-3,3'-(4-biphenanthrol), R-VAPOL. This family of optically active compounds has been proven to be a suitable model for the structure-property relationship study of TPACD, because its members are highly conjugated yet photo-stable, and easily derivatized at the 5

  12. Physical activity adoption to adherence, lapse, and dropout: a self-determination theory perspective.

    PubMed

    Kinnafick, Florence-Emilie; Thøgersen-Ntoumani, Cecilie; Duda, Joan L

    2014-05-01

    Grounded in Self-Determination Theory, we aimed to explore and identify key motivational processes involved in the transition from a physically inactive to an active lifestyle, and the processes involved in lapse and dropout behavior within a walking program. We implemented a qualitative, longitudinal case study method, using semistructured interviews and theoretical thematic analyses. Fifteen women were interviewed over 10 months and three profiles were generated: (a) nonadherence, (b) lapse/readoption of physical activity, and (c) adherence. Internalization of walking behavior was key to adherence. Satisfaction of the needs for competence and relatedness were central for participation during exercise at the adoption stages, and autonomy was particularly pertinent in facilitating adherence. Those who lapsed and restarted physical activity experienced feelings of autonomy at the point of readoption. Sources of support were driving forces in the adoption and adherence phases.

  13. Theoretical Emission-Line Profiles of Active Galactic Nuclei and the Unified Model. I. The Face-on Torus

    NASA Astrophysics Data System (ADS)

    Quintilio, R.; Viegas, S. M.

    1997-01-01

    Theoretical emission-line profiles are obtained for active galactic nuclei (AGNs) taking into account the presence of an obscuring torus around the central energy source. For the sake of simplicity, the torus is represented by a cylindrical shell characterized by the inner and outer radius and the opening angle. In this paper we discuss the results with angle of sight equal to 0, i.e., for a face-on torus. Different line profiles are obtained following the torus parameters. The line profiles may show more than one peak and bumps, depending on the torus dimensions. The main parameter determining the number of peaks or bumps is the opening angle. Thus, the observed line shape may be a good indicator of the torus characteristics. As an example, the fit to the observed [O III] λ5007 emission line of NGC 4151 is presented. The model reproduces the FWHM and the asymmetrical bumps observed. Partially supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) under Grant 92/4335-9.

  14. A theoretical approach to the photochemical activation of matrix isolated aluminum atoms and their reaction with methane

    SciTech Connect

    Pacheco-Blas, M. A.; Novaro, O. A.; Pacheco-Sanchez, J. H.

    2010-11-07

    The photochemical activation of Al atoms in cryogenic matrices to induce their reaction with methane has been experimentally studied before. Here, a theoretical study of the nonadiabatic transition probabilities for the ground ({sup 2}P:3s{sup 2}3p{sup 1}) and the lowest excited states ({sup 2}S:3s{sup 2}4s{sup 1} and {sup 2}D:3s{sup 2}3d{sup 1}) of an aluminum atom interacting with a methane molecule (CH{sub 4}) was carried out through ab initio Hartree-Fock self-consistent field calculations. This was followed by a multiconfigurational study of the correlation energy obtained by extensive variational and perturbational configuration interaction analyses using the CIPSI program. The {sup 2}D state is readily inserted into a C-H bond, this being a prelude to a sequence of avoided crossings with the initially repulsive (to CH{sub 4}) lower lying states {sup 2}P and {sup 2}S. We then use a direct extension of the Landau-Zener theory to obtain transition probabilities at each avoided crossing, allowing the formation of an HAlCH{sub 3} intermediate that eventually leads to the final pair of products H+AlCH{sub 3} and HAl+CH{sub 3}.

  15. Conformation of epicinchonine and cinchonine in view of their antimalarial activity: x-ray and theoretical studies.

    PubMed

    Kowalik, J T; Lipińska, T; Oleksyn, B J; Sliwiński, J

    1999-01-01

    X-ray structure analysis was carried out for a single crystal of 9-epi-10,11-dihydrocinchonine in the form of free base obtained by stereoselective interconversion of cinchonine via 9-O-tosylcinchonine. An intramolecular hydrogen bond was found between the carbinol hydroxyl group, -O12-H12, and the quinuclidine nitrogen atom, N1, with the parameters: O12...N1=2.688(3)A, O12-H12=0.84(4)A, N1...H12=2.11(4)A and O12-H12...N1=126(3) degrees. Theoretical calculations for isolated molecules of epicinchonine and cinchonine with the use of AM1 semiempirical method and comparative studies of the crystal structures have shown that the conformation of the alkaloid molecules with respect to the C8-C9 bond depends on the absolute configuration at C9. The conformation with respect to the C9-C16 bond depends on the protonation of N1 for threo but not for erythro alkaloids. It was established that the ability to form inter- or intramolecular hydrogen bonds is determined by the energetically preferred conformations of erythro and threo alkaloids, respectively. In most cases the conformations preferred for erythro alkaloids are energetically forbidden for their threo epimers and vice versa. The differences in conformation and capability to form intramolecular hydrogen bonds may explain why their antimalarial activities are incomparable.

  16. On the activation of σ-bonds by electric fields: A Valence Bond perspective

    NASA Astrophysics Data System (ADS)

    Rincón, Luis; Mora, Jose R.; Torres, F. Javier; Almeida, Rafael

    2016-09-01

    The activation of non-polar σ -bonds induced by an electric field is studied from the perspective of the Valence Bond theory. As representative examples we study the dissociation of the H-H and C-H bonds of molecular hydrogen and methane, respectively, under the experience of an homogeneous as well as an heterogeneous field oriented along the bond axis. For all cases, the increase in the electric field have similar effects: (i) the stabilization of the potential energy, (ii) an increment of the equilibrium bond length and (iii) the transition from an homolytic dissociation mechanism to an heterolytic one when the bond is subjected under a strong enough field. These general observations are thoroughly explained using a simple Valence Bond model that involve the increment of the resonance energy between the covalent and the ionic structures, and the curve crossing between the two structures after some field strength.

  17. Fighting the stigma caused by mental disorders: past perspectives, present activities, and future directions

    PubMed Central

    STUART, HEATHER

    2008-01-01

    People who live with mental illnesses are among the most stigmatized groups in society. In 1996, in recognition of the particularly harsh burden caused by the stigma associated with schizophrenia, the WPA initiated a global anti-stigma program, Open-the-Doors. In 2005, a WPA Section on Stigma and Mental Health was created, with a broader mandate to reduce stigma and discrimination caused by mental disabilities in general. In light of these impor-tant developments, and the growing public health interest in stigma reduction, this paper reflects on the past perspectives that have led us to our current position, reviews present activities and accomplishments, and identifies challenges that the Section members will face in their future efforts to reduce the stigma caused by mental disorders. PMID:18836546

  18. Factors Related to Meeting Physical Activity Guidelines in Active College Students: A Social Cognitive Perspective

    ERIC Educational Resources Information Center

    Farren, G. L.; Zhang, T.; Martin, S. B.; Thomas, K. T.

    2017-01-01

    Objective: To examine the relations of sex, exercise self-efficacy, outcome expectations, and social support with meeting physical activity guidelines (PAGs). Participants: Three hundred ninety-six college students participated in this study in the summer 2013. Methods: Students completed online questionnaires that assessed physical activity…

  19. Theoretical geodesy

    NASA Astrophysics Data System (ADS)

    Borkowski, Andrzej; Kosek, Wiesław

    2015-12-01

    The paper presents a summary of research activities concerning theoretical geodesy performed in Poland in the period of 2011-2014. It contains the results of research on new methods of the parameter estimation, a study on robustness properties of the M-estimation, control network and deformation analysis, and geodetic time series analysis. The main achievements in the geodetic parameter estimation involve a new model of the M-estimation with probabilistic models of geodetic observations, a new Shift-Msplit estimation, which allows to estimate a vector of parameter differences and the Shift-Msplit(+) that is a generalisation of Shift-Msplit estimation if the design matrix A of a functional model has not a full column rank. The new algorithms of the coordinates conversion between the Cartesian and geodetic coordinates, both on the rotational and triaxial ellipsoid can be mentioned as a highlights of the research of the last four years. New parameter estimation models developed have been adopted and successfully applied to the control network and deformation analysis. New algorithms based on the wavelet, Fourier and Hilbert transforms were applied to find time-frequency characteristics of geodetic and geophysical time series as well as time-frequency relations between them. Statistical properties of these time series are also presented using different statistical tests as well as 2nd, 3rd and 4th moments about the mean. The new forecasts methods are presented which enable prediction of the considered time series in different frequency bands.

  20. Active load management with advanced window wall systems: Research and industry perspectives

    SciTech Connect

    Lee, Eleanor S.; Selkowitz, Stephen E.; Levi, Mark S.; Blanc, Steven L.; McConahey, Erin; McClintock, Maurya; Hakkarainen, Pekka; Sbar, Neil L.; Myser, Michael P.

    2002-06-01

    Advanced window wall systems have the potential to provide demand response by reducing peak electric loads by 20-30% in many commercial buildings through the active control of motorized shading systems, switchable window coatings, operable windows, and ventilated double-skin facade systems. These window strategies involve balancing daylighting and solar heat gains, heat rejection through ventilation, and night-time natural ventilation to achieve space-conditioning and lighting energy use reductions without the negative impacts on occupants associated with other demand responsive (DR) strategies. This paper explores conceptually how advanced window systems fit into the context of active load management programs, which cause customers to directly experience the time-varying costs of their consumption decisions. Technological options are suggested. We present pragmatic criteria that building owners use to determine whether to deploy such strategies. A utility's perspective is given. Industry also provides their perspectives on where the technology is today and what needs to happen to implement such strategies more broadly in the US. While there is significant potential for these advanced window concepts, widespread deployment is unlikely to occur with business-as-usual practice. Technologically, integrated window-lighting-HVAC products are underdeveloped. Implementation is hindered by fragmented labor practices, non-standard communication protocols, and lack of technical expertise. Design tools and information products that quantify energy performance, occupant impacts, reliability, and other pragmatic concerns are not available. Interest within the building industry in sustainability, energy-efficiency, and increased occupant amenity, comfort, and productivity will be the driving factors for these advanced facades in the near term--at least until the dust settles on the deregulated electricity market.

  1. “Fair Play”: A Videogame Designed to Address Implicit Race Bias Through Active Perspective Taking

    PubMed Central

    Kaatz, Anna; Chu, Sarah; Ramirez, Dennis; Samson-Samuel, Clem; Carnes, Molly

    2014-01-01

    Abstract Objective: Having diverse faculty in academic health centers will help diversify the healthcare workforce and reduce health disparities. Implicit race bias is one factor that contributes to the underrepresentation of Black faculty. We designed the videogame “Fair Play” in which players assume the role of a Black graduate student named Jamal Davis. As Jamal, players experience subtle race bias while completing “quests” to obtain a science degree. We hypothesized that participants randomly assigned to play the game would have greater empathy for Jamal and lower implicit race bias than participants randomized to read narrative text describing Jamal's experience. Materials and Methods: University of Wisconsin–Madison graduate students were recruited via e-mail and randomly assigned to play “Fair Play” or read narrative text through an online link. Upon completion, participants took an Implicit Association Test to measure implicit bias and answered survey questions assessing empathy toward Jamal and awareness of bias. Results: As hypothesized, gameplayers showed the least implicit bias but only when they also showed high empathy for Jamal (P=0.013). Gameplayers did not show greater empathy than text readers, and women in the text condition reported the greatest empathy for Jamal (P=0.008). However, high empathy only predicted lower levels of implicit bias among those who actively took Jamal's perspective through gameplay (P=0.014). Conclusions: A videogame in which players experience subtle race bias as a Black graduate student has the potential to reduce implicit bias, possibly because of a game's ability to foster empathy through active perspective taking. PMID:26192644

  2. School District Administrators' Perspectives on the Professional Activities and Influence of Special Educators in Norway and Sweden

    ERIC Educational Resources Information Center

    Cameron, David Lansing; Lindqvist, Gunilla

    2014-01-01

    The purpose of this study is to investigate school district administrators' perspectives concerning the professional activities and influence of special educators in Norway (n?=?266) and Sweden (n?=?290). We examine three themes drawn from a survey of practices and policies in each country: (a) the organisational arrangements in which special…

  3. Experience, Intersubjectivity, and Reflection: A Human Science Perspective on Preparation of Future Professionals in Adaptive Physical Activity

    ERIC Educational Resources Information Center

    Standal, Øyvind F.; Rugseth, Gro

    2016-01-01

    The aim of this article is to show that and how philosophy and philosophical thinking can be of relevance for the preparation of future professionals in adaptive physical activity. To this end we utilize philosophical insights from the human science perspective on two central issues, namely experience and intersubjectivity, which are weaved…

  4. The Importance of Motor Functional Levels from the Activity Limitation Perspective of ICF in Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Mutlu, Akmer

    2010-01-01

    Our purpose in this study was to evaluate performance and capacity as defined by Gross Motor Function Classification System (GMFCS) and Manual Ability Classification System (MACS) from the "activity limitation" perspective of International Classification of Functioning, Disability, and Health (ICF) and to investigate the relationship between the…

  5. Successful After-School Physical Activity Clubs in Urban High Schools: Perspectives of Adult Leaders and Student Participants

    ERIC Educational Resources Information Center

    Garn, Alex C.; McCaughtry, Nate; Kulik, Noel L.; Kaseta, Michele; Maljak, Kim; Whalen, Laurel; Shen, Bo; Martin, Jeffrey J.; Fahlman, Mariane

    2014-01-01

    Grounded in social cognitive theory, the purpose of this study was to examine leaders' and students' perspectives of factors that contribute to effective voluntary after-school physical activity clubs. Data were collected over two-years via field observations (n= 115) and interviews with students (n= 278) and adult leaders (n= 126). Results…

  6. Theoretical study of chlordecone and surface groups interaction in an activated carbon model under acidic and neutral conditions.

    PubMed

    Gamboa-Carballo, Juan José; Melchor-Rodríguez, Kenia; Hernández-Valdés, Daniel; Enriquez-Victorero, Carlos; Montero-Alejo, Ana Lilian; Gaspard, Sarra; Jáuregui-Haza, Ulises Javier

    2016-04-01

    Activated carbons (ACs) are widely used in the purification of drinking water without almost any knowledge about the adsorption mechanisms of the persistent organic pollutants. Chlordecone (CLD, Kepone) is an organochlorinated synthetic compound that has been used mainly as agricultural insecticide. CLD has been identified and listed as a persistent organic pollutant by the Stockholm Convention. The selection of the best suited AC for this type of contaminants is mainly an empirical and costly process. A theoretical study of the influence of AC surface groups (SGs) on CLD adsorption is done in order to help understanding the process. This may provide a first selection criteria for the preparation of AC with suitable surface properties. A model of AC consisting of a seven membered ring graphene sheet (coronene) with a functional group on the edge was used to evaluate the influence of the SGs over the adsorption. Multiple Minima Hypersurface methodology (MMH) coupled with PM7 semiempirical Hamiltonian was employed in order to study the interactions of the chlordecone with SGs (hydroxyl and carboxyl) at acidic and neutral pH and different hydration conditions. Selected structures were re-optimized using CAM-B3LYP to achieve a well-defined electron density to characterize the interactions by the Quantum Theory of Atoms in Molecules approach. The deprotonated form of surface carboxyl and hydroxyl groups of AC models show the strongest interactions, suggesting a chemical adsorption. An increase in carboxylic SGs content is proposed to enhance CLD adsorption onto AC at neutral pH conditions.

  7. Why is "blindsight" blind? A new perspective on primary visual cortex, recurrent activity and visual awareness.

    PubMed

    Silvanto, Juha

    2015-03-01

    The neuropsychological phenomenon of blindsight has been taken to suggest that the primary visual cortex (V1) plays a unique role in visual awareness, and that extrastriate activation needs to be fed back to V1 in order for the content of that activation to be consciously perceived. The aim of this review is to evaluate this theoretical framework and to revisit its key tenets. Firstly, is blindsight truly a dissociation of awareness and visual detection? Secondly, is there sufficient evidence to rule out the possibility that the loss of awareness resulting from a V1 lesion simply reflects reduced extrastriate responsiveness, rather than a unique role of V1 in conscious experience? Evaluation of these arguments and the empirical evidence leads to the conclusion that the loss of phenomenal awareness in blindsight may not be due to feedback activity in V1 being the hallmark awareness. On the basis of existing literature, an alternative explanation of blindsight is proposed. In this view, visual awareness is a "global" cognitive function as its hallmark is the availability of information to a large number of perceptual and cognitive systems; this requires inter-areal long-range synchronous oscillatory activity. For these oscillations to arise, a specific temporal profile of neuronal activity is required, which is established through recurrent feedback activity involving V1 and the extrastriate cortex. When V1 is lesioned, the loss of recurrent activity prevents inter-areal networks on the basis of oscillatory activity. However, as limited amount of input can reach extrastriate cortex and some extrastriate neuronal selectivity is preserved, computations involving comparison of neural firing rates within a cortical area remain possible. This enables "local" read-out from specific brain regions, allowing for the detection and discrimination of basic visual attributes. Thus blindsight is blind due to lack of "global" long-range synchrony, and it functions via "local

  8. Brain activation while thinking about the self from another person's perspective after traumatic brain injury in adolescents.

    PubMed

    Newsome, Mary R; Scheibel, Randall S; Hanten, Gerri; Chu, Z; Steinberg, Joel L; Hunter, Jill V; Lu, Hanzhang; Vasquez, Ana C; Li, Xiaoqi; Lin, Xiaodi; Cook, Lori; Levin, Harvey S

    2010-03-01

    Deficits in self awareness and taking the perspective of others are often observed following traumatic brain injury (TBI). Nine adolescents (ages 12-19 years) who had sustained moderate to severe TBI after an average interval of 2.6 years and nine typically developing (TD) adolescents underwent functional MRI (fMRI) while performing a perspective taking task (D'Argembeau et al., 2007). Participants made trait attributions either from their own perspective or from that of the significant other. The groups did not differ in reaction time or on a consistency criterion. When thinking of the self from a third-person perspective, adolescents with TBI demonstrated greater activation in posterior brain regions implicated in social cognition, the left lingual gyrus (BA 18) and posterior cingulate (BA 31), extending into neighboring regions not generally associated with social cognition, that is, cuneus (BA 31) and parahippocampal gyrus, relative to TD adolescents. We postulate that adolescents with moderate to severe TBI recruited alternative neural pathways during perspective-taking because traumatic axonal injury disrupted their fronto-parietal networks mediating social cognition.

  9. Unexpected Levels of Biological Activity during the Polar Night Offer New Perspectives on a Warming Arctic.

    PubMed

    Berge, Jørgen; Daase, Malin; Renaud, Paul E; Ambrose, William G; Darnis, Gerald; Last, Kim S; Leu, Eva; Cohen, Jonathan H; Johnsen, Geir; Moline, Mark A; Cottier, Finlo; Varpe, Øystein; Shunatova, Natalia; Bałazy, Piotr; Morata, Nathalie; Massabuau, Jean-Charles; Falk-Petersen, Stig; Kosobokova, Ksenia; Hoppe, Clara J M; Węsławski, Jan Marcin; Kukliński, Piotr; Legeżyńska, Joanna; Nikishina, Daria; Cusa, Marine; Kędra, Monika; Włodarska-Kowalczuk, Maria; Vogedes, Daniel; Camus, Lionel; Tran, Damien; Michaud, Emma; Gabrielsen, Tove M; Granovitch, Andrei; Gonchar, Anya; Krapp, Rupert; Callesen, Trine A

    2015-10-05

    The current understanding of Arctic ecosystems is deeply rooted in the classical view of a bottom-up controlled system with strong physical forcing and seasonality in primary-production regimes. Consequently, the Arctic polar night is commonly disregarded as a time of year when biological activities are reduced to a minimum due to a reduced food supply. Here, based upon a multidisciplinary ecosystem-scale study from the polar night at 79°N, we present an entirely different view. Instead of an ecosystem that has entered a resting state, we document a system with high activity levels and biological interactions across most trophic levels. In some habitats, biological diversity and presence of juvenile stages were elevated in winter months compared to the more productive and sunlit periods. Ultimately, our results suggest a different perspective regarding ecosystem function that will be of importance for future environmental management and decision making, especially at a time when Arctic regions are experiencing accelerated environmental change [1].

