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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.

    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

  4. 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.

  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. Tau decays: A theoretical perspective

    SciTech Connect

    Marciano, W.J.

    1992-11-01

    Theoretical predictions for various tau decay rates are reviewed. Effects of electroweak radiative corrections are described. Implications for precision tests of the standard model and ``new physics`` searches are discussed. A perspective on the tau decay puzzle and 1-prong problem is given.

  7. Tau decays: A theoretical perspective

    SciTech Connect

    Marciano, W.J.

    1992-11-01

    Theoretical predictions for various tau decay rates are reviewed. Effects of electroweak radiative corrections are described. Implications for precision tests of the standard model and new physics'' searches are discussed. A perspective on the tau decay puzzle and 1-prong problem is given.

  8. 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…

  9. Organized out-of-school activities and peer relationships: theoretical perspectives and previous research.

    PubMed

    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 activities, like sports, arts, and school clubs, are ideal settings to examine peer processes. Next, we describe the theoretical and empirical research related to two questions: (1) how do peers influence organized activity participation and (2) how does organized activity participation influence peer relations. We organize this review around three themes outlined in the broader peer relations literature: (1) peer groups, (2) peer relationships, and (3) peer interactions. PMID:23766093

  10. Theoretical Perspectives on Sibling Relationships

    PubMed Central

    Whiteman, Shawn D.; McHale, Susan M.; Soli, Anna

    2011-01-01

    Although siblings are a fixture of family life, research on sibling relationships lags behind that on other family relationships. To stimulate interest in sibling research and to serve as a guide for future investigations by family scholars, we review four theoretical psychologically oriented perspectives—(a) psychoanalytic-evolutionary, (b) social psychological, (c) social learning, and (d) family-ecological systems—that can inform research on sibling relationships, including perspectives on the nature and influences on developmental, individual, and group differences in sibling relationships. Given that most research on siblings has focused on childhood and adolescence, our review highlights these developmental periods, but we also incorporate the limited research on adult sibling relationships, including in formulating suggestions for future research on this fundamental family relationship. PMID:21731581

  11. 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…

  12. 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…

  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 of…

  14. 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…

  15. 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.

  16. 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

  17. 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.

  18. Theoretical perspectives on strange physics

    NASA Astrophysics Data System (ADS)

    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 rate modes with satisfying statistics. Kaons and their decays have provided at least two major breakthroughs in fundamental physics: CP violation, and their lack of flavor-changing neutral interactions warned us to expect charm. In addition, K0-anti K0 mixing has provided one of the 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 fundamental physics. This talk attempts to set future kaon experiments in a general theoretical context, and indicate how they 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, (SIGMA) decays, hyperon decays and neutrino physics is given.

  19. 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)

  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. 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…

  2. Autonomy: an information theoretic perspective.

    PubMed

    Bertschinger, Nils; Olbrich, Eckehard; Ay, Nihat; Jost, Jürgen

    2008-02-01

    We present a tentative proposal for a quantitative measure of autonomy. This is something that, surprisingly, is rarely found in the literature, even though autonomy is considered to be a basic concept in many disciplines, including artificial life. We work in an information theoretic setting for which the distinction between system and environment is the starting point. As a first measure for autonomy, we propose the conditional mutual information between consecutive states of the system conditioned on the history of the environment. This works well when the system cannot influence