  10. The ErbB Kinase Domain: Structural Perspectives into Kinase Activation and Inhibition

    PubMed Central

    Bose, Ron; Zhang, Xuewu

    2009-01-01

    Epidermal growth factor receptor (EGFR) and its family members, ErbB2, ErB3 and ErB4, are receptor tyrosine kinases which send signals into the cell to regulate many critical processes including development, tissue homeostasis, and tumorigenesis. Central to the signaling of these receptors is their intracellular kinase domain, which is activated by ligand-induced dimerization of the receptor and phosphorylates several tyrosine residues in the C-terminal tail. The phosphorylated tail then recruits other signaling molecules and relays the signal to downstream pathways. A model of the autoinhibition, activation and feedback inhibition mechanisms for the ErbB kinase domain has emerged from a number of recent structural studies. Meanwhile, recent clinical studies have revealed the relationship between specific ErbB kinase mutations and the responsiveness to kinase inhibitor drugs. We will review these regulation mechanisms of the ErbB kinase domain, and discuss the binding specificity of kinase inhibitors and the effects of kinase domain mutations found in cancer patients from a structural perspective. PMID:18761339

  11. Distinguishing Between Activated and Non-Activated Eosinophils Using a Microelectrode: Theoretical Investigations of Bulk and Surface Polaritons in Magnetic Multilayers

    NASA Astrophysics Data System (ADS)

    Lacy, Fred

    In Part I of this dissertation, a whole cell biosensor which can detect the activation state of eosinophils (one of several types of white blood cells) will be developed and tested. This biosensor, which consists of a small gold electrode (50 μm x 50 μm) and a large gold electrode (1.5 cm x 0.5 cm) on a glass substrate, has been fabricated by photolithographic techniques. The eosinophils are known to exhibit different physical properties when they change from the activated state to the non-activated state. Based on some of these property changes, there should be a corresponding change in the measured electrical impedance. In this research, this biosensor will measure the electrical impedance of the eosinophils. This will show that the biosensor can detect the different states of the eosinophils (through the electrical impedance technique). And from these measurements, the different parameters associated with the electrical impedance can be determined. In Part II of this dissertation, a theoretical calculation will be performed in which bulk and surface magnetic polaritons in magnetic materials will be found. A polariton is the coupling of electromagnetic radiation and the elementary excitation of the given material (in our case, a magnetic material). The structure that we will be considering is a periodic semi-infinite material consisting of alternating antiferromagnetic and nonmagnetic layers. An antiferromagnetic material is a material in which individual atoms exhibit magnetic moments, but the overall magnetization of the material is zero because the moments of every other atom are antiparallel. We will use a method known as the transfer matrix technique to find an expression for the dispersion relation of the bulk and surface waves in these materials. Then we will create plots of omega(k) as we vary the geometric configurations of the layers which make-up the magnetic multilayer. We also will calculate the effect of an external magnetic field on these

  12. The Blackholic energy: long and short Gamma-Ray Bursts (New perspectives in physics and astrophysics from the theoretical understanding of Gamma-Ray Bursts, II)

    NASA Astrophysics Data System (ADS)

    Ruffini, Remo; Bernardini, Maria Grazia; Bianco, Carlo Luciano; Chardonnet, Pascal; Fraschetti, Federico; Gurzadyan, Vahe; Vitagliano, Luca; Xue, She-Sheng

    2005-08-01

    We outline the confluence of three novel theoretical fields in our modeling of Gamma-Ray Bursts (GRBs): 1) the ultrarelativistic regime of a shock front expanding with a Lorentz gamma factor ~ 300; 2) the quantum vacuum polarization process leading to an electron-positron plasma originating the shock front; and 3) the general relativistic process of energy extraction from a black hole originating the vacuum polarization process. There are two different classes of GRBs: the long GRBs and the short GRBs. We here address the issue of the long GRBs. The theoretical understanding of the long GRBs has led to the detailed description of their luminosities in fixed energy bands, of their spectral features and made also possible to probe the astrophysical scenario in which they originate. We are specially interested, in this report, to a subclass of long GRBs which appear to be accompanied by a supernova explosion. We are considering two specific examples: GRB980425/SN1998bw and GRB030329/SN2003dh. While these supernovae appear to have a standard energetics of 1049 ergs, the GRBs are highly variable and can have energetics 104 - 105 times larger than the ones of the supernovae. Moreover, many long GRBs occurs without the presence of a supernova. It is concluded that in no way a GRB can originate from a supernova. The precise theoretical understanding of the GRB luminosity we present evidence, in both these systems, the existence of an independent component in the X-ray emission, usually interpreted in the current literature as part of the GRB afterglow. This component has been observed by Chandra and XMM to have a strong decay on scale of months. We have named here these two sources respectively URCA-1 and URCA-2, in honor of the work that George Gamow and Mario Shoenberg did in 1939 in this town of Urca identifying the basic mechanism, the Urca processes, leading to the process of gravitational collapse and the formation of a neutron star and a supernova. The further

  13. Theoretical and practical considerations for the design of the iMUSH active-source seismic experiment

    NASA Astrophysics Data System (ADS)

    Kiser, E.; Levander, A.; Harder, S. H.; Abers, G. A.; Creager, K. C.; Vidale, J. E.; Moran, S. C.; Malone, S. D.

    2013-12-01

    The multi-disciplinary imaging of Magma Under St. Helens (iMUSH) experiment seeks to understand the details of the magmatic system that feeds Mount St. Helens using active- and passive-source seismic, magnetotelluric, and petrologic data. The active-source seismic component of this experiment will take place in the summer of 2014 utilizing all of the 2600 PASSCAL 'Texan' Reftek instruments which will record twenty-four 1000-2000 lb shots distributed around the Mount St. Helens region. The instruments will be deployed as two consecutive refraction profiles centered on the volcano, and a series of areal arrays. The actual number of areal arrays, as well as their locations, will depend strongly on the length of the experiment (3-4 weeks), the number of instrument deployers (50-60), and the time it will take per deployment given the available road network. The current work shows how we are balancing these practical considerations against theoretical experiment designs in order to achieve the proposed scientific goals with the available resources. One of the main goals of the active-source seismic experiment is to image the magmatic system down to the Moho (35-40 km). Calculating sensitivity kernels for multiple shot/receiver offsets shows that direct P waves should be sensitive to Moho depths at offsets of 150 km, and therefore this will likely be the length of the refraction profiles. Another primary objective of the experiment is to estimate the locations and volumes of different magma accumulation zones beneath the volcano using the areal arrays. With this in mind, the optimal locations of these arrays, as well as their associated shots, are estimated using an eigenvalue analysis of the approximate Hessian for each possible experiment design. This analysis seeks to minimize the number of small eigenvalues of the approximate Hessian that would amplify the propagation of data noise into regions of interest in the model space, such as the likely locations of magma

  14. Cyber Dating Abuse Victimization Among Secondary School Students From a Lifestyle-Routine Activities Theory Perspective.

    PubMed

    Van Ouytsel, Joris; Ponnet, Koen; Walrave, Michel

    2016-02-12

    Controlling one's romantic partner through digital media is a form of cyber dating abuse. To design effective educational campaigns, a deeper understanding of how some young people become victim of this type of abuse within their romantic relationships is warranted. This study is the first to adopt a lifestyle-routine activities theory perspective toward online romantic partner monitoring, by looking at whether secondary school students' risky digital lifestyle and their digital media use are linked to a higher chance of being controlled by a romantic partner, taking into account gender, age, and the length of the romantic relationship. The data of 466 secondary school students (71.0% girls, n = 331) between 16 and 22 years old (M = 17.99 years; SD = 0.92) who were in a romantic relationship are analyzed. Linear regression analysis suggests that engagement in online risk behavior, the length of the romantic relationship, engagement in sexting with the romantic partner, and the amount of social networking site use were significantly linked to victimization of digital controlling behavior. The results are important to practitioners, as they indicate that messages about safe Internet use should be incorporated in prevention and educational campaigns with regard to cyber dating abuse. Suggestions for future research are discussed.

  15. Parenthood and factors that influence outdoor recreational physical activity from a gender perspective

    PubMed Central

    2011-01-01

    Background A physically active life promotes both physical and mental health, increasing well-being and quality of life. Physical activity (PA) performed outdoors has been found to be particularly good for promoting well-being. However, participation in PA can change during the course of a lifetime. Parenthood has been found to be a life event associated with decreased PA, especially among women, although studies in the field are sparse. The aim of this study was to investigate participation in outdoor recreational PA, and factors influencing participation among parents-to-be, with and without previous children, from a gender perspective. Methods This study included baseline data from parents-to-be, 224 women and 208 men, from the municipality of Karlskrona in south-east Sweden. Data collection was carried out during 2008-2009. We measured the self-reported amount of outdoor recreational PA undertaken during the last year and analysed the probability of participating in this PA using 25 variables covering individual and socioeconomic factors. Results Seventy-six per cent of the women and 65% of the men had participated in outdoor recreational PA, varying from several times per month to every day, over a 12-month period prior to one month before pregnancy. Participation in PA indoors and owning a dog or a horse emerged as the most important factors associated with the probability of participation in outdoor recreational PA. Men were affected by a greater number of factors than women, for example men who had a family situation that permitted outdoor recreational PA participated in activities to a greater extent than men without such a family situation. The physical aspect, i.e. improved physical condition, staying power and vigour, also played a significant role with regard to participation among men. Conclusions Becoming a parent is a life-changing event that affects participation in PA. By offering family-oriented PA choices that involve both parents and children

  16. THE SCIENCE OF SCIENCE (NAUKOZNAWSTWO) IN POLAND: THE CHANGING THEORETICAL PERSPECTIVES AND POLITICAL CONTEXTS--A HISTORICAL SKETCH FROM THE 1910S TO 1993.

    PubMed

    Kokowski, Michał

    2015-01-01

    The article sketches the history of naukoznawstwo (literally meaning the science connoisseurship or the science of science or science studies) in Poland from the 1910s to the end of the Cold War (1991), and the recovery of full political independence in 1993. It outlines the changing research perspectives of this interdisciplinary field of knowledge in Poland against a background of changing political conditions caused by the reconfigurations of the political order. The first part of the article concerns the period from the 1910s, when Poland was occupied by Russia, Prussia, and Austria, through the regaining of independence by Poland in 1918, the reconstruction of the state in 1918-1939; the second part--World War II; the third part--the period from the initial period of Soviet dominance (1944-1954) in Poland and simultaneously the beginnings of the Cold War (1947-1954), the period 1955-1956 (when the Polish state was liberated from Sovietization), through the different political crises in October 1956, March 1968, December 1970, and June 1976, to the emergence of the Independent Self-governing Trade Union Solidarity in September 1980, the end of the Cold War (1991), and the recovery of full political independence in 1993. The article outlines the fundamental achievements of prominent Polish scholars (among others K. Twardowski, M. Ossowska, S. Ossowski, T. Kotarbiński, K. Ajdukiewicz, S. Michalski, F. Znaniecki, B. Suchodolski, L. Fleck, M. Choynowski, Z. Modzelewski, S. Amsterdamski), politicians (among others B. Bierut, E. Krasowska), politicians and scholars (H. Jabłoński, S. Kulczyński), as well as committees (among others the Academic Section of the Józef Mianowski Fund, The Science of Science Committee of the Polish Academy of Sciences), schools of thought (among others the Lvov-Warsaw School of Philosophy), and academic units (among others the Science of Science Seminar in Kraków, the Department for the History of Science and Technology of the Polish

  17. The dynamic opponent relativity model: an integration and extension of capacity theory and existing theoretical perspectives on the neuropsychology of arousal and emotion.

    PubMed

    Comer, Clinton S; Harrison, Patti Kelly; Harrison, David W

    2015-01-01

    Arousal theory as discussed within the present paper refers to those mechanisms and neural systems involved in central nervous system activation and more specifically the systems involved in cortical activation. Historical progress in the evolution of arousal theory has led to a better understanding of the functional neural systems involved in arousal or activation processes and ultimately contributed much to our current theories of emotion. Despite evidence for the dynamic interplay between the left and right cerebral hemispheres, the concepts of cerebral balance and dynamic activation have been emphasized in the neuropsychological literature. A conceptual model is proposed herein that incorporates the unique contributions from multiple neuropsychological theories of arousal and emotion. It is argued that the cerebral hemispheres may play oppositional roles in emotion partially due to the differences in their functional specializations and in their persistence upon activation. In the presence of a threat or provocation, the right hemisphere may activate survival relevant responses partially derived from hemispheric specializations in arousal and emotional processing, including the mobilization of sympathetic drive to promote heightened blood pressure, heart rate, glucose mobilization and respiratory support necessary for the challenge. Oppositional processes and mechanisms are discussed, which may be relevant to the regulatory control over the survival response; however, the capacity of these systems is necessarily limited. A limited capacity mechanism is proposed, which is familiar within other physiological systems, including that providing for the prevention of muscular damage under exceptional demand. This capacity theory is proposed, wherein a link may be expected between exceptional stress within a neural system and damage to the neural system. These mechanisms are proposed to be relevant to emotion and emotional disorders. Discussion is provided on the

  18. Experimental and theoretical study of possible correlation between the electrochemistry of canthin-6-one and the anti-proliferative activity against human cancer stem cells

    NASA Astrophysics Data System (ADS)

    Cebrián-Torrejón, G.; Doménech-Carbó, A.; Scotti, M. T.; Fournet, A.; Figadère, B.; Poupon, E.

    2015-12-01

    This work presents an approach to study the performance of novel targets able to overcome cancer stem cell chemoresistance, based on the voltammetric data for microparticulate films of natural or synthetic alkaloids from the canthin-6-one series. A comparison of this voltammetric technique with conventional solution phase electrochemistry suggests the differences in the anti-proliferative activity of canthin-6-ones could be tentatively correlated to their different capacity to generate semiquinone radical anions. These data also match theoretical calculations.

  19. Barriers to Research Activities from the Perspective of the Students of Isfahan University of Medical Sciences

    PubMed Central

    Ashrafi-rizi, Hasan; Fateme, Zarmehr; Khorasgani, Zahra Ghazavi; Kazempour, Zahra; Imani, Sona Taebi

    2015-01-01

    Introduction: Necessity to establish a coherent and targeted research context in order to development of any country is increasingly important. But the basic step in creating an effective research context would be enrichment motivation of researchers especially students and resolve barriers of research. Therefore, the purpose of this study was to determine barriers of research activities from the perspective of students of Isfahan University of Medical Sciences. Methods: This is research. Data was collected with author made questionnaire. The study sample consisted of students from Isfahan medical university and sample size based on Krejcie and Morgan table was 357. Sampling was Stratified Random. The validity of questionnaire confirmed by Library and information professionals and reliability based on Cronbach’s Alpha was 0.933, respectively. The type of descriptive statistics was (percentage, frequency and mean) and inferential statistics (T-test, ANOVA, one-Sample Statistics) and SPSS software was used. Findings: Results showed that the mean of barriers to research activities among students of Isfahan University of Medical Sciences was 3.89 ± 0. 483. The highest mean was related to density of students’ curriculum (4.22± 0.968) and lowest mean related to lack of access to appropriate library resources. Also, the mean of research activities ’s barriers, according to aspects showed that the mean in individual barriers level (4.06±0.635) was more than other aspects: social and cultural aspects (4.01± 0.661), economical aspect (4.04± 0.787) and organizational barriers (3.78±0.503). The lowest mean was related to organizational barriers. Also there is no difference between mean of research activities’ barriers of student of Isfahan University of Medical Sciences with regarded of gender, level of education and college. Conclusion: According to results of this research, although, the main barriers between students was individual barriers such as: lack of

  20. QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP METHODS: PERSPECTIVES ON DRUG DISCOVERY AND TOXICOLOGY. (R826133)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  1. A perspective on experimental findings and theoretical explanations of novel dynamics at free surface and in freestanding thin films of polystyrene

    NASA Astrophysics Data System (ADS)

    Ngai, Kia L.; Prevosto, Daniele; Capaccioli, Simone

    2016-03-01

    Most studies of the dynamics at the surface and in thin films of polystyrene (PS) are focused on the change of glass transition temperature from the bulk value. In this perspective, we highlight three new developments in research on the dynamics of PS in high molecular weight (MW) freestanding PS thin films and at the surface of low MW PS. Novel findings from these developments require consideration of viscoelastic mechanisms with length scales longer than the segmental α-relaxation. The first development is the creep compliance measurements of high-MW PS thin films, probing not only the segmental α-relaxation, but also the polymer chain modes at higher compliance levels, including the sub-Rouse modes and the Rouse modes. The compliance data indicate the relaxation times of the sub-Rouse modes are reduced in thinner films like that of the segmental α-relaxation but to a much less extent. The second development is the novel observation of two glass transitions in freestanding polystyrene thin films by ellipsometry. The upper and lower glass transitions occurs, respectively, at temperatures ? and ?, both are below the bulk glass transition temperature. While the lower transition at ? is associated with the segmental α-relaxation, the only viable explanation of the origin of the upper transition at ? is from another intrinsic viscoelastic mechanism of PS, and not at different location of the film. Supported by various experiments on PS and other polymers, we show that the sub-Rouse modes are cooperative and coupled to density, and hence giving rise to the upper glass transition in freestanding PS films. The sub-Rouse relaxation times will increase on physical ageing, and bring along an increase in density of the freestanding film due to the coupling. This prediction can be checked by performing ageing experiment. The third development is the reduction of viscosity at the free surface of low MW PS. Since viscous flow of low MW PS is definitely carried out by the

  2. Theoretical Issues

    SciTech Connect

    Marc Vanderhaeghen

    2007-04-01

    The theoretical issues in the interpretation of the precision measurements of the nucleon-to-Delta transition by means of electromagnetic probes are highlighted. The results of these measurements are confronted with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, large-Nc relations, perturbative QCD, and QCD-inspired models. The link of the nucleon-to-Delta form factors to generalized parton distributions (GPDs) is also discussed.

  3. Sociocultural perspectives on physical activity in the lives of older African American and American Indian women: a cross cultural activity participation study.

    PubMed

    Henderson, K A; Ainsworth, B E

    2000-01-01

    Illuminating the diversity and sociocultural specificity of women's experiences may be important if healthy lifestyles and quality of life are to be achieved. The incidence of cardiovascular disease linked to physical inactivity is high among African American and American Indian women. If more is understood about the experience of physical activity involvement, healthier living might be encouraged. Therefore, the purpose of this study was to explore the sociocultural meanings of physical activity for older (over the age of 40 years) African American and American Indian women who participated in the Cross Cultural Activity Participation Study (CAPS). Through qualitative in-depth interviews, we explored how sociocultural perspectives are related to perceptions about physical activity. Gender and other sociocultural factors influenced physical involvement on a continuum from negligible to significant. Both groups interviewed showed evidence that opportunities for physical activity in their free time did not always exist for them. For African American women, history and daily living issues were important factors limiting their involvement. Marginality limited American Indian women, but their cultural pride was often a source of physical activity. The juxtaposition of cultural and personal values emerged as a determinant of physical activity involvement among the women in this study. A further expansion of cultural and personal life situation perspectives is recommended to help understand the complex dimensions of physical activity as it relates to healthy living.

  4. Leon Cooper's Perspective on Teaching Science: An Interview Study

    ERIC Educational Resources Information Center

    Niaz, Mansoor; Klassen, Stephen; McMillan, Barbara; Metz, Don

    2010-01-01

    The authors of this paper portray the perspective of Professor Leon Cooper, a theoretical physicist, Nobel laureate, active researcher, and physics textbook author, on teaching science and on the nature of science (NOS). The views presented emerged from an interview prepared by the authors and responded to in writing by Professor Cooper. Based on…

  5. New Look on 3-Hydroxyiminoflavanone and Its Palladium(II) Complex: Crystallographic and Spectroscopic Studies, Theoretical Calculations and Cytotoxic Activity.

    PubMed

    Kasprzak, Maria; Fabijańska, Małgorzata; Chęcińska, Lilianna; Szmigiero, Leszek; Ochocki, Justyn

    2016-04-13

    This work presents the synthesis, spectroscopic properties and single-crystal X-ray examination of the structure of 3-hydroxyiminoflavanone and its palladium complex. It presents the results of NMR (Nuclear Magnetic Resonance) spectroscopy, electron-density studies based on X-ray wavefunction refinement and theoretical calculations combined with QTAIM (Quantum Theory of Atoms in Molecules) and ELI-D (Electron Localizability Indicator) analyses. These offer an interesting new insight into the structures and behavior of flavanone and its complex, in solid state and in solution. The study also examines the cytotoxicity of the ligand and its complex against three human ovarian and lung cancer cell lines.

  6. Treating Depression and Depression-Like Behavior with Physical Activity: An Immune Perspective

    PubMed Central

    Eyre, Harris A.; Papps, Evan; Baune, Bernhard T.

    2012-01-01

    The increasing burden of major depressive disorder makes the search for an extended understanding of etiology, and for the development of additional treatments highly significant. Biological factors may be useful biomarkers for treatment with physical activity (PA), and neurobiological effects of PA may herald new therapeutic development in the future. This paper provides a thorough and up-to-date review of studies examining the neuroimmunomodulatory effects of PA on the brain in depression and depression-like behaviors. From a neuroimmune perspective, evidence suggests PA does enhance the beneficial and reduce the detrimental effects of the neuroimmune system. PA appears to increase the following factors: interleukin (IL)-10, IL-6 (acutely), macrophage migration inhibitory factor, central nervous system-specific autoreactive CD4+ T cells, M2 microglia, quiescent astrocytes, CX3CL1, and insulin-like growth factor-1. On the other hand, PA appears to reduce detrimental neuroimmune factors such as: Th1/Th2 balance, pro-inflammatory cytokines, C-reactive protein, M1 microglia, and reactive astrocytes. The effect of other mechanisms is unknown, such as: CD4+CD25+ T regulatory cells (T regs), CD200, chemokines, miRNA, M2-type blood-derived macrophages, and tumor necrosis factor (TNF)-α [via receptor 2 (R2)]. The beneficial effects of PA are likely to occur centrally and peripherally (e.g., in visceral fat reduction). The investigation of the neuroimmune effects of PA on depression and depression-like behavior is a rapidly developing and important field. PMID:23382717

  7. Coronal Mass Ejections from the Same Active Region Cluster: Two Different Perspectives

    NASA Astrophysics Data System (ADS)

    Cremades, H.; Mandrini, C. H.; Schmieder, B.; Crescitelli, A. M.

    2015-06-01

    The cluster formed by active regions (ARs) NOAA 11121 and 11123, approximately located on the solar central meridian on 11 November 2010, is of great scientific interest. This complex was the site of violent flux emergence and the source of a series of Earth-directed events on the same day. The onset of the events was nearly simultaneously observed by the Atmospheric Imaging Assembly (AIA) telescope onboard the Solar Dynamics Observatory (SDO) and the Extreme-Ultraviolet Imagers (EUVI) on the Sun-Earth Connection Coronal and Heliospheric Investigation (SECCHI) suite of telescopes onboard the Solar-Terrestrial Relations Observatory (STEREO) twin spacecraft. The progression of these events in the low corona was tracked by the Large Angle Spectroscopic Coronagraphs (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) and the SECCHI/COR coronagraphs on STEREO. SDO and SOHO imagers provided data from the Earth's perspective, whilst the STEREO twin instruments procured images from the orthogonal directions. This spatial configuration of spacecraft allowed optimum simultaneous observations of the AR cluster and the coronal mass ejections that originated in it. Quadrature coronal observations provided by STEREO revealed many more ejective events than were detected from Earth. Furthermore, joint observations by SDO/AIA and STEREO/SECCHI EUVI of the source region indicate that all events classified by GOES as X-ray flares had an ejective coronal counterpart in quadrature observations. These results directly affect current space weather forecasting because alarms might be missed when there is a lack of solar observations in a view direction perpendicular to the Sun-Earth line.

  8. Theoretical geology

    NASA Astrophysics Data System (ADS)

    Mikeš, Daniel

    2010-05-01

    Theoretical geology Present day geology is mostly empirical of nature. I claim that geology is by nature complex and that the empirical approach is bound to fail. Let's consider the input to be the set of ambient conditions and the output to be the sedimentary rock record. I claim that the output can only be deduced from the input if the relation from input to output be known. The fundamental question is therefore the following: Can one predict the output from the input or can one predict the behaviour of a sedimentary system? If one can, than the empirical/deductive method has changes, if one can't than that method is bound to fail. The fundamental problem to solve is therefore the following: How to predict the behaviour of a sedimentary system? It is interesting to observe that this question is never asked and many a study is conducted by the empirical/deductive method; it seems that the empirical method has been accepted as being appropriate without question. It is, however, easy to argument that a sedimentary system is by nature complex and that several input parameters vary at the same time and that they can create similar output in the rock record. It follows trivially from these first principles that in such a case the deductive solution cannot be unique. At the same time several geological methods depart precisely from the assumption, that one particular variable is the dictator/driver and that the others are constant, even though the data do not support such an assumption. The method of "sequence stratigraphy" is a typical example of such a dogma. It can be easily argued that all the interpretation resulting from a method that is built on uncertain or wrong assumptions is erroneous. Still, this method has survived for many years, nonwithstanding all the critics it has received. This is just one example of the present day geological world and is not unique. Even the alternative methods criticising sequence stratigraphy actually depart from the same

  9. Microwave Assistant Synthesis, Antifungal Activity and DFT Theoretical Study of Some Novel 1,2,4-Triazole Derivatives Containing Pyridine Moiety

    PubMed Central

    Sun, Guo-Xiang; Yang, Ming-Yan; Shi, Yan-Xia; Sun, Zhao-Hui; Liu, Xing-Hai; Wu, Hong-Ke; Li, Bao-Ju; Zhang, Yong-Gang

    2014-01-01

    In order to investigate the biological activity of novel 1,2,4-triazole compounds, seventeen novel 1,2,4-triazole derivatives containing pyridine moiety were synthesized under microwave assistant condition by multi-step reactions. The structures were characterized by 1H NMR, MS and elemental analyses. The target compounds were evaluated for their fungicidal activities against Stemphylium lycopersici (Enjoji) Yamamoto, Fusarium oxysporum. sp. cucumebrium, and Botrytis cinerea in vivo, and the results indicated that some of the title compounds displayed excellent fungicidal activities. Theoretical calculation of the title compound was carried out with B3LYP/6-31G (d,p). The full geometry optimization was carried out using 6-31G (d,p) basis set, and the frontier orbital energy, atomic net charges were discussed, and the structure-activity relationship was also studied. PMID:24815069

  10. Theoretical Mathematics

    NASA Astrophysics Data System (ADS)

    Stöltzner, Michael

    Answering to the double-faced influence of string theory on mathematical practice and rigour, the mathematical physicists Arthur Jaffe and Frank Quinn have contemplated the idea that there exists a `theoretical' mathematics (alongside `theoretical' physics) whose basic structures and results still require independent corroboration by mathematical proof. In this paper, I shall take the Jaffe-Quinn debate mainly as a problem of mathematical ontology and analyse it against the backdrop of two philosophical views that are appreciative towards informal mathematical development and conjectural results: Lakatos's methodology of proofs and refutations and John von Neumann's opportunistic reading of Hilbert's axiomatic method. The comparison of both approaches shows that mitigating Lakatos's falsificationism makes his insights about mathematical quasi-ontology more relevant to 20th century mathematics in which new structures are introduced by axiomatisation and not necessarily motivated by informal ancestors. The final section discusses the consequences of string theorists' claim to finality for the theory's mathematical make-up. I argue that ontological reductionism as advocated by particle physicists and the quest for mathematically deeper axioms do not necessarily lead to identical results.

  11. Using Activity Theory to Model the Taiwan Atayal Students' Classroom Mathematical Activity

    ERIC Educational Resources Information Center

    Huang, Chih-Hsien; Lin, Fou-Lai

    2013-01-01

    From the sociocultural perspective, this research utilized activity theory as the theoretical framework to analyze the influences of cultural factors for Taiwanese Atayal junior high school students' study in mathematics. The research methodology adopted grounded theory, theoretical and methodological approaches which are illustrated through…

  12. Gaining A Geological Perspective Through Active Learning in the Large Lecture Classroom

    NASA Astrophysics Data System (ADS)

    Kapp, J. L.; Richardson, R. M.; Slater, S. J.

    2008-12-01

    NATS 101 A Geological Perspective is a general education course taken by non science majors. We offer 600 seats per semester, with four large lecture sections taught by different faculty members. In the past we have offered optional once a week study groups taught by graduate teaching assistants. Students often feel overwhelmed by the science and associated jargon, and many are prone to skipping lectures altogether. Optional study groups are only attended by ~50% of the students. Faculty members find the class to be a lot of work, mainly due to the grading it generates. Activities given in lecture are often short multiple choice or true false assignments, limiting the depth of understanding we can evaluate. Our students often lack math and critical thinking skills, and we spend a lot of time in lecture reintroducing ideas students should have already gotten from the text. In summer 2007 we were funded to redesign the course. Our goals were to 1) cut the cost of running the course, and 2) improve student learning. Under our redesign optional study groups were replaced by once a week mandatory break out sessions where students complete activities that have been introduced in lecture. Break out sessions substitute for one hour of lecture, and are run by undergraduate preceptors and graduate teaching assistants (GTAs). During the lecture period, lectures themselves are brief with a large portion of the class devoted to active learning in small groups. Weekly reading quizzes are submitted via the online course management system. Break out sessions allow students to spend more time interacting with their fellow students, undergraduate preceptors, and GTAs. They get one on one help in break out sessions on assignments designed to enhance the lecture material. The active lecture format means less of their time is devoted to listening passively to a lecture, and more time is spent peer learning an interacting with the instructor. Completing quizzes online allows students

  13. Physician-Patient Communication and Patient Compliance: A Theoretical Orientation.

    ERIC Educational Resources Information Center

    Clampitt, Phillip G.; Williams, M. Lee

    This paper synthesizes much of the literature concerning physician/patient communication as it relates to patient compliance. Using the theoretical perspective that deals with belief, attitude, intention, and behavior (a perspective generated by Martin Fishbein and Icek Ajzen), a new theoretical orientation for predicting patient compliance is…

  14. Using Web-Based Instruction to Promote Active Learning: Learners' Perspectives

    ERIC Educational Resources Information Center

    Lee, Lina

    2005-01-01

    This article reports classroom research on learners' perspectives on Web-based instruction that utilizes the "Blackboard" course management system. The Web-based instruction aims to provide and support collaborative learning while fostering learners' autonomy and accountability. The article also provides a description of the course…

  15. The relationship between molecular structure and biological activity of alkali metal salts of vanillic acid: Spectroscopic, theoretical and microbiological studies

    NASA Astrophysics Data System (ADS)

    Świsłocka, Renata; Piekut, Jolanta; Lewandowski, Włodzimierz

    In this paper we investigate the relationship between molecular structure of alkali metal vanillate molecules and their antimicrobial activity. To this end FT-IR, FT-Raman, UV absorption and 1H, 13C NMR spectra for lithium, sodium, potassium, rubidium and caesium vanillates in solid state were registered, assigned and analyzed. Microbial activity of studied compounds was tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Proteus vulgaris, Bacillus subtilis and Candida albicans. In order to evaluate the dependence between chemical structure and biological activity of alkali metal vanillates the statistical analysis was performed for selected wavenumbers from FT-IR spectra and parameters describing microbial activity of vanillates. The geometrical structures of the compounds studied were optimized and the structural characteristics were determined by density functional theory (DFT) using at B3LYP method with 6-311++G** as basis set. The obtained statistical equations show the existence of correlation between molecular structure of vanillates and their biological properties.

  16. Crystal structure and theoretical study of IR and 1H and 13C NMR spectra of cordatin, a natural product with antiulcerogenic activity

    NASA Astrophysics Data System (ADS)

    Brasil, Davi S. B.; Alves, Cláudio N.; Guilhon, Giselle M. S. P.; Muller, Adolfo H.; Secco, Ricardo De S.; Peris, Gabriel; Llusar, Rosa

    Cordatin is a furan diterpenoid with a clerodane skeleton isolated from Croton palanostigma Klotzsch (Euphorbiaceae). This natural product shows significant antiulcerogenic activity, similar to cimetidine (Tagamet®), a compound used for the treatment of peptic ulcers. The crystal structure of cordatin was obtained by X-ray diffraction and its geometrical parameters were compared with theoretical calculations at the B3LYP theory level. The IR and NMR (1H and 13C chemical shifts and coupling constants) spectra were obtained and compared with the theoretical calculations. The B3LYP theory level, with the 6-31G(d,p) and 6-311G(d,p) basis set, provided IR absorption values close to the experimental data. Moreover, theoretical NMR parameters obtained in both gas phase and chloroform solvent at the B3PW91/DGDZVP, B3LYP/6-311+G(2d,p), and B3PW91/6-311+G(2d,p) levels showed good correlations with the experimental results.

  17. Sampling artifacts in active air sampling of semivolatile organic contaminants: Comparing theoretical and measured artifacts and evaluating implications for monitoring networks.

    PubMed

    Melymuk, Lisa; Bohlin-Nizzetto, Pernilla; Prokeš, Roman; Kukučka, Petr; Klánová, Jana

    2016-10-01

    The effects of sampling artifacts are often not fully considered in the design of air monitoring with active air samplers. Semivolatile organic contaminants (SVOCs) are particularly vulnerable to a range of sampling artifacts because of their wide range of gas-particle partitioning and degradation rates, and these can lead to erroneous measurements of air concentrations and a lack of comparability between sites with different environmental and sampling conditions. This study used specially adapted filter-sorbent sampling trains in three types of active air samplers to investigate breakthrough of SVOCs, and the possibility of other sampling artifacts. Breakthrough volumes were experimentally determined for a range of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in sampling volumes from 300 to 10,000 m(3), and sampling durations of 1-7 days. In parallel, breakthrough was estimated based on theoretical sorbent-vapor pressure relationships. The comparison of measured and theoretical determinations of breakthrough demonstrated good agreement between experimental and estimated breakthrough volumes, and showed that theoretical breakthrough estimates should be used when developing air monitoring protocols. Significant breakthrough in active air samplers occurred for compounds with vapor pressure >0.5 Pa at volumes <700 m(3). Sample volumes between 700 and 10,000 m(3) may lead to breakthrough for compounds with vapor pressures between 0.005 and 0.5 Pa. Breakthrough is largely driven by sample volume and compound volatility (therefore indirectly by temperature) and is independent of sampler type. The presence of significant breakthrough at "typical" sampling conditions is relevant for air monitoring networks, and may lead to under-reporting of more volatile SVOCs.

  18. Mixed ligand Cu(II)N2O2 complexes: biomimetic synthesis, activities in vitro and biological models, theoretical calculations.

    PubMed

    Li, Chen; Yin, Bing; Kang, Yifan; Liu, Ping; Chen, Liang; Wang, Yaoyu; Li, Jianli

    2014-12-15

    Three new mixed ligand Cu(II)N2O2 complexes, namely, [Cu(II)(2-A-6-MBT)2(m-NB)2] (1), [Cu(II)(2-ABT)2(m-NB)2] (2), and [Cu(II)(2-ABT)2(o-NB)2] (3), (2-A-6-MBT = 2-amino-6-methoxybenzothiazole, m-NB = m-nitrobenzoate, 2-ABT = 2-aminobenzothiazole, and o-NB = o-nitrobenzoate), have been prepared by the biomimetic synthesis strategy, and their structures were determined by X-ray crystallography studies and spectral methods. These complexes exhibited the effective superoxide dismutase (SOD) activity and catecholase activity. On the basis of the experimental data and computational studies, the structure-activity relationship for these complexes was investigated. The results reveal that electron-accepting abilities of these complexes and coordination geometries have significant effects on the SOD activity and catecholase activity. Then, we found that 1 and 2 exerted potent intracellular antioxidant capacity in the model of H2O2-induced oxidative stress based on HeLa cervical cancer cells, which were screened out by the cytotoxicity assays of different kinds of cells. Furthermore, 1-3 showed the favorable biocompatibility in two different biological models: Saccharomyces cerevisiae and human vascular endothelial cells. These biological experimental data are indicative of the promising application potential of these complexes in biology and pharmacology.

  19. Health promotion: theoretical perspectives and clinical applications.

    PubMed

    Frenn, M; Malin, S

    1998-01-01

    The article addresses the realities of health promotion practice in a managed care environment, synthesizing the most important findings from the midrange theories currently guiding wellness-oriented research. Factors that have been shown to predict engagement in a number of health behaviors are identified and are formulated into a guide for clinical assessment, intervention, and outcome evaluation for clients across the life span.

  20. Human Chronotypes from a Theoretical Perspective

    PubMed Central

    Kramer, Achim; Herzel, Hanspeter

    2013-01-01

    The endogenous circadian timing system has evolved to synchronize an organism to periodically recurring environmental conditions. Those external time cues are called Zeitgebers. When entrained by a Zeitgeber, the intrinsic oscillator adopts a fixed phase relation to the Zeitgeber. Here, we systematically study how the phase of entrainment depends on clock and Zeitgeber properties. We combine numerical simulations of amplitude-phase models with predictions from analytically tractable models. In this way we derive relations between the phase of entrainment to the mismatch between the endogenous and Zeitgeber period, the Zeitgeber strength, and the range of entrainment. A core result is the “180° rule” asserting that the phase varies over a range of about 180° within the entrainment range. The 180° rule implies that clocks with a narrow entrainment range (“strong oscillators”) exhibit quite flexible entrainment phases. We argue that this high sensitivity of the entrainment phase contributes to the wide range of human chronotypes. PMID:23544070

  1. Disintegration, Recognition, and Violence: A Theoretical Perspective

    ERIC Educational Resources Information Center

    Heitmeyer, Wilhelm; Anhut, Reimund

    2008-01-01

    The literature explaining deviance, criminality, or violence offers a broad spectrum of approaches in criminology and sociology. Mostly the theories focus on specific levels of explanation like the macrolevel (for example, strain theories) or the microlevel (for example, self-control theory). This article presents a relatively new theoretical…

  2. Feminist theoretical perspectives on ethics in radiology.

    PubMed

    Condren, Mary

    2009-07-01

    The substantive safety of radiological and other medical procedures can be radically reduced by unconscious factors governing scientific thought. In addition, the historical exclusion of women from these disciplines has possibly skewed their development in directions that now need to be addressed. This paper focuses on three such factors: gendered libidos that privilege risk taking over prevention, fragmented forms of knowledge that encourage displaced forms of responsibility and group dynamics that discourage critique of accepted practices and limit the definition of one's group. The substantive safety of the practice and scientific contribution of radiologists might be considerably enhanced were the focus to switch from radiology to diagnosis. Such enlargement might redefine the brief of radiologists towards preventing as well as curing; evaluating some non-invasive and low-tech options, adopting some inclusive paradigms of clinical ecology and enlarging group identities to include those currently excluded through geography or social class from participating in the benefits of science.

  3. [The serial murder: a few theoretical perspectives].

    PubMed

    Leistedt, S; Linkowski, P

    2011-01-01

    Despite numbers of publications and effort to try to establish the definition, the classification, the epidemiology, the clinical aspects and the psychopathology of serial killers, a universal consensus seems to say the least. Crime, though reduced in some countries, appears to impact more and more consistent worldwide, generating controversial ideas and a multitude of possible explanations. The serial killer usually presents as a caucasian man, aged between 20 and 40 years, often embedded socially and in his family, but with serious psychiatric, personal and especially family history. Usually acting alone, the serial killer plans a crime well in advance, but sometimes within the scope of impulsivity for a minority, the victim not being previously selected. In the latter case, an actual mental illness like psychosis is found. It is clear from numerous psychopathological studies conducted so far that most serial killers are defined as psychopathic sexual sadists, whose childhood was difficult, if not flouted, punctuated by physical and psychological violence situations. In addition, pervasive fantasies combined with thoughts of death, sex and violence are as much in common with the original acts of which they are the instigators. Beyond a relentless media that is constantly watering the public with stories and pictures depicting them as such, serial killers remain an enigma. We can therefore attempt to answer the various questions raised by this phenomenon, the way these people operate and how we can curb the rise, thanks to the neurobiological and neurophysiological approaches that science offers us.

  4. A New Theoretical Perspective of Cognitive Abilities

    ERIC Educational Resources Information Center

    Lynch, Sharon A.; Warner, Laverne

    2012-01-01

    Defining intelligence is a puzzle that has challenged educators and researchers for years. More recently, professionals are acknowledging that individuals possess many facets of intelligence and that learning is a complex combination of genetic factors, environmental influences, and life experiences that affect learning in unique ways (Salvia,…

  5. Psychopathy in women: theoretical and clinical perspectives

    PubMed Central

    Wynn, Rolf; Høiseth, Marita H; Pettersen, Gunn

    2012-01-01

    Prior research on psychopathy has primarily focused on the problem in men. Only a few studies have examined whether psychopathy even exists in women, and if so, how the disorder manifests itself in them. This paper presents a narrative review of the literature on gender and psychopathy. We briefly discuss why this is an important topic for women and we discuss its causes. The concept of psychopathy is defined and related to the diagnostic systems. The discussion includes a presentation of diagnostic tools, including the Hare Psychology Checklist – Revised, which are examined in relationship to the importance of biological gender. While emphasizing the similarities as well as the differences between the sexes, we discuss the matters of prevalence, behavioral expressions, comorbidity, progression, and treatment of the disorder. PMID:22723733

  6. Migration, crisis and theoretical conflict.

    PubMed

    Bach, R L; Schraml, L A

    1982-01-01

    The nature of the distinction between the equilibrium and historical-structuralist positions on migration is examined. Theoretical and political differences in the two positions are considered both historically and in the context of the current global economic crisis. The proposal of Wood to focus on households as a strategy for integrating the two perspectives and for achieving a better understanding of migration and social change is discussed.

  7. Marketing active transportation to school to improve children's health: Utilizing parental perspectives from an inner-city environment.

    PubMed

    Royne, Marla B; Ivey, Stephanie S; Levy, Marian; Fox, Alexa K; Roakes, Susan L

    2016-01-01

    Thirty years ago, nearly half of the children in the United States walked or rode their bikes to school. Today, less than 15% of children actively commute to school. With the growing obesity epidemic, encouraging children to walk or bike to school has become a national priority. This research examines factors that influence parental decisions allowing their children to walk to school in an urban environment to identify effective marketing and communication strategies to reach those parents. Results indicate differences in parental perspectives across populations; suggestions for effectively marketing the Safe Routes to School program to minority populations are provided.

  8. Alienation in Mathematics Education: Critique and Development of Neo-Vygotskian Perspectives

    ERIC Educational Resources Information Center

    Williams, Julian

    2016-01-01

    This paper aims to critique and develop neo-Vygotskian work in mathematics education from (i) within the Vygotskian and activity theoretic tradition, and where necessary from (ii) a Bourdieusian perspective. First, I critique Roth and Radford's (2011) version of Cultural-historical Activity Theory, suggesting that a classroom episode presented as…

  9. The Activity-Based Approach to Achieving Theoretical and Practical Consensus in Pedagogy of N. F. Talyzina

    ERIC Educational Resources Information Center

    Chapaev, Nikolay K.; Akimova, Olga B.; Selivanov, Andrey V.; Shaforostova, Tatiana V.

    2016-01-01

    The relevance of the problem under study is based on the necessity to solve the permanent problem of the unity of theory and practice in the content of students' cognitive activity in the modern conditions. The purpose of the article is to analyze and to generalize the main concepts of pedagogy by N.F. Talyzina for implementation of the…

  10. Theoretical studies of the activation mechanism of histamine H sub 2 -receptors: Dimaprit and the receptor model

    SciTech Connect

    Pardo, L.; Mazurek, A.P.; Osman, R.; Weinstein, H. )

    1989-01-01

    Ab initio quantum mechanical calculations are used to explore the interaction of dimaprit, a histamine H,-receptor agonist, with a molecular complex designed to model the specific recognition of histamine, and the H{sub 2}-receptor activation mechanism triggered by the binding of the ligand. The stabilization of several isomeric forms of the isothiourea moiety of dimaprit in the receptor model is considered, including models for the monocationic and dicationic forms that are likely to exist under physiological conditions. The energetics of proton transfer from a receptor site to the ligand are evaluated in the presence and absence of models for other sites in the receptor. The energetic contribution of ligand desolvation to the various steps in the receptor binding and activation mechanism is estimated from calculations of the enthalpy of solvation in water represented as a continuum dielectric. The results indicate that the most likely manner in which dimaprit mimics the binding of histamine to the proposed proton donor site in the H{sub 2}-receptor model requires the sulfur in the isothiourea moiety of dimaprit to act as the proton acceptor in the activation mechanism. The simulation of this mechanism reveals its feasibility and indicates that the monocation form of dimaprit, rather than the dication, is likely to be the physiologically active species.

  11. Copper(II) complexes with new fluoroquinolones: Synthesis, structure, spectroscopic and theoretical study, DNA damage, cytotoxicity and antiviral activity.

    PubMed

    Dorotíková, Sandra; Kožíšková, Júlia; Malček, Michal; Jomová, Klaudia; Herich, Peter; Plevová, Kristína; Briestenská, Katarína; Chalupková, Anna; Mistríková, Jela; Milata, Viktor; Dvoranová, Dana; Bučinský, Lukáš

    2015-09-01

    Copper(II) complexes with fluoroquinolones in the presence of the nitrogen donor heterocyclic ligands 1,10-phenanthroline have been considered in detail. The phenanthroline moiety was introduced into the ligand environment with the aim to determine whether the nuclease activity is feasible. All suitable X-ray structures of the complexes under study reveal a distorted square pyramidal coordination geometry for Cu(II) atom. The conformational and spectroscopic (FT-IR and UV-visible) behavior has been analyzed and has been interpreted with respect to B3LYP/6-311G* calculations including molecular dynamics. The ability of the complexes to cleave DNA was studied by agarose gel electrophoresis with plasmid DNA pBSK+. The results have confirmed that the complexes under study behave as the chemical nucleases. Nuclease like activity in the absence of hydrogen peroxide allows us to deduce an interaction of the complexes with the DNA resulting in the conversion of supercoiled circular DNA to the nicked form. The DNA cleavage activity enhanced by the presence of hydrogen peroxide demonstrates the participation of reactive oxygen species, such as superoxide radical anions and hydroxyl radicals which presence was confirmed independently using the standard radical scavenging agents. It has been suggested that the radical formation through the Fenton/Haber-Weiss reaction is mediated by the redox cycling mechanisms with the participation of cupric/cuprous ions. Cytotoxic activity was evaluated as the 50% cytotoxic concentration (CC50). The potential effects of tested compounds on replication of murine gammaherpesvirus 68 (MHV-68) under in vitro conditions were also evaluated. However, no antiviral activity against MHV-68 was observed.

  12. Synthesis, antimicrobial evaluation and theoretical prediction of NMR chemical shifts of thiazole and selenazole derivatives with high antifungal activity against Candida spp.

    NASA Astrophysics Data System (ADS)

    Łączkowski, Krzysztof Z.; Motylewska, Katarzyna; Baranowska-Łączkowska, Angelika; Biernasiuk, Anna; Misiura, Konrad; Malm, Anna; Fernández, Berta

    2016-03-01

    Synthesis and investigation of antimicrobial activities of novel thiazoles and selenazoles is presented. Their structures were determined using NMR, FAB(+)-MS, HRMS and elemental analyses. To support the experiment, theoretical calculations of the 1H NMR shifts were carried out for representative systems within the DFT B3LYP/6-311++G** approximation which additionally confirmed the structure of investigated compounds. Among the derivatives, compounds 4b, 4h, 4j and 4l had very strong activity against reference strains of Candida albicans ATCC and Candida parapsilosis ATCC 22019 with MIC = 0.49-7.81 μg/ml. In the case of compounds 4b, 4c, 4h - 4j and 4l, the activity was very strong against of Candida spp. isolated from clinical materials, i.e. C. albicans, Candida krusei, Candida inconspicua, Candida famata, Candida lusitaniae, Candida sake, C. parapsilosis and Candida dubliniensis with MIC = 0.24-15.62 μg/ml. The activity of several of these was similar to the activity of commonly used antifungal agent fluconazole. Additionally, compounds 4m - 4s were found to be active against Gram-positive bacteria, both pathogenic staphylococci Staphylococcus aureus ATCC with MIC = 31.25-125 μg/ml and opportunistic bacteria, such as Staphylococcus epidermidis ATCC 12228 and Micrococcus luteus ATCC 10240 with MIC = 7.81-31.25 μg/ml.

  13. Theoretical Model of Drag Force Impact on a Model International Space Station (ISS) Satellite due to Solar Activity

    NASA Astrophysics Data System (ADS)

    Nwankwo, Victor U. J.; Chakrabarti, Sandip Kumar

    The International Space Station (ISS) is the single largest and most complex scientific and engineering space structure in human history. Its orbital parameters make it extremely vulnerable to severe atmospheric drag force. Complex interactions between solar energetic particles, ultraviolet (UV) radiation with atmosphere and geomagnetic field cause heating and subsequent expansion of the upper atmosphere. This condition increases drag on low Earth orbit satellites (LEOSs) and varies with current space weather conditions. In this work, we apply the NRLMSISE-00 empirical atmospheric density model, as a function of space environmental parameters, to model drag force impact on a model LEOS during variation of solar activity. Applying the resulting drag model on a model ISS satellite we observe that depending on the severity and/or stage of solar activity or cycle, a massive artificial satellite could experience orbit decay rate of up to 2.95km/month during solar maximum and up to 1km/month during solar minimum.

  14. Synthesis, structural characterization, antimicrobial activities and theoretical investigations of some 4-(4-aminophenylsulfonyl) phenylimino) methyl)-4-(aryldiazenyl) phenol

    NASA Astrophysics Data System (ADS)

    Ghasemian, Motaleb; Kakanejadifard, Ali; Karami, Tahereh

    2016-11-01

    The azo-azomethine dyes with a different substitution have been designed from the reaction of 4,4‧-diaminodiphenyl sulfone with 2-hydroxy-5-(aryldiazenyl)benzaldehyde. The compounds have been characterized by elemental analysis, Mass, IR, UV-Vis, TGA-DTA and NMR spectroscopy. The solvatochromism behaviors, effects of substitution and pH on the electronic absorption spectra of dyes were evaluated. The in vitro antimicrobial activities were also screened for their potential for antibiotic activities by broth micro dilution method. Also, the optimum molecular geometries, molecular electrostatic potential (MEP), nucleus-independent chemical shift (NICS) and frontier molecular orbitals (FMO), vibrational spectra (IR) and electronic absorption (UV-Vis) spectra of the title compounds have been investigated with the help of DFT and TDDFT methods with 6-311 ++G(d,p) basis sets and PCM calculations. The results of the calculations show excellent agreement with the experimental value.

  15. A theoretical model for the study of active and passive smoking in military women: an at-risk population.

    PubMed

    Martinelli, A M

    1999-07-01

    This paper presents a model designed for the study of active and passive smoking in military women with children. Some constructs have been adapted from a transtheoretical model of behavior change. Transtheoretical model constructs of relevance to this model include (1) stages of behavior change, (2) decisional balance, and (3) self-efficacy. Other model constructs include (1) personal and situational factors, (2) a mother's self-efficacy to reduce the child's smoke exposure, (3) a mother's expectation for the child's smoke exposure, (4) smoke avoidance, (5) nicotine dependence, and (6) social support for quitting smoking. The occurrence of health problems associated with smoking is the outcome variable. The results of a study under way at present may support the use of this model and may make data available to substantiate the need for behavior-specific interventions designed to prevent and reduce active and passive smoking among military personnel.

  16. Structure-activity relationships for novel drug precursor N-substituted-6-acylbenzothiazolon derivatives: A theoretical approach

    NASA Astrophysics Data System (ADS)

    Sıdır, Yadigar Gülseven; Sıdır, İsa

    2013-08-01

    In this study, the twelve new modeled N-substituted-6-acylbenzothiazolon derivatives having analgesic analog structure have been investigated by quantum chemical methods using a lot of electronic parameters and structure-activity properties; such as molecular polarizability (α), dipole moment (μ), EHOMO, ELUMO, q-, qH+, molecular volume (Vm), ionization potential (IP), electron affinity (EA), electronegativity (χ), molecular hardness (η), molecular softness (S), electrophilic index (ω), heat of formation (HOF), molar refractivity (MR), octanol-water partition coefficient (log P), thermochemical properties (entropy (S), capacity of heat (Cv)); as to investigate activity relationships with molecular structure. The correlations of log P with Vm, MR, ω, EA, EHOMO - ELUMO (ΔE), HOF in aqueous phase, χ, μ, S, η parameters, respectively are obtained, while the linear relation of log P with IP, Cv, HOF in gas phase are not observed. The log P parameter is obtained to be depending on different properties of compounds due to their complexity.

  17. Theoretical Study on Highly Active Bifunctional Metalloporphyrin Catalysts for the Coupling Reaction of Epoxides with Carbon Dioxide.

    PubMed

    Hasegawa, Jun-Ya; Miyazaki, Ray; Maeda, Chihiro; Ema, Tadashi

    2016-10-01

    Highly active bifunctional metalloporphyrin catalysts were developed for the coupling reaction of epoxides with CO2 to produce cyclic carbonates. The bifunctional catalysts have both quaternary ammonium halide groups and a metal center. To elucidate the roles of these catalytic groups, DFT calculations were performed. Control reactions using tetrabutylammonium halide as a catalyst were also investigated for comparison. In the present article, the results of our computational studies are overviewed. The computational results are consistent with the experimental data and are useful for elucidating the structure-activity relationship. The key features responsible for the high catalytic activity of the bifunctional catalysts are as follows: 1) the cooperative action of the halide anion (nucleophile) and the metal center (Lewis acid); 2) the near-attack conformation, leading to the efficient opening of the epoxide ring in the rate-determining step; and 3) the conformational change of the quaternary ammonium cation to stabilize various anionic species generated during catalysis, in addition to the robustness (thermostability) of the catalysts.

  18. Synthesis, characterization and catecholase-like activity of new Schiff base metal complexes derived from visnagin: Theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Beyazit, Neslihan; Çatıkkaş, Berna; Bayraktar, Şahin; Demetgül, Cahit

    2016-09-01

    A new tetradentate, unsymmetrical Schiff base ligand (H2L) containing a donor set of N2O2 and its mononuclear Cu(II) and Fe(II) complexes ([CuL] and [FeL]), were synthesized and characterized on the basis of their elemental analysis, FT-IR, Raman, 1H and 13C NMR spectra, electronic and mass spectra, molar conductivity and magnetic susceptibility measurements. Density functional theory (DFT) calculations were performed in order to clarify molecular structures, 1H NMR and 13C NMR chemical shift values, frontier molecular orbitals (FMOs), nonlinear optical properties and map of molecular electrostatic potential (MEP) of the title molecules. In agreement with trials, the results provide a full explanation of the highest efficiency observed for the compounds in relation to the electronic and the structural characteristics. The catecholase-like activity of the complexes toward the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to the corresponding quinone showed that both complexes have moderate catalytic activity. [FeL] shows higher activity (kcat = 26.4 h-1) than that of [CuL] (kcat = 23.4 h-1).

  19. Synthesis, characterization, theoretical study and biological activities of oxovanadium (IV) complexes with 2-thiophene carboxylic acid hydrazide.

    PubMed

    Jabeen, Mudassir; Ali, Saqib; Shahzadi, Saira; Sharma, Saroj K; Qanungo, Kushal

    2014-07-05

    Oxovanadium (IV) complexes (1)-(3) have been synthesized by treating 2-thiophene carboxylic acid hydrazide with VOSO4⋅xH2O and VCl3(THF)3 in different M/L ratios. These complexes have been characterized by elemental analysis, UV-vis, FT-IR and mass spectrometry. The FT-IR data predicts the bidentate nature of the ligand which is also confirmed by semi-empirical study. Mass spectrometric data shows that molecular ion peak is only observed for 2-thiophene carboxylic acid hydrazide. The ESP map and thermodynamic parameters shows the presence of partial charge on atoms and stability of synthesized oxovanadium complexes, respectively. DNA binding study of complexes (1)-(3) was carried out by UV-vis and cyclic voltammetric methods which suggests the intercalative binding mode of the complexes with DNA. Cytotoxicity was checked by brine shrimp lethality assay and complex (1) showed greater cytotoxicity towards Artemia salina as compared to free ligand. Immuno-modulatory activity data shows that hydrazide ligand was more active as compared to oxovanadium complexes and standard drug. Complex (2) shows significant urease inhibition activity. The ligand and synthesized complexes were found inactive against all tested bacterial and fungal strains.

  20. A Piagetian Constructivist Perspective on Curriculum Development.

    ERIC Educational Resources Information Center

    London, Clement B. G.

    1990-01-01

    Focuses specifically on Jean Piaget's theory of development. Examines Piaget's ideas about constructivism and explores the application of this theoretical perspective to the conceptualization of curriculum development. (MG)

  1. A theoretical study of the high-latitude winter F region at solar minimum for low magnetic activity

    NASA Astrophysics Data System (ADS)

    Sojka, J. J.; Raitt, W. J.; Schunk, R. W.

    1981-02-01

    A simple plasma convection model is combined with an ionospheric-atmospheric composition model in order to study the high-latitude winter F region at the solar minimum for low magnetic activity. The high latitude ionospheric features, such as the main trough, the ionization hole, the tongue of ionization, the aurorally produced ionization peaks, and the universal time effects are a natural consequence of the competition between the various chemical and transport processes known to be operating in the high-latitude ionosphere. In the polar hole, the F region peak electron density is below 300 km, and the dominant process at 300 km for NO(+) ions is diffusion.

  2. Theoretical Study of an Actively Mode-Locked Fiber Laser Stabilized by an Intracavity Fabry-Perot Etalon: Linear Regime

    DTIC Science & Technology

    2007-07-01

    an actively mode-locked fiber laser stabilized by an intracavity Fabry–Perot etalon: linear regime Yurij Parkhomenko,1 Moshe Horowitz,1,* Curtis R... Menyuk ,2 and Thomas F. Carruthers3,4 1Department of Electrical Engineering, Technion–Israel Institute of Technology, Haifa 32000, Israel 2Department of...Naval Research aboratory. C. R. Menyuk can be reached via e-mail at enyuk@umbc.edu, and T. F. Carruthers can be reached ia e-mail at tcarruth@nsf.gov

  3. A joint application of spectroscopic, electrochemical and theoretical approaches in evaluation of the radical scavenging activity of 3-OH flavones and their iron complexes towards different radical species.

    PubMed

    Dimitrić Marković, Jasmina M; Marković, Zoran S; Pašti, Igor A; Brdarić, Tanja P; Popović-Bijelić, Ana; Mojović, Miloš

    2012-06-28

    Combined spectroscopic (UV/visible, MS and EPR), electrochemical (CV) and theoretical approaches were used to evaluate the relevant interactions of morin and quercetin, as well as their respective iron(III) complexes with DPPH, tempone, hydroxyl and superoxide radicals. The results on iron complexation specify the stoichiometry and the relevant structural forms entering the chelation of the molecules. The spectroscopic DPPH assay shows better antioxidant activity of quercetin and its iron complex both in terms of EC(50) values and stoichiometry. The results of 2-deoxyribose degradation suggest that antioxidant activities of morin and quercetin may originate from their combined effect of iron chelation and radical scavenging. The distinctive difference in the EPR spectra of morin and quercetin radicals suggests different positions of the radical centers which may account for different sequences of their activities towards investigated radicals. Activity ranking of quercetin and morin, established by cyclic voltammetry, confirms their activity sequence obtained by EPR results and is also in agreement with the results of conformational analysis. The equilibrium geometries, optimized with the M052X functionals and 6-311G(d,p) basis set, predict structural modifications between the ligand molecules in the free state and in the complex structures. The arguments gained through experimental results can also be rationalized in terms of overall molecular geometry and structural features governing antioxidant behavior i.e. substitution pattern of the ring B.

  4. Intramolecular hydroalkoxylation of non-activated C=C bonds catalysed by zeolites: an experimental and theoretical study.

    PubMed

    Pérez-Mayoral, Elena; Matos, Ines; Nachtigall, Petr; Položij, Miroslav; Fonseca, Isabel; Vitvarová-Procházková, Dana; Čejka, Jiří

    2013-06-01

    The high activity and selectivity of zeolites in the cyclisation of unsaturated alcohols is reported for the first time; the details of a reaction mechanism based on quantum chemical calculations are also provided. The high efficiency of zeolites MFI, BEA and FAU in the cyclisation of unsaturated alcohols (cis-decen-1-ol, 6-methylhept-5-en-2-ol and 2-allylphenol) to afford oxygen-containing heterocyclic rings is demonstrated. The best catalytic performance is found for zeolites with the optimum concentration of Brønsted acid sites (ca. 0.2 mmol g(-1)) and the minimum number of Lewis acid sites. It is proposed that the efficiency of the catalysts is reduced by the existence of the so-called dual site, at which a molecule of unsaturated alcohol can simultaneously interact with two acid sites (an OH group with one and the double bond with the other Brønsted site), which increases the interaction strength. The formation of such adsorption complexes leads to a decrease in the catalyst activity because of (i) an increase in the reaction barrier, (ii) an unfavourable conformation and (iii) diffusion limitations. A new procedure for the preparation of tetrahydrofurans and pyrans over zeolite catalysts provides important oxygen-containing heterocycles with numerous applications.

  5. A theoretical study of the global F region for June solstice, solar maximum, and low magnetic activity

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.; Schunk, R. W.

    1985-01-01

    A time-dependent, three-dimensional, multi-ion model of the ionospheric F region at 120-800 km altitude is presented. Account is taken of field-aligned diffusion, cross-field electrodynamic drifts in equatorial and high latitude regions, interhemispheric flow, thermospheric winds, polar wind escape, energy-dependent chemical reactions and neutral composition changes. Attention is also given to the effects of ion production by solar EUV radiation and auroral precipitation, thermal conduction, diffusion-thermal heat flow, local heating and cooling processes, offsets between the geomagnetic and geographic poles, and bending of field lines near the magnetic equator. The model incorporates all phenomena described by previous models and can be applied to tracing magnetic storm and substorm disturbances from high to low latitudes on a global scale. Sample results are provided for ionospheric features during a June solstice, the solar maximum and in a period of low geomagnetic activity. The model will eventually be used to study coupled ionosphere-thermosphere activity.

  6. Enhanced photocatalytic activity of anatase-TiO2 nanoparticles by fullerene modification: A theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Qi, Kezhen; Selvaraj, Rengaraj; Al Fahdi, Tharaya; Al-Kindy, Salma; Kim, Younghun; Wang, Gui-Chang; Tai, Cheuk-Wai; Sillanpää, Mika

    2016-11-01

    A series of fullerene (C60)-modified anatase TiO2 (a-TiO2) nanocomposites with different weight loadings of C60 were successfully synthesized by a simple solution phase method. The as-prepared C60@a-TiO2 nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET), UV-vis diffuse reflectance absorption spectra (DRS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The photocatalytic degradation of methylene blue (MB) by the neat a-TiO2 and C60@a-TiO2 nanocomposites was investigated under UV-A light irradiation, demonstrating that C60 effectively enhances the photocatalytic activity of a-TiO2 nanoparticles with an optimal amount of 2.0 wt%. By combining with the density functional theory (DFT) calculations, we investigated the electronic structures of C60@a-TiO2 hetero-interfaces to reveal the underlying principle of the C60 loading on the photocatalytic activity. It was found that the incorporation of C60 on the a-TiO2 surface not only narrowed the band gap, but also introduced an additional doping state between the valance and conduction band. Therefore, the presence of intermediate electronic state will in turn contribute to the efficient charge separation and enhanced light adsorption for the C60@a-TiO2 nanocomposites, resulting in an improved photocatalytic performance.

  7. Experimental and Theoretical Approaches for the Surface Interaction between Copper and Activated Sludge Microorganisms at Molecular Scale

    NASA Astrophysics Data System (ADS)

    Luo, Hong-Wei; Chen, Jie-Jie; Sheng, Guo-Ping; Su, Ji-Hu; Wei, Shi-Qiang; Yu, Han-Qing

    2014-11-01

    Interactions between metals and activated sludge microorganisms substantially affect the speciation, immobilization, transport, and bioavailability of trace heavy metals in biological wastewater treatment plants. In this study, the interaction of Cu(II), a typical heavy metal, onto activated sludge microorganisms was studied in-depth using a multi-technique approach. The complexing structure of Cu(II) on microbial surface was revealed by X-ray absorption fine structure (XAFS) and electron paramagnetic resonance (EPR) analysis. EPR spectra indicated that Cu(II) was held in inner-sphere surface complexes of octahedral coordination with tetragonal distortion of axial elongation. XAFS analysis further suggested that the surface complexation between Cu(II) and microbial cells was the distorted inner-sphere coordinated octahedra containing four short equatorial bonds and two elongated axial bonds. To further validate the results obtained from the XAFS and EPR analysis, density functional theory calculations were carried out to explore the structural geometry of the Cu complexes. These results are useful to better understand the speciation, immobilization, transport, and bioavailability of metals in biological wastewater treatment plants.

  8. Synthesis, molecular structure, theoretical calculation, DNA/protein interaction and cytotoxic activity of manganese(III) complex with 8-hydroxyquinoline.

    PubMed

    Thamilarasan, V; Sengottuvelan, N; Sudha, A; Srinivasan, P; Siva, A

    2015-01-01

    Manganese(III) complex (1) [Mn(8-hq)3] (where 8-hq=8-hydroxyquinoline) has been synthesized and characterized by elemental, spectral (UV-vis, FT-IR) and thermal analysis. The structure of complex (1) has been determined by single crystal X-ray diffraction studies and the configuration around manganese(III) ion was elongated octahedral coordination geometry. Density functional theory calculations were performed for ligand and its complex. Binding studies of ligand and complex 1 with calf thymus DNA (CT-DNA) was investigated by absorption, fluorescence, circular dichroic (CD) spectroscopy and viscosity measurements. Absorption spectral studies revealed that ligand and complex 1 binds to DNA groove and its intrinsic binding strength has been found to be 2.57×10(4) and 2.91×10(4)M(-1). A molecular docking study confirm that the complex 1 is a minor groove binder and was stabilized through hydrogen bonding interactions. Complex 1 exhibits a good binding propensity to bovine serum albumin (BSA) protein. The in vitro cytotoxicity study of complex 1 on breast cancer cell line (MCF-7) indicate that it has the potential to act as effective anticancer drug, with IC50 values of 3.25μM. The ligand and its complex have been screened for antimicrobial activities and the complex showed better antimicrobial activity than the free ligand.

  9. Activation of Propane C-H and C-C Bonds by Gas-Phase Pt Atom: A Theoretical Study

    PubMed Central

    Li, Fang-Ming; Yang, Hua-Qing; Ju, Ting-Yong; Li, Xiang-Yuan; Hu, Chang-Wei

    2012-01-01

    The reaction mechanism of the gas-phase Pt atom with C3H8 has been systematically investigated on the singlet and triplet potential energy surfaces at CCSD(T)//BPW91/6-311++G(d, p), Lanl2dz level. Pt atom prefers the attack of primary over secondary C-H bonds in propane. For the Pt + C3H8 reaction, the major and minor reaction channels lead to PtC3H6 + H2 and PtCH2 + C2H6, respectively, whereas the possibility to form products PtC2H4 + CH4 is so small that it can be neglected. The minimal energy reaction pathway for the formation of PtC3H6 + H2, involving one spin inversion, prefers to start at the triplet state and afterward proceed along the singlet state. The optimal C-C bond cleavages are assigned to C-H bond activation as the first step, followed by cleavage of a C-C bond. The C-H insertion intermediates are kinetically favored over the C-C insertion intermediates. From C-C to C-H oxidative insertion, the lowering of activation barrier is mainly caused by the more stabilizing transition state interaction ΔE≠int, which is the actual interaction energy between the deformed reactants in the transition state. PMID:22942766

  10. Experimental and Theoretical Approaches for the Surface Interaction between Copper and Activated Sludge Microorganisms at Molecular Scale

    PubMed Central

    Luo, Hong-Wei; Chen, Jie-Jie; Sheng, Guo-Ping; Su, Ji-Hu; Wei, Shi-Qiang; Yu, Han-Qing

    2014-01-01

    Interactions between metals and activated sludge microorganisms substantially affect the speciation, immobilization, transport, and bioavailability of trace heavy metals in biological wastewater treatment plants. In this study, the interaction of Cu(II), a typical heavy metal, onto activated sludge microorganisms was studied in-depth using a multi-technique approach. The complexing structure of Cu(II) on microbial surface was revealed by X-ray absorption fine structure (XAFS) and electron paramagnetic resonance (EPR) analysis. EPR spectra indicated that Cu(II) was held in inner-sphere surface complexes of octahedral coordination with tetragonal distortion of axial elongation. XAFS analysis further suggested that the surface complexation between Cu(II) and microbial cells was the distorted inner-sphere coordinated octahedra containing four short equatorial bonds and two elongated axial bonds. To further validate the results obtained from the XAFS and EPR analysis, density functional theory calculations were carried out to explore the structural geometry of the Cu complexes. These results are useful to better understand the speciation, immobilization, transport, and bioavailability of metals in biological wastewater treatment plants. PMID:25399801

  11. Health/Service Providers' Perspectives on Barriers to Healthy Weight Gain and Physical Activity in Pregnant, Urban First Nations Women.

    PubMed

    Darroch, Francine E; Giles, Audrey R

    2016-01-01

    The purpose of this article is to examine health/service providers' perspectives of barriers to healthy weight gain and physical activity for urban, pregnant First Nations women in Ottawa, Canada. Through the use of semi-structured interviews, we explored 15 health/service providers' perspectives on the complex barriers their clients face. By using a postcolonial feminist lens and a social determinants of health framework, we identified three social determinants of health that the health/service providers believed to have the greatest influence on their clients' weight gain and physical activity during pregnancy: poverty, education, and colonialism. Our findings are then contextualized within existing Statistics Canada and the Ottawa Neighbourhood Study data. We found that health/service providers are in a position to challenge colonial relations of power. We conclude by urging health/service providers, researchers, and policymakers alike to take into consideration the ways in which these social determinants of health and their often synergistic effects affect urban First Nations women during pregnancy.

  12. Hydroxy functionalization of non-activated C-H and C=C bonds: new perspectives for the synthesis of alcohols through biocatalytic processes.

    PubMed

    Gröger, Harald

    2014-03-17

    New perspectives through enzymes: Recent breakthroughs have been achieved in the selective hydroxy functionalization of non-activated C-H and C=C bonds. Enzymes turned out to be suitable catalysts for the ω-hydroxylation of (substituted) alkanes and regioselective hydroxylation of aromatic hydrocarbons with atmospheric oxygen as the oxidant, and the asymmetric addition of water to non-activated alkenes.

  13. A theoretical study of molecular structure, optical properties and bond activation of energetic compound FOX-7 under intense electric fields

    NASA Astrophysics Data System (ADS)

    Tao, Zhiqiang; Wang, Xin; Wei, Yuan; Lv, Li; Wu, Deyin; Yang, Mingli

    2017-02-01

    Molecular structure, vibrational and electronic absorption spectra, chemical reactivity of energetic compound FOX-7, one of the most widely used explosives, were studied computationally in presence of an electrostatic field of 0.01-0.05 a.u. The Csbnd N bond, which usually triggers the decomposition of FOX-7, is shortened/elongated under a parallel/antiparallel field. The Csbnd N bond activation energy varies with the external electric field, decreasing remarkably with the field strength in regardless of the field direction. This is attributed to two aspects: the bond weakening by the field parallel to the Csbnd N bond and the stabilization effect on the transition-state structure by the field antiparallel to the bond. The variations in the structure and property of FOX-7 under the electric fields were further analyzed with its distributional polarizability, which is dependent on the charge transfer characteristics through the Csbnd N bond.

  14. A Theoretical Study on the Antioxidant Activity of Piceatannol and Isorhapontigenin Scavenging Nitric Oxide and Nitrogen Dioxide Radicals

    PubMed Central

    Lu, Yang; Wang, AiHua; Shi, Peng; Zhang, Hui

    2017-01-01

    The antioxidant activity of naturally occurring stilbene compounds piceatannol (PIC) and isorhapontigenin (ISO) scavenging two free radicals (NO and NO2) were studied using density functional theory (DFT) method. Four reaction mechanisms have been considered: hydrogen atom transfer (HAT), radical adduct formation (RAF), single electron transfer (SET), and sequential proton loss electron transfer (SPLET). The reaction channels in water solution were traced independently, and the respective thermodynamic and kinetic parameters were obtained. We found PIC and ISO scavenge NO mainly through RAF mechanism, and scavenge NO2 through HAT mechanism. The capacity of PIC scavenging NO2 is much higher than ISO, but the reactivity of scavenging NO is lower than ISO. PMID:28068377

  15. Dopaminergic Reward Sensitivity Can Promote Adolescent Health: A New Perspective on the Mechanism of Ventral Striatum Activation

    PubMed Central

    Telzer, Eva H.

    2015-01-01

    The prevailing view in the field of adolescent brain development is that heightened activity in the mesolimbic dopaminergic reward system serves as a liability, orienting adolescents towards risky behaviors, increasing their sensitivity to social evaluation and loss, and resulting in compromised well-being. Several findings inconsistent with this deficit view challenge the perspective that adolescent reward sensitivity largely serves as a liability and highlights the potential adaptive function that heightened striatal reactivity can serve. The goal of this review is to refine our understanding of dopaminergic reward sensitivity in adolescence. I review several studies showing that ventral striatum activation serves an adaptive function for adolescents’ health and well being relating to declines in both risk taking and depression and increases in cognitive persistence and achievement. PMID:26708774

  16. Highly Active and Stable MgAl2O4 Supported Rh and Ir Catalysts for Methane Steam Reforming: A Combined Experimental and Theoretical Study

    SciTech Connect

    Mei, Donghai; Glezakou, Vassiliki Alexandra; Lebarbier, Vanessa MC; Kovarik, Libor; Wan, Haiying; Albrecht, Karl O.; Gerber, Mark A.; Rousseau, Roger J.; Dagle, Robert A.

    2014-07-01

    In this work we present a combined experimental and theoretical investigation of stable MgAl2O4 spinel-supported Rh and Ir catalysts for the steam methane reforming (SMR) reaction. Firstly, catalytic performance for a series of noble metal catalysts supported on MgAl2O4 spinel was evaluated for SMR at 600-850°C. Turnover rate at 850°C follows the order: Pd > Pt > Ir > Rh > Ru > Ni. However, Rh and Ir were found to have the best combination of activity and stability for methane steam reforming in the presence of simulated biomass-derived syngas. It was found that highly dispersed ~2 nm Rh and ~1 nm Ir clusters were formed on the MgAl2O4 spinel support. Scanning Transition Electron Microscopy (STEM) images show that excellent dispersion was maintained even under challenging high temperature conditions (e.g. at 850°C in the presence of steam) while Ir and Rh catalysts supported on Al2O3 were observed to sinter at increased rates under the same conditions. These observations were further confirmed by ab initio molecular dynamics (AIMD) simulations which find that ~1 nm Rh and Ir particles (50-atom cluster) bind strongly to the MgAl2O4 surfaces via a redox process leading to a strong metal-support interaction, thus helping anchor the metal clusters and reduce the tendency to sinter. Density functional theory (DFT) calculations suggest that these supported smaller Rh and Ir particles have a lower work function than larger more bulk-like ones, which enables them to activate both water and methane more effectively than larger particles, yet have a minimal influence on the relative stability of coke precursors. In addition, theoretical mechanistic studies were used to probe the relationship between structure and reactivity. Consistent with the experimental observations, our theoretical modeling results also suggest that the small spinel-supported Ir particle catalyst is more active than the counterpart of Rh catalyst for SMR. This work was financially supported by the

  17. PERSPECTIVE: Low solar activity is blamed for winter chill over Europe

    NASA Astrophysics Data System (ADS)

    Benestad, Rasmus E.

    2010-06-01

    the direct effect from changes in the solar brightness (0.1%) was estimated to be too low to explain the temperature changes on Earth. The solar influence on changes in the global mean temperature has so far been found to be weak (Lean 2010, Benestad and Schmidt 2009). The important difference between recent and early studies is, however, that the latter lacked a theoretical framework based on physical mechanisms. Now we understand that stratospheric conditions vary, and are affected by chemical reactions as well as the absorption of UV light. Furthermore, we know that such variations affect temperature profiles, wave propagations, and winds (Schindell et al 2001). Lean (2010) and Haigh (2003) provide nice reviews of recent progress on solar-terrestrial relationships, although questions regarding the quality of the oldest solar data records are still unanswered (Benestad 2005). All these studies still rely on empirical data analysis. Much of the focus of the recent work has been on climate variation on global scales. The recent paper by Lockwood et al (2010) represents current progress, albeit that they emphasize that the relationship they identify has a regional rather than global character. Indeed, they stress that a change in the global mean temperature should not be confused with regional and seasonal means. The physical picture they provide is plausible, yet empirical relationships between solar activity and any of the indices describing the north Atlantic oscillation, the Arctic oscillation or the polar vortex are regarded as weak. My impression is nevertheless that the explanation provided by the Lockwood et al (2010) study reflects real aspects of our climate, especially if the effect is asymmetric. They argue that solar-induced changes in the stratosphere in turn affect the occurrence of persistent wintertime blocking. But one comprehensive, definite, consistent, and convincing documentation of the entire chain causality is still not in place, due to the lack

  18. The effects of copper doping on photocatalytic activity at (101) planes of anatase TiO2: A theoretical study

    NASA Astrophysics Data System (ADS)

    Assadi, M. Hussein N.; Hanaor, Dorian A. H.

    2016-11-01

    Copper dopants are varyingly reported to enhance photocatalytic activity at titanium dioxide surfaces through uncertain mechanisms. In order to interpret how copper doping might alter the performance of titanium dioxide photocatalysts in aqueous media we applied density functional theory methods to simulate surface units of doped anatase (101) planes. By including van der Waals interactions, we consider the energetics of adsorbed water at anatase surfaces in pristine and copper doped systems. Simulation results indicate that copper dopant at anatase (101) surfaces is most stable in a 2+ oxidation state and a disperse configuration, suggesting the formation of secondary CuO phases is energetically unfavourable. In agreement with previous reports, water at the studied surface is predicted to exhibit molecular adsorption with this tendency slightly enhanced by copper. Results imply that the enhancement of photoactivity at anatase surfaces through Cu doping is more likely to arise from electronic interactions mediated by charge transfer and inter-bandgap states increasing photoexcitation and extending surface-hole lifetimes rather than through the increased density of adsorbed hydroxyl groups.

  19. Synthesis, crystal structure and theoretical analysis of intermolecular interactions in two biologically active derivatives of 1,2,4-triazoles

    NASA Astrophysics Data System (ADS)

    Shukla, Rahul; Mohan, T. P.; Vishalakshi, B.; Chopra, Deepak

    2017-04-01

    In the present study, we have synthesized and structurally characterized two biologically active derivatives of 1,2,4 triazoles, namely 3-(4-fluoro-3-phenoxyphenyl)-1-(piperidin-1-ylmethyl)-1H-1,2,4-triazole-5(4H)-thione (TR) and 1-((3-(4-fluoro-3-phenoxyphenyl)-5-(methylthio)-1H-1,2,4-triazol-1-yl)methyl)piperidine (TR1) via single crystal X-ray diffraction. Both the structures show the presence of various intermolecular interactions in the crystalline solid such as Csbnd H…F, Csbnd H…S, Csbnd H…N, Csbnd H…O, Csbnd H … π, and π … π intermolecular interactions. The role of these interactions in molecular packing was analyzed, and the nature of these interactions was evaluated through computational procedures using PIXEL. Hirshfeld analysis further reveals that the contribution of H…F interactions was more prominent towards packing as compared to H…N/O intermolecular interactions.

  20. Size-dependent selectivity and activity of silver nanoclusters in the partial oxidation of propylene to propylene oxide and acrolein : A joint experimental and theoretical study.

    SciTech Connect

    Molina, L M.; Lee, S.; Sell, K.; Barcaro, G.; Fortunelli, A.; Lee, B.; Seifert, S.; Winans, R. E.; Elam, J. W.; Pellin, M. J.; Barke, I.; von Oeynhausen, V.; Lei, Y.; Meyer, R. J.; Alonso, J. A.; Fraile-Rodriguez, A.; Kleibert, A.; Giorgio, S.; Henry, C. R.; Heinz Meiwes-Broer, K.; Vadja, S.; Univ. de Valladolid; Univ. Rostock; IPCF-CNR; Univ. of Illinois at Chicago; Swiss Light Source; CINaM-CNRS and Aix-Marseille Univ.; Yale Univ.

    2011-02-02

    Model silver nanocatalysts between 9 and 23 nm in size were prepared by size-selected cluster deposition from a free cluster beam on amorphous alumina films and their size-dependent catalytic performance studied in the partial oxidation of propylene under realistic reaction conditions. Smaller clusters preferentially produced acrolein, while the 23 nm particles were considerably more selective towards the formation of propylene oxide, at reaction rates far exceeding those previously reported for larger silver particles. The activity of clusters dropped significantly with increasing particle size. First-principle calculations, of the activation energies for oxygen adsorption and its dissociation, at variable surface coverage yielded surface energies which resulted in particle shapes resembling the experimentally observed shapes of partially oxidized silver clusters. The calculated activation barriers for propylene oxide and acrolein formation on various facets and on the edges of the nanoparticles provided detailed information about the energetics of the competing reaction pathways. The size- and corresponding morphology dependent theoretical activity and selectivity are in good accord with experimental observations.

  1. Theoretical modelling of X-ray fluorescence signals for different lunar compositions and dependence on solar activity

    NASA Astrophysics Data System (ADS)

    Banerjee, D.; Vadawale, S.

    2010-09-01

    We present a forward modelling technique for calculating the surface X-ray spectra for a variety of lunar terrains. Our calculations considered variations in solar fluxes from solar quiescent condition to large flare activity (M1 flare), and expected elemental concentrations in the target, as well as yield, instrumental, and viewing geometry parameters for X-ray induced fluorescence from the lunar surface. Additionally, we present estimates of anticipated XRF signals from prominent K α lines observable by a collimated 14 cm 2 X-ray detector from a 100 km lunar orbit with ˜20 km spatial resolution. Our results show that Mg, Al and Si characteristic K α lines can be observed for all solar conditions. The Ca K α lines line can be differentiated from a fixed background during more energetic solar conditions such as C1 and M1 flares, whereas Ti and Fe lines are identifiable only during C1 and M1 solar flare conditions for Apollo 12 site composition. Both the K α X-ray intensity ratios of Mg/Si and Al/Si correlate well with concentration ratios of Mg/Si and Al/Si, respectively, for B1 and M1 solar conditions. The K α X-ray intensity ratios of Fe/Si and Ca/Si correlates with concentration ratios of Fe/Si and Ca/Si, respectively, for M1 solar condition. In principle, the modelling technique outlined here can be used to determine absolute elemental abundances (Mg, Al, Si, Ca, Ti and Fe) from X-ray spectra measured during recent and future lunar missions.

  2. Physical Activity Status and Position of Governmental Employees in Changing Stage Based on the Trans-Theoretical Model in Hamadan, Iran

    PubMed Central

    Abdi, Jalal; Eftekhar, Hassan; Mahmoodi, Mahmood; Shojayzadeh, Davood; Sadeghi, Roya

    2015-01-01

    Physical inactivity is the fourth leading risk factor for death worldwide. Given the key role of employees as valuable human resources and increasing sedentary life style among them, the aim of this study was to evaluate physical activity status and position of governmental employees in changing stage based on the Trans-Theoretical Model (TTM) in Hamadan, Iran, in 2014. This descriptive-analytical study was performed on 1200 government employees selected using proportional stratified random sampling. Data collection was performed using a three-section questionnaire containing demographic characteristics, SQUASH (Short questionnaire to assess health-enhancing physical activity) questionnaire and Marcus et al’s five-part algoritm. Data were analyzed by multiple linear and logistic regression, Chi-square, T-test and ANOVA using SPSS-20. The mean age of the participants was 38.12±8.04 years. About a half of the employees were in the preparatory stage of TTM.49.2% and 50.8% of the sample were classified as active and inactive, respectively. Associations between physical activity status and exercise stage of change were found. The associations between exercise stage of change and age, sex, work experience, education and marital status were significant (p<0.05). Work experience and education were strongly predictors of physical activity (PA) status and accounted for 31.2% of variance in PA (adjusted R2=0.312, R2 change=0.01). The results of this study showed that TTM was useful to evaluate and predict physical activity behavior among the Iranian governmental employees and can be utilized by health planners to inform appropriate intervention strategies, specifically in work place. PMID:26156899

  3. Theoretical predictions

    NASA Technical Reports Server (NTRS)

    Brasseur, G.; Boville, B. A.; Bruhl, C.; Caldwell, M.; Connell, Peter S.; Derudder, A.; Douglas, A.; Dyominov, I.; Fisher, D.; Frederick, J. F.

    1990-01-01

    In order to understand the impact of man made chemicals on the atmospheric ozone layer, it is essential to develop models that can perform long term predictions of future ozone changes. An advantage of using two dimensional models is that they can be used to predict latitudinal and seasonal changes in ozone. The formulation and recent improvements are described in 2-D models, which are used herein, along with the three dimensional models that are currently being developed to better simulate transport of chemically active trace gases, especially in polar regions. The range in 2-D model calculations is described. Selected fields calculated by these models are compared with observations. A number of scenarios have been defined, which encompass possible emission rates of different halocarbons. Because of the large uncertainties in the rates for heterogeneous processes, the calculated responses of the models include only the effects of homogeneous chemistry. One important distinction among the models is their ability to account for temperature feedbacks on the calculated ozone changes.

  4. The Educational Value of High Risk Activities in the Physical Education Program: A Social Philosophical Perspective.

    ERIC Educational Resources Information Center

    Sparks, Robert E. C.

    A growing number of schools and institutions in North America have begun offering training in high risk activities such as high element rope courses, rock climbing, white water kayaking and canoeing, and scuba diving in conjunction with their regular physical education activity programs. High risk activities are those activities which occur in or…

  5. A Matter of Perspective

    DTIC Science & Technology

    2012-04-21

    OUTCOMES. Based on the theoretical work of Jean Piaget and George Herbert Mead regarding perspective-taking capability enabling non-egocentric...discussion and comparison of theories and models of Piaget , Lawrence Kohlberg and Robert Selman, see Joseph Anthony Rodriguez’ dissertation, ―The...Development: A Sullivan- Piaget Perspective, Phoenix ed. (University of Chicago Press, 1982), 9. 27 Perrine Ruby and Jean Decety, ―How Would You Feel Versus

  6. Cationic (V, Y)-codoped TiO2 with enhanced visible light induced photocatalytic activity: A combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Khan, Matiullah; Cao, Wenbin

    2013-11-01

    To employ TiO2 as an efficient photocatalyst, high reactivity under visible light and improved separation of photoexcited carriers are required. An effective co-doping approach is applied to modify the photocatalytic properties of TiO2 by doping vanadium (transition metal) and yttrium (rare earth element). V and/or Y codoped TiO2 was prepared using hydrothermal method without any post calcination for crystallization. Based on density functional theory, compensated and noncompensated V, Y codoped TiO2 models were constructed and their structural, electronic, and optical properties were calculated. Through combined experimental characterization and theoretical modeling, V, Y codoped TiO2 exhibited high absorption coefficient with enhanced visible light absorption. All the prepared samples showed pure anatase phase and spherical morphology with uniform particle distribution. Electronic band structure demonstrates that V, Y codoping drastically reduced the band gap of TiO2. It is found that both the doped V and Y exist in the form of substitutional point defects replacing Ti atom in the lattice. The photocatalytic activity, evaluated by the degradation of methyl orange, displays that the codoped TiO2 sample exhibits enhanced visible light photocatalytic activity. The synergistic effects of V and Y drastically improved the Brunauer-Emmett-Teller specific surface area, visible light absorption, and electron-hole pair's separation leading to the enhanced visible light catalytic activity.

  7. Cationic (V, Y)-codoped TiO{sub 2} with enhanced visible light induced photocatalytic activity: A combined experimental and theoretical study

    SciTech Connect

    Khan, Matiullah E-mail: wbcao@ustb.edu.cn; Cao, Wenbin E-mail: wbcao@ustb.edu.cn

    2013-11-14

    To employ TiO{sub 2} as an efficient photocatalyst, high reactivity under visible light and improved separation of photoexcited carriers are required. An effective co-doping approach is applied to modify the photocatalytic properties of TiO{sub 2} by doping vanadium (transition metal) and yttrium (rare earth element). V and/or Y codoped TiO{sub 2} was prepared using hydrothermal method without any post calcination for crystallization. Based on density functional theory, compensated and noncompensated V, Y codoped TiO{sub 2} models were constructed and their structural, electronic, and optical properties were calculated. Through combined experimental characterization and theoretical modeling, V, Y codoped TiO{sub 2} exhibited high absorption coefficient with enhanced visible light absorption. All the prepared samples showed pure anatase phase and spherical morphology with uniform particle distribution. Electronic band structure demonstrates that V, Y codoping drastically reduced the band gap of TiO{sub 2}. It is found that both the doped V and Y exist in the form of substitutional point defects replacing Ti atom in the lattice. The photocatalytic activity, evaluated by the degradation of methyl orange, displays that the codoped TiO{sub 2} sample exhibits enhanced visible light photocatalytic activity. The synergistic effects of V and Y drastically improved the Brunauer-Emmett-Teller specific surface area, visible light absorption, and electron-hole pair's separation leading to the enhanced visible light catalytic activity.

  8. Self, College Experiences, and Society: Rethinking the Theoretical Foundations of Student Development Theory

    ERIC Educational Resources Information Center

    Winkle-Wagner, Rachelle

    2012-01-01

    This article examines the psychological theoretical foundations of college student development theory and the theoretical assumptions of this framework. A complimentary, sociological perspective and the theoretical assumptions of this approach are offered. The potential limitations of the overuse of each perspective are considered. The conclusion…

  9. Reconciling cognitive and affective neuroscience perspectives on the brain basis of emotional experience.

    PubMed

    Panksepp, Jaak; Lane, Richard D; Solms, Mark; Smith, Ryan

    2016-09-15

    The "affective" and "cognitive" neuroscience approaches to understanding emotion (AN and CN, respectively) represent potentially synergistic, but as yet unreconciled, theoretical perspectives, which may in part stem from the methods that these distinct perspectives routinely employ-one focusing on animal brain emotional systems (AN) and one on diverse human experimental approaches (CN). Here we present an exchange in which each approach (1) describes its own theoretical perspective, (2) offers a critique of the other perspective, and then (3) responds to each other's critique. We end with a summary of points of agreement and disagreement, and describe possible future experiments that could help resolve the remaining controversies. Future work should (i) further characterize the structure/function of subcortical circuitry with respect to its role in generating emotion, and (ii) further investigate whether sub-neocortical activations alone are sufficient (as opposed to merely necessary) for affective experiences, or whether subsequent cortical representation of an emotional response is also required.

  10. Looking from a CHAT-IT Perspective to Undergraduate Mexican Physics: Organizational Trajectories or Professors as Agents of Change?

    ERIC Educational Resources Information Center

    Kahveci, Ajda

    2010-01-01

    Recent elaborations on cultural-historical activity theory (CHAT) (Engestrom et al., eds., "Perspectives on activity theory." New York: Cambridge University Press, "1999") and its relation to organizational theories have produced a theoretical amalgam of these earlier ideas, which allow for the exploration of learning in formal…

  11. Theoretical Foundations of Active Learning

    DTIC Science & Technology

    2009-05-01

    most interesting hypothesis classes, this is known to be NP-Hard – though interestingly, there are some efficient special cases [e.g., 48 Kalai ...learnable at an exponential rate [e.g., Balcan, Broder, and Zhang, 2007, Dasgupta, 2005, Dasgupta, Kalai , and Monteleoni, 2005, Hanneke, 2007b] combined...Systems 18, 2005. 1.6, 1.6, 3.1, 3.2, 3.2.1, 3.2.2, 3.4, 3.5.2, 3.6, 3.10, 5.3.1, 5.4 S. Dasgupta, A. Kalai , and C. Monteleoni. Analysis of perceptron

  12. Do time perspective and sensation-seeking predict quitting activity among smokers? Findings from the International Tobacco Control (ITC) Four Country Survey.

    PubMed

    Hall, Peter A; Fong, Geoffrey T; Yong, Hua-Hie; Sansone, Genevieve; Borland, Ron; Siahpush, Mohammad

    2012-12-01

    Personality factors such as time perspective and sensation-seeking have been shown to predict smoking uptake. However, little is known about the influences of these variables on quitting behavior, and no prior studies have examined the association cross-nationally in a large probability sample. In the current study it was hypothesized that future time perspective would enhance - while sensation-seeking would inhibit - quitting activity among smokers. It was anticipated that the effects would be similar across English speaking countries. Using a prospective cohort design, this cross-national study of adult smokers (N=8845) examined the associations among time perspective, sensation-seeking and quitting activity using the first three waves of data gathered from the International Tobacco Control Four Country Survey (ITC-4), a random digit dialed telephone survey of adult smokers from the United Kingdom, United States, Canada and Australia. Findings revealed that future time perspective (but not sensation-seeking) was a significant predictor of quitting attempts over the 8-month follow-up after adjusting for socio-demographic variables, factors known to inhibit quitting (e.g., perceived addiction, enjoyment of smoking, and perceived value of smoking), and factors known to enhance quitting (e.g., quit intention strength, perceived benefit of quitting, concerns about health effects of smoking). The latter, particularly intention, were significant mediators of the effect of time perspective on quitting activity. The effects of time perspective on quitting activity were similar across all four English speaking countries sampled. If these associations are causal in nature, it may be the case that interventions and health communications that enhance future-orientation may foster more quit attempts among current smokers.

  13. Perspectives on Physical Activity Among People with Multiple Sclerosis Who Are Wheelchair Users

    PubMed Central

    Learmonth, Yvonne C.; Rice, Ian M.; Ostler, Teresa; Rice, Laura A.

    2015-01-01

    Background: People with advanced multiple sclerosis (MS) are less physically active than those with milder forms of the disease, and wheelchair use has a negative association with physical activity participation. Thus, wheelchair users with MS are doubly disadvantaged for accruing the benefits of physical activity and exercise. Appropriate physical activity and exercise interventions are needed for this population. Methods: We undertook a qualitative study to explore the meanings, motivations, and outcomes of physical activity in wheelchair users with MS. We sought to understand daily opportunities to accumulate physical activity and exercise, and to identify perceived barriers, facilitators, and benefits that might inform the design of future interventions. Results: We interviewed 15 wheelchair users (mean age, 52 ± 8.8 years; n = 12 women). Data were transcribed and analyzed to identify and explore common themes. Our first theme was the reduced opportunity to participate in physical activity due to participants' dependence on mobility devices, environmental adaptations, and tangible support. Our second theme was the importance of incorporating physical activity and exercise into the everyday environment, highlighting the need for adaptive exercise and accessible environments. This indicated the need to incorporate behavior change modulators into physical activity and exercise interventions for those with advanced MS. Health-care professionals played an important role in promoting increased physical activity and exercise participation in those with advanced MS. Conclusions: Our findings may inform future interventions to increase initiation and maintenance of physical activity and exercise among people with advanced MS. PMID:26052256

  14. Expanded Perspectives on Autonomous Learners

    ERIC Educational Resources Information Center

    Oxford, Rebecca L.

    2015-01-01

    This paper explores two general perspectives on autonomous learners: psychological and sociocultural. These perspectives introduce a range of theoretically grounded facets of autonomous learners, facets such as the self-regulated learner, the emotionally intelligent learner, the self-determined learner, the mediated learner, the socioculturally…

  15. The Role of Female Teachers in Activating Effective Teaching Skills and Methods among High School Students from the Teachers' Perspective--Najran, KSA

    ERIC Educational Resources Information Center

    Wahsheh, Rula; Alhawamdeh, Haifa

    2015-01-01

    The study aimed to identify the role of female teachers in activating effective teaching skills and methods among high school students from the teachers' perspective--Najran, KSA. The researcher used the descriptive analytical approach. Instrument of the study is a questionnaire with (76) items distributing to (3) domains: the first domain is…

  16. Culture, Learning, and Development and the Natural World: The Influences of Situative Perspectives

    ERIC Educational Resources Information Center

    Bang, Megan

    2015-01-01

    The study of human learning and development from situative or sociocultural perspectives has had significant impacts on a wide range of scholarship largely driven by the theoretical and methodological focus on understanding the role of "activity systems" in cognition and development. This article first explores how situative perspectives…

  17. Perspectives Do Matter: "Joint Screen", a Promising Methodology for Multimodal Interaction Analysis

    ERIC Educational Resources Information Center

    Arend, Béatrice; Sunnen, Patrick; Fixmer, Pierre; Sujbert, Monika

    2014-01-01

    This paper discusses theoretical and methodological issues arising from a video-based research design and the emergent tool "Joint Screen'"when grasping joint activity. We share our reflections regarding the combined reading of four synchronised camera perspectives combined in one screen. By these means we reconstruct and analyse…

  18. Problems and Perspectives on the Evaluation of Regional and National Computer-Related Educational Activity.

    ERIC Educational Resources Information Center

    Collis, Betty

    Although the importance of systematic evaluation of educational policy and practice is well established, various problems confound the intention of evaluating regional or national activity with regard to computer-related activities in education. At least two of these problems relate to a general conception of the appropriate entry points for…

  19. Participation or Exclusion? Perspectives of Pupils with Autistic Spectrum Disorders on Their Participation in Leisure Activities

    ERIC Educational Resources Information Center

    Brewster, Stephanie; Coleyshaw, Liz

    2011-01-01

    The importance of active participation in leisure activities for everybody is identified by Carr (2004) but issues around leisure in the lives of children with disabilities have received little recognition. The experience of children/young people (henceforth referred to simply as children, for brevity) with autistic spectrum disorders (ASD) in…

  20. Parent Perspectives of Participation in Home and Community Activities when Receiving Part C Early Intervention Services

    ERIC Educational Resources Information Center

    Khetani, Mary A.; Cohn, Ellen S.; Orsmond, Gael I.; Law, Mary C.; Coster, Wendy J.

    2013-01-01

    The authors examined the extent to which parent expectations, perceptions about resource availability and supports, and strategies used to promote participation in home and community activities varied by setting and activity type. Sixteen 90-min semistructured interviews were completed with families receiving Part C early intervention services in…

  1. "Active Living" Related to the Rural-Urban Continuum: A Time-Use Perspective

    ERIC Educational Resources Information Center

    Millward, Hugh; Spinney, Jamie

    2011-01-01

    Purpose: This paper assesses the degree to which "active living" varies along the rural-urban continuum, within the county-sized regional municipality of Halifax, Nova Scotia. Methods: Time-diary data from the Halifax Space-Time Activity Research project were used to compute daily participation rates (PRs) and time durations, at various…

  2. A Social Cognitive Perspective of Physical-Activity-Related Behavior in Physical Education

    ERIC Educational Resources Information Center

    Martin, Jeffrey J.; Kulinna, Pamela Hodges

    2005-01-01

    The purpose of the current study was to examine student and teacher physical-activity-related behavior using the theory of planned behavior and self-efficacy theory. Although teachers reported an overwhelmingly positive attitude toward teaching physical activity lessons to promote fitness development, they only devoted 4% of their class time to…

  3. A Philosophical Perspective on Leading Music Activities for the Over 50s

    ERIC Educational Resources Information Center

    McQueen, Hilary; Hallam, Susan; Creech, Andrea; Varvarigou, Maria

    2013-01-01

    The basis of this article is findings from the Music for Life Project which investigated the benefits and challenges of music activity participation for the over 50s in three case study sites in the United Kingdom. The paper uses a philosophical lens to explore the leaders' and participants' views on the purpose of the activities, how learners are…

  4. Exploration of Tensions in a Mobile-Technology Supported Fieldtrip: An Activity Theory Perspective

    ERIC Educational Resources Information Center

    Lai, Chih-Hung; Chen, Fei-Ching; Yang, Jie-Chi

    2014-01-01

    The purpose of this study was to analyze how mobile technologies were incorporated and implemented in an outdoor learning activity. Two classes of primary school students participated in the experiment. Using activity theory as an analytical framework, it is found that underlying tensions provided rich insights into system dynamics and that…

  5. An Active Learning Exercise for Product Design from an Operations Perspective

    ERIC Educational Resources Information Center

    Hill, Stephen; Baker, Elizabeth

    2016-01-01

    Product design is a topic that is regularly covered in introductory operations management courses. However, a pedagogical challenge exists related to the presentation of introductory-level product design in a way that promotes active learning. The hands-on exercise presented in this article provides instructors with an activity that gives students…

  6. Theoretical insights into interprofessional education.

    PubMed

    Hean, Sarah; Craddock, Deborah; Hammick, Marilyn

    2012-01-01

    This article argues for the need for theory in the practice of interprofessional education. It highlights the range of theories available to interprofessional educators and promotes the practical application of these to interprofessional learning and teaching. It summarises the AMEE Guides in Medical Education publication entitled Theoretical Insights into Interprofessional Education: AMEE Guide No. 62, where the practical application of three theories, social capital, social constructivism and a sociological perspective of interprofessional education are discussed in-depth through the lens of a case study. The key conclusions of these discussions are presented in this article.

  7. Some thoughts on theoretical physics

    NASA Astrophysics Data System (ADS)

    Tsallis, Constantino

    2004-12-01

    Some thoughts are presented on the inter-relation between beauty and truth in science in general and theoretical physics in particular. Some conjectural procedures that can be used to create new ideas, concepts and results are illustrated in both Boltzmann-Gibbs and nonextensive statistical mechanics. The sociological components of scientific progress and its unavoidable and benefic controversies are, mainly through existing literary texts, briefly addressed as well. Short essay based on the plenary talk given at the International Workshop on Trends and Perspectives in Extensive and Non-Extensive Statistical Mechanics, held in November 19-21, 2003, in Angra dos Reis, Brazil.

  8. Active Control of Fan Noise: Feasibility Study. Volume 6; Theoretical Analysis for Coupling of Active Noise Control Actuator Ring Sources to an Annular Duct with Flow

    NASA Technical Reports Server (NTRS)

    Kraft, R. E.

    1996-01-01

    The objective of this effort is to develop an analytical model for the coupling of active noise control (ANC) piston-type actuators that are mounted flush to the inner and outer walls of an annular duct to the modes in the duct generated by the actuator motion. The analysis will be used to couple the ANC actuators to the modal analysis propagation computer program for the annular duct, to predict the effects of active suppression of fan-generated engine noise sources. This combined program will then be available to assist in the design or evaluation of ANC systems in fan engine annular exhaust ducts. An analysis has been developed to predict the modes generated in an annular duct due to the coupling of flush-mounted ring actuators on the inner and outer walls of the duct. The analysis has been combined with a previous analysis for the coupling of modes to a cylindrical duct in a FORTRAN computer program to perform the computations. The method includes the effects of uniform mean flow in the duct. The program can be used for design or evaluation purposes for active noise control hardware for turbofan engines. Predictions for some sample cases modeled after the geometry of the NASA Lewis ANC Fan indicate very efficient coupling in both the inlet and exhaust ducts for the m = 6 spinning mode at frequencies where only a single radial mode is cut-on. Radial mode content in higher order cut-off modes at the source plane and the required actuator displacement amplitude to achieve 110 dB SPL levels in the desired mode were predicted. Equivalent cases with and without flow were examined for the cylindrical and annular geometry, and little difference was found for a duct flow Mach number of 0.1. The actuator ring coupling program will be adapted as a subroutine to the cylindrical duct modal analysis and the exhaust duct modal analysis. This will allow the fan source to be defined in terms of characteristic modes at the fan source plane and predict the propagation to the

  9. Poverty and Delinquency: A Theoretical Review.

    ERIC Educational Resources Information Center

    Rodman, Hyman

    One of 52 theoretical papers on school crime and its relation to poverty, this chapter reviews the major cultural and structural statements on the relationship between poverty and delinquency. The value stretch perspective, stemming from research on family values and on aspirations is introduced in order to challenge and clarify the basic works of…

  10. A Review of Theoretical and Empirical Advancements

    ERIC Educational Resources Information Center

    Wang, Mo; Henkens, Kene; van Solinge, Hanna

    2011-01-01

    In this article, we review both theoretical and empirical advancements in retirement adjustment research. After reviewing and integrating current theories about retirement adjustment, we propose a resource-based dynamic perspective to apply to the understanding of retirement adjustment. We then review empirical findings that are associated with…

  11. Masochism: a clinical and theoretical overview.

    PubMed

    Sack, R L; Miller, W

    1975-08-01

    This paper will review some of the theoretical and clinical features of masochism from an eclectic point of view. The topic of masochism has been taken up by authors of many perspectives because it addresses one of the anomalous, absurd, difficult-to-explain aspects of behavior for which no psychological system has an easy answer. Therefore, a wide-ranging literature on the topic of masochism is available. However, few previous reviewers have attempted to draw from a variety of disciplines and theoretical frameworks. In this review the historical development of the term and some of the psychoanalytic conceptualizations will be presented first. Since previous reviews of masochism from a strictly psychoanalytic perspective are adequate (Brenner, 1959; Eisenbud, 1967; Fenichel, 1945; Loewenstein, 1957; Panken, 1967), our discussions of masochism will be developed employing more extensively the interpersonal, social, learning theory, and biological perspectives.

  12. The impact of National Guard activation for homeland defense: employers' perspective.

    PubMed

    Allison-Aipa, Timothy S; De La Rosa, Gabriel M; Stetz, Melba C; Castro, Carl A

    2005-10-01

    Data gathered from a study of reserve component (RC) soldiers who were activated during the spring of 2002, following the terrorist attacks of September 11, 2001, suggested that they were concerned about how the effects of their activation affected their civilian employment. Therefore, the purpose of this study was to obtain this information from the civilian employers of these RC soldiers. Most civilian employers who participated in this study (N = 28) were male (89%) and working in law enforcement (39%). Fifty-six percent of employers gave consent to be interviewed by telephone. Although supervisors reported difficulties in several areas of operation and aspects of the RC activation, they still supported the activation of their RC employees and their military mission. This study is a significant start to illuminating the important roles that both RC employees and their civilian employers play in homeland defense.

  13. Antimicrobial activity of Antarctic bryozoans: an ecological perspective with potential for clinical applications.

    PubMed

    Figuerola, Blanca; Sala-Comorera, Laura; Angulo-Preckler, Carlos; Vázquez, Jennifer; Jesús Montes, M; García-Aljaro, Cristina; Mercadé, Elena; Blanch, Anicet R; Avila, Conxita

    2014-10-01

    The antimicrobial activity of Antarctic bryozoans and the ecological functions of the chemical compounds involved remain largely unknown. To determine the significant ecological and applied antimicrobial effects, 16 ether and 16 butanol extracts obtained from 13 different bryozoan species were tested against six Antarctic (including Psychrobacter luti, Shewanella livingstonensis and 4 new isolated strains) and two bacterial strains from culture collections (Escherichia coli and Bacillus cereus). Results from the bioassays reveal that all ether extracts exhibited antimicrobial activity against some bacteria. Only one butanol extract produced inhibition, indicating that antimicrobial compounds are mainly lipophilic. Ether extracts of the genus Camptoplites inhibited the majority of bacterial strains, thus indicating a broad-spectrum of antimicrobial activity. Moreover, most ether extracts presented activities against bacterial strains from culture collections, suggesting the potential use of these extracts as antimicrobial drugs against pathogenic bacteria.

  14. Current perspectives on physical activity and exercise for youth with diabetes.

    PubMed

    Pivovarov, Jacklyn A; Taplin, Craig E; Riddell, Michael C

    2015-06-01

    Regular physical activity (PA) for youth with diabetes improves cardiorespiratory fitness, body composition, bone health, insulin sensitivity, and psychosocial well-being. However many youth with diabetes or pre-diabetes fail to meet minimum PA guidelines and a large percentage of youth with diabetes are overweight or obese. Active youth with type 1 diabetes tend to have lower HbA1c levels and reduced insulin needs, whereas activity in adolescents at-risk for type 2 diabetes improves various measures of metabolism and body composition. Insulin and nutrient adjustments for exercise in type 1 diabetes is complex because of varied responses to exercise type and because of the different times of day that exercise is performed. This review highlights the benefits of exercise and the established barriers to exercise participation in the pediatric diabetes population. A new exercise management algorithm for insulin and carbohydrate intake strategies for active youth with type 1 diabetes is presented.

  15. Understanding the challenges to facilitating active learning in the resident conferences: a qualitative study of internal medicine faculty and resident perspectives.

    PubMed

    Sawatsky, Adam P; Zickmund, Susan L; Berlacher, Kathryn; Lesky, Dan; Granieri, Rosanne

    2015-01-01

    Background In the Next Accreditation System, the Accreditation Council for Graduate Medical Education outlines milestones for medical knowledge and requires regular didactic sessions in residency training. There are many challenges to facilitating active learning in resident conferences, and we need to better understand resident learning preferences and faculty perspectives on facilitating active learning. The goal of this study was to identify challenges to facilitating active learning in resident conferences, both through identifying specific implementation barriers and identifying differences in perspective between faculty and residents on effective teaching and learning strategies. Methods The investigators invited core residency faculty to participate in focus groups. The investigators used a semistructured guide to facilitate discussion about learning preferences and teaching perspectives in the conference setting and used an 'editing approach' within a grounded theory framework to qualitative analysis to code the transcripts and analyze the results. Data were compared to previously collected data from seven resident focus groups. Results Three focus groups with 20 core faculty were conducted. We identified three domains pertaining to facilitating active learning in resident conferences: barriers to facilitating active learning formats, similarities and differences in faculty and resident learning preferences, and divergence between faculty and resident opinions about effective teaching strategies. Faculty identified several setting, faculty, and resident barriers to facilitating active learning in resident conferences. When compared to residents, faculty expressed similar learning preferences; the main differences were in motivations for conference attendance and type of content. Resident preferences and faculty perspectives differed on the amount of information appropriate for lecture and the role of active participation in resident conferences. Conclusion

  16. From body art to anticancer activities: perspectives on medicinal properties of henna.

    PubMed

    Pradhan, Rohan; Dandawate, Prasad; Vyas, Alok; Padhye, Subhash; Biersack, Bernhard; Schobert, Rainer; Ahmad, Aamir; Sarkar, Fazlul H

    2012-12-01

    Nature has been a rich source of therapeutic agents for thousands of years and an impressive number of modern drugs have been isolated from natural sources based on the uses of these plants in traditional medicine. Henna is one such plant commonly known as Persian Henna or Lawsonia inermis, a bushy, flowering tree, commonly found in Australia, Asia and along the Mediterranean coasts of Africa. Paste made from the leaves of Henna plant has been used since the Bronze Age to dye skin, hairs and fingernails especially at the times of festivals. In recent times henna paste has been used for body art paintings and designs in western countries. Despite such widespread use in dyeing and body art painting, Henna extracts and constituents possess numerous biological activities including antioxidant, anti-inflammatory, antibacterial and anticancer activities. The active coloring and biologically active principle of Henna is found to be Lawsone (2- hydroxy-1, 4-naphthoquinone) which can serve as a starting building block for synthesizing large number of therapeutically useful compounds including Atovaquone, Lapachol and Dichloroallyl lawsone which have been shown to possess potent anticancer activities. Some other analogs of Lawsone have been found to exhibit other beneficial biological properties such as antioxidant, anti-inflammatory, antitubercular and antimalarial. The ability of Lawsone to undergo the redox cycling and chelation of trace metal ions has been thought to be partially responsible for some of its biological activities. Despite such diverse biological properties and potent anticancer activities the compound has remained largely unexplored and hence in the present review we have summarized the chemistry and biological activities of Lawsone along with its analogs and metal complexes.

  17. Perspectives on the development of novel potentially active quinolones against tuberculosis and cancer.

    PubMed

    Facchinetti, V; Gomes, C R B; de Souza, M V N; Vasconcelos, T R A

    2012-08-01

    Quinolones and its derivatives comprise an important group of heterocyclic compounds that exhibit a wide range of pharmacological properties such as antibacterial, antitumor, antiviral, anti-ischemic, antiparasitic and anxiolytic. Persistent efforts have been made over the years to develop novel congeners with superior biological activities and minimal potential for undesirable side-effects. The present review aims to highlight some recent discoveries on the development of novel quinolone-based compounds with potential antitubercular and anticancer activity.

  18. Physical activity in patients with venous leg ulcer – between engagement and avoidance. A patient perspective

    PubMed Central

    Biguet, Gabriele; Elfving, Britt

    2011-01-01

    Objective: To identify and describe the qualitative variations in how physical activity is perceived and understood by individuals with current or previous venous leg ulcer. Design: A qualitative study using semi-structured interviews. Method: Twenty-two individuals aged 60–85 years were interviewed. The interviews were recorded, transcribed verbatim and analysed by three researchers using a phenomenographic research approach. A set of categories of descriptions and their internal relationships were constructed based on the essential features of the variation in patients’ perceptions of physical activity. Results: Four categories of descriptions were identified: (i) ‘self-management’, (ii) ‘instructions and support’, (iii) ‘fear of injury’ and (iv) ‘a wish to stay normal’. The categories could be interpreted by a two-dimensional construct: (1) perception of venous leg ulcer as a chronic or acute condition and (2) engagement or avoidance behaviour toward physical activity. Chronicity and behaviour combined together formed a 2 × 2 square housing the four qualitatively different categories. Irrespective of category, the participants reported that information given by caregivers regarding leg ulcer and physical activity was insufficient or contradictory. Written information or exercise programmes were not obtained regularly and not at all in primary care. Conclusion: A dichotomous view emerged from participants’ experiences of physical activity based on (1) perception of venous leg ulcer as a chronic or acute condition and (2) engagement or avoidance behaviour toward physical activity. PMID:21148268

  19. Sixty minutes of what? A developing brain perspective for activating children with an integrative exercise approach.

    PubMed

    Myer, Gregory D; Faigenbaum, Avery D; Edwards, Nicholas M; Clark, Joseph F; Best, Thomas M; Sallis, Robert E

    2015-12-01

    Current recommendations for physical activity in children overlook the critical importance of motor skill acquisition early in life. Instead, they focus on the quantitative aspects of physical activity (eg, accumulate 60 min of daily moderate to vigorous physical activity) and selected health-related components of physical fitness (eg, aerobic fitness, muscular strength, muscular endurance, flexibility and body composition). This focus on exercise quantity in youth may limit considerations of qualitative aspects of programme design which include (1) skill development, (2) socialisation and (3) enjoyment of exercise. The timing of brain development and associated neuroplasticity for motor skill learning makes the preadolescence period a critical time to develop and reinforce fundamental movement skills in boys and girls. Children who do not participate regularly in structured motor skill-enriched activities during physical education classes or diverse youth sports programmes may never reach their genetic potential for motor skill control which underlies sustainable physical fitness later in life. The goals of this review are twofold: (1) challenge current dogma that is currently focused on the quantitative rather than qualitative aspects of physical activity recommendations for youth and (2) synthesise the latest evidence regarding the brain and motor control that will provide the foundation for integrative exercise programming that provide a framework sustainable activity for life.

  20. Revisiting the mechanism of coagulation factor XIII activation and regulation from a structure/functional perspective

    PubMed Central

    Gupta, Sneha; Biswas, Arijit; Akhter, Mohammad Suhail; Krettler, Christoph; Reinhart, Christoph; Dodt, Johannes; Reuter, Andreas; Philippou, Helen; Ivaskevicius, Vytautas; Oldenburg, Johannes

    2016-01-01

    The activation and regulation of coagulation Factor XIII (FXIII) protein has been the subject of active research for the past three decades. Although discrete evidence exists on various aspects of FXIII activation and regulation a combinatorial structure/functional view in this regard is lacking. In this study, we present results of a structure/function study of the functional chain of events for FXIII. Our study shows how subtle chronological submolecular changes within calcium binding sites can bring about the detailed transformation of the zymogenic FXIII to its activated form especially in the context of FXIIIA and FXIIIB subunit interactions. We demonstrate what aspects of FXIII are important for the stabilization (first calcium binding site) of its zymogenic form and the possible modes of deactivation (thrombin mediated secondary cleavage) of the activated form. Our study for the first time provides a structural outlook of the FXIIIA2B2 heterotetramer assembly, its association and dissociation. The FXIIIB subunits regulatory role in the overall process has also been elaborated upon. In summary, this study provides detailed structural insight into the mechanisms of FXIII activation and regulation that can be used as a template for the development of future highly specific therapeutic inhibitors targeting FXIII in pathological conditions like thrombosis. PMID:27453290

  1. Black Families. Interdisciplinary Perspectives.

    ERIC Educational Resources Information Center

    Cheatham, Harold E., Ed.; Stewart, James B., Ed.

    Since the early 1960s, the black family has been characterized as pathological. This six-part collection of 18 research studies presents alternative approaches to understanding the special characteristics of black families. Part I, "Theoretical and Methodological Perspectives," comprises a comparison of the pioneering work of W. E. B. Du…

  2. Institute for Theoretical Physics

    SciTech Connect

    Giddings, S.B.; Ooguri, H.; Peet, A.W.; Schwarz, J.H.

    1998-06-01

    String theory is the only serious candidate for a unified description of all known fundamental particles and interactions, including gravity, in a single theoretical framework. Over the past two years, activity in this subject has grown rapidly, thanks to dramatic advances in understanding the dynamics of supersymmetric field theories and string theories. The cornerstone of these new developments is the discovery of duality which relates apparently different string theories and transforms difficult strongly coupled problems of one theory into weakly coupled problems of another theory.

  3. Agreement Between pQCT- and DXA-Derived Indices of Bone Geometry, Density, and Theoretical Strength in Females of Varying Age, Maturity, and Physical Activity

    PubMed Central

    Dowthwaite, Jodi Noelle; Flowers, Portia PE; Scerpella, Tamara Ann

    2011-01-01

    Measurement of bone mass, geometry, density, and strength are critical in bone research and clinical studies. For peripheral quantitative computed tomography (pQCT), single and repeated measurements are particularly adversely affected by movement and positional variation. Dual-energy X-ray absorptiometry (DXA)–derived indices may alleviate these problems and provide useful alternative assessments. To evaluate this hypothesis, distal radius DXA and pQCT indices were compared in 101 healthy females aged 8.0 to 22.8 years (prepuberty to adulthood), reflecting a broad range of body sizes, physical maturity, and activity exposures. At the diaphysis, correlations were ρ =+0.74 to +0.98, with strong intermethod agreement for most indices. At the metaphysis, correlations were ρ =+0.64 to +0.97; intermethod agreement improved with modifications to the simplified geometric formulas more closely reflecting metaphyseal bone geometry. Further improvements may be possible because skeletal size and maturity-related biases in agreement were detected. Overall, DXA-derived indices may provide a useful assessment of bone geometry, density, and theoretical strength contingent on appropriate consideration of their limitations. PMID:21611973

  4. A theoretical model for {sup 222}Rn adsorption on activated charcoal canisters in humid air based on Polanyi`s potential theory

    SciTech Connect

    Scarpitta, S.C.

    1995-03-01

    Water vapor interferes with adsorption {sup 222}Rn gas by passive activated charcoal devices used to estimate indoor air concentrations. The {sup 222}Rn adsorption coefficient is the fundamental parameter characterizing charcoal`s ability to adsorb {sup 222}Rn. The Dubinin-Radushkevich equation, based on Polanyi`s potential theory, was modified to include two terms quantifying the effect of both water vapor and sampling time on the {sup 222}Rn adsorption coefficient of passive charcoal devices. A single equation was derived that quantities the {sup 222}Rn adsorption coefficients at any temperature, humidity and exposure time using six experimentally determined physical constants that are unique for a particular passive charcoal device. The theoretical model was verified with published experimental data, and it showed a good correlation between theory and experiment. The model proved to be consistent with experimental data, provided that the amount of water vapor adsorbed by the charcoal device during sampling remains below a critical level, termed the breakpoint. 44 refs., 5 figs., 2 tabs.

  5. Developer and Realtor Perspectives on Factors That Influence Development, Sale, and Perceived Demand for Activity-Friendly Communities

    PubMed Central

    Carnoske, Cheryl; Hoehner, Christine; Ruthmann, Nicholas; Frank, Lawrence; Handy, Susan; Hill, James; Ryan, Sherry; Sallis, James; Glanz, Karen; Brownson, Ross

    2013-01-01

    Background Although public support for physical activity-friendly Traditional Neighborhood Developments (TNDs) appears to be growing, information is lacking on private sector perspectives and how economic factors (eg, fuel prices) might influence the development and sale of TNDs. Methods A sample of realtors from the National Association of Realtors (n = 4950) and developers from the National Association of Home Builders (n = 162) were surveyed in early 2009 to assess factors influencing homebuyers’ decisions; incentives and barriers to developing TNDs; effects of depressed housing market conditions and financing on sales; trends in buying; and energy considerations (eg, green building). Results Realtors believed that homebuyers continue to rank affordability, safety and school quality higher than TND amenities. Developers reported numerous barriers to TNDs, including the inability to overcome governmental/political hurdles, lack of cooperation between government agencies, and lack of market demand. Yet, realtors believed clients are increasingly influenced by gas and oil prices, and developers reported that clients are looking for energy efficient homes, reduced commute time, and walkable neighborhoods. Respondents reported consumers are more interested in living in a TND than 5 years ago. Conclusions Activity-friendly TNDs appear to be increasing in demand, but developers and realtors reported significant barriers to creating these communities. PMID:20440012

  6. A synthetic ecology perspective: How well does behavior of model organisms in the laboratory predict microbial activities in natural habitats?

    SciTech Connect

    Yu, Zheng; Krause, Sascha M. B.; Beck, David A. C.; Chistoserdova, Ludmila

    2016-06-15

    In this perspective article, we question how well model organisms, the ones that are easy to cultivate in the laboratory and that show robust growth and biomass accumulation, reflect the dynamics and interactions of microbial communities observed in nature. Today's -omics toolbox allows assessing the genomic potential of microbes in natural environments in a high-throughput fashion and at a strain-level resolution. However, understanding of the details of microbial activities and of the mechanistic bases of community function still requires experimental validation in simplified and fully controlled systems such as synthetic communities. We have studied methane utilization in Lake Washington sediment for a few decades and have identified a number of species genetically equipped for this activity. We have also identified cooccurring satellite species that appear to form functional communities together with the methanotrophs. Here, we compare experimental findings from manipulation of natural communities involved in metabolism of methane in this niche with findings from manipulation of synthetic communities assembled in the laboratory of species originating from the same study site, from very simple (two-species) to rather complex (50-species) synthetic communities. We observe some common trends in community dynamics between the two types of communities, toward representation of specific functional guilds. However, we also identify strong discrepancies between the dominant methane oxidizers in synthetic communities compared to natural communities, under similar incubation conditions. Furthermore, these findings highlight the challenges that exist in using the synthetic community approach to modeling dynamics and species interactions in natural communities.

  7. 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…

  8. Physical activity in patients with stable coronary heart disease: an international perspective

    PubMed Central

    Stewart, Ralph; Held, Claes; Brown, Rebekkah; Vedin, Ola; Hagstrom, Emil; Lonn, Eva; Armstrong, Paul; Granger, Christopher B.; Hochman, Judith; Davies, Richard; Soffer, Joseph; Wallentin, Lars; White, Harvey

    2013-01-01

    Aims Despite the known benefits of regular exercise, the reasons why many coronary heart disease (CHD) patients engage in little physical activity are not well understood. This study identifies factors associated with low activity levels in individuals with chronic CHD participating in the STABILITY study, a global clinical outcomes trial evaluating the lipoprotein phospholipaseA2 inhibitor darapladib. Methods and results Prior to randomization, 15 486 (97.8%) participants from 39 countries completed a lifestyle questionnaire. Total physical activity was estimated from individual subject self-reports of hours spend each week on mild, moderate, and vigorous exercise, corresponding approximately to 2, 4, and 8 METS, respectively. Multivariate logistic regression evaluated clinical and demographic variables for the lowest compared with higher overall exercise levels, and for individuals who decreased rather than maintained or increased activity since diagnosis of CHD. The least active 5280 subjects (34%) reported exercise of ≤24MET.h/week. A total of 7191 subjects (46%) reported less exercise compared with before diagnosis of CHD. The majority of participants were either ‘not limited’ or ‘limited a little’ walking 100 m (84%), climbing one flight of stairs (82%), or walking 1 km/½ mile (68%), and <10% were limited ‘a lot’ by dyspnoea or angina. Variables independently associated with both low physical activity and decreasing exercise after diagnosis of CHD included more co-morbid conditions, poorer general health, fewer years of education, race, and country (P < 0.001 for all). Conclusion In this international study, low physical activity was only partly explained by cardiovascular symptoms. Potentially modifiable societal and health system factors are important determinants of physical inactivity in patients with chronic CHD. PMID:24014220

  9. Using self-determination theory to promote adolescent girls' physical activity: Exploring the theoretical fidelity of the Bristol Girls Dance Project

    PubMed Central

    Sebire, Simon J.; Kesten, Joanna M.; Edwards, Mark J.; May, Thomas; Banfield, Kathryn; Tomkinson, Keeley; Blair, Peter S.; Bird, Emma L.; Powell, Jane E.; Jago, Russell

    2016-01-01

    Objectives To report the theory-based process evaluation of the Bristol Girls' Dance Project, a cluster-randomised controlled trial to increase adolescent girls' physical activity. Design A mixed-method process evaluation of the intervention's self-determination theory components comprising lesson observations, post-intervention interviews and focus groups. Method Four intervention dance lessons per dance instructor were observed, audio recorded and rated to estimate the use of need-supportive teaching strategies. Intervention participants (n = 281) reported their dance instructors' provision of autonomy-support. Semi-structured interviews with the dance instructors (n = 10) explored fidelity to the theory and focus groups were conducted with participants (n = 59) in each school to explore their receipt of the intervention and views on the dance instructors' motivating style. Results Although instructors accepted the theory-based approach, intervention fidelity was variable. Relatedness support was the most commonly observed need-supportive teaching behaviour, provision of structure was moderate and autonomy-support was comparatively low. The qualitative findings identified how instructors supported competence and developed trusting relationships with participants. Fidelity was challenged where autonomy provision was limited to option choices rather than input into the pace or direction of lessons and where controlling teaching styles were adopted, often to manage disruptive behaviour. Conclusion The successes and challenges to achieving theoretical fidelity in the Bristol Girls' Dance Project may help explain the intervention effects and can more broadly inform the design of theory-based complex interventions aimed at increasing young people's physical activity in after-school settings. PMID:27175102

  10. Size counts: evolutionary perspectives on physical activity and body size from early hominids to modern humans.

    PubMed

    Leonard, William R

    2010-11-01

    This paper examines the evolutionary origins of human dietary and activity patterns, and their implications for understanding modern health problems. Humans have evolved distinctive nutritional characteristics associated the high metabolic costs of our large brains. The evolution of larger hominid brain size necessitated the adoption of foraging strategies that both provided high quality foods, and required larger ranges and activity budgets. Over time, human subsistence strategies have become ever more efficient in obtaining energy with minimal time and effort. Today, populations of the industrialized world live in environments characterized by low levels of energy expenditure and abundant food supplies contributing to growing rates of obesity. Analyses of trends in dietary intake and body weight in the US over the last 50 years indicate that the dramatic rise in obesity cannot be explained solely by increased energy consumption. Rather, declines in activity are also important. Further, we find that recent recommendations on physical activity have the potential to bring daily energy expenditure levels of industrialized societies surprisingly close to those observed among subsistence-level populations. These findings highlight the importance of physical activity in promoting nutritional health and show the utility of evolutionary approaches for developing public health recommendations.

  11. Perspectives of the AMP-activated kinase (AMPK) signalling pathway in thyroid cancer.

    PubMed

    Andrade, Bruno Moulin; de Carvalho, Denise Pires

    2014-04-01

    Approximately 90% of non-medullary thyroid malignancies originate from the follicular cell and are classified as papillary or follicular (well-differentiated) thyroid carcinomas, showing an overall favourable prognosis. However, recurrence or persistence of the disease occurs in some cases associated with the presence of loco-regional or distant metastatic lesions that generally become resistant to radioiodine therapy, while glucose uptake and metabolism are increased. Recent advances in the field of tumor progression have shown that CTC (circulating tumour cells) are metabolic and genetically heterogeneous. There is now special interest in unravelling the mechanisms that allow the reminiscence of dormant tumour lesions that might be related to late disease progression and increased risk of recurrence. AMPK (AMP-activated protein kinase) is activated by the depletion in cellular energy levels and allows adaptive changes in cell metabolism that are fundamental for cell survival in a stressful environment; nevertheless, the activation of this kinase also decreases cell proliferation rate and induces tumour cell apoptosis. In the thyroid field, AMPK emerged as a novel important intracellular pathway, since it regulates both iodide and glucose uptakes in normal thyroid cells. Furthermore, it has recently been demonstrated that the AMPK pathway is highly activated in papillary thyroid carcinomas, although the clinical significance of these findings remains elusive. Herein we review the current knowledge about the role of AMPK activation in thyroid physiology and pathophysiology, with special focus on thyroid cancer.

  12. Perspectives of the AMP-activated kinase (AMPK) signalling pathway in thyroid cancer

    PubMed Central

    Andrade, Bruno Moulin; de Carvalho, Denise Pires

    2014-01-01

    Approximately 90% of non-medullary thyroid malignancies originate from the follicular cell and are classified as papillary or follicular (well-differentiated) thyroid carcinomas, showing an overall favourable prognosis. However, recurrence or persistence of the disease occurs in some cases associated with the presence of loco-regional or distant metastatic lesions that generally become resistant to radioiodine therapy, while glucose uptake and metabolism are increased. Recent advances in the field of tumor progression have shown that CTC (circulating tumour cells) are metabolic and genetically heterogeneous. There is now special interest in unravelling the mechanisms that allow the reminiscence of dormant tumour lesions that might be related to late disease progression and increased risk of recurrence. AMPK (AMP-activated protein kinase) is activated by the depletion in cellular energy levels and allows adaptive changes in cell metabolism that are fundamental for cell survival in a stressful environment; nevertheless, the activation of this kinase also decreases cell proliferation rate and induces tumour cell apoptosis. In the thyroid field, AMPK emerged as a novel important intracellular pathway, since it regulates both iodide and glucose uptakes in normal thyroid cells. Furthermore, it has recently been demonstrated that the AMPK pathway is highly activated in papillary thyroid carcinomas, although the clinical significance of these findings remains elusive. Herein we review the current knowledge about the role of AMPK activation in thyroid physiology and pathophysiology, with special focus on thyroid cancer. PMID:27919039

  13. Chinese Children's Reading Acquisition: Theoretical and Pedagogical Issues.

    ERIC Educational Resources Information Center

    Li, Wenling, Ed.; Gaffney, Janet S., Ed.; Packard, Jerome L., Ed.

    This book provides comprehensive resources for the critical discussion of major issues in learning to read Chinese from a child acquisition perspective. It is divided into 4 parts and 11 chapters. Part 1, "Theoretical Perspectives on Learning to Read" includes "Current Issues in Learning To Read Chinese" (Ovid J.L. Tzeng),…

  14. Links between osteoarthritis and diabetes: implications for management from a physical activity perspective.

    PubMed

    Piva, Sara R; Susko, Allyn M; Khoja, Samannaaz S; Josbeno, Deborah A; Fitzgerald, G Kelley; Toledo, Frederico G S

    2015-02-01

    Osteoarthritis (OA) and type 2 diabetes mellitus (T2DM) often coexist in older adults. Those with T2DM are more susceptible to developing arthritis, which has been traditionally attributed to common risk factors, namely, age and obesity. Alterations in lipid metabolism and hyperglycemia might directly impact cartilage health and subchondral bone, contributing to the development/progression of OA. Adequate management of older persons with both conditions benefits from a comprehensive understanding of the associated risk factors. We discuss common risk factors and emerging links between OA and T2DM, emphasizing the importance of physical activity and the implications of safe and effective physical activity.

  15. Children's Perspectives on Their Economic Activity as a Pathway to Resilience

    ERIC Educational Resources Information Center

    Liborio, Renata Maria Coimbra; Ungar, Michael

    2010-01-01

    When viewed in the context of children's physical, social, and economic ecologies, children's work has both contextually specific benefits and consequences. This paper examines children's experiences of their economic activity using a theory of resilience as a contextually and culturally embedded phenomenon [British Journal of Social Work, 38…

  16. College Students' Physical Activity and Health-Related Quality of Life: An Achievement Goal Perspective

    ERIC Educational Resources Information Center

    Zhang, Tao; Xiang, Ping; Gu, Xiangli; Rose, Melanie

    2016-01-01

    Purpose: The 2 × 2 achievement goal model, including the mastery-approach, mastery-avoidance, performance-approach, and performance-avoidance goal orientations, has recently been used to explain motivational outcomes in physical activity. This study attempted to examine the relationships among 2 × 2 achievement goal orientations, physical…

  17. Metabolic, anabolic, and mitogenic insulin responses: A tissue-specific perspective for insulin receptor activators

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insulin acts as the major regulator of the fasting-to-fed metabolic transition by altering substrate metabolism, promoting energy storage, and helping activate protein synthesis. In addition to its glucoregulatory and other metabolic properties, insulin can also act as a growth factor. The metabolic...

  18. Relevance of Student Teaching Skills and Activities from the Perspective of the Student Teacher

    ERIC Educational Resources Information Center

    Smalley, Scott W.; Retallick, Michael S.; Paulsen, Thomas H.

    2015-01-01

    The purpose of this descriptive survey study was to determine the extent to which student teachers deem traditional student teaching skills and activities relevant as part of the capstone student teaching experience. The study population consisted of all (N = 140) fall 2012 and spring 2013 agricultural education student teachers in the North…

  19. Ninth Graders' Energy Balance Knowledge and Physical Activity Behavior: An Expectancy-Value Perspective

    ERIC Educational Resources Information Center

    Chen, Senlin; Chen, Ang

    2012-01-01

    Expectancy beliefs and task values are two essential motivators in physical education. This study was designed to identify the relation between the expectancy-value constructs (Eccles & Wigfield, 1995) and high school students' physical activity behavior as associated with their energy balance knowledge. High school students (N = 195) in two…

  20. Physical Activity--Academic Achievement: Student and Teacher Perspectives on the "New" Nexus

    ERIC Educational Resources Information Center

    Macdonald, Doune; Abbott, Rebecca; lisahunter; Hay, Peter; McCuaig, Louise

    2014-01-01

    Background: The association between physical activity/fitness with cognitive and academic functioning has become a topic of considerable research interest. Increasingly, schooling systems are being expected to respond to these relationships through curricular and extra-curricular interventions. Purpose: This paper reports on the qualitative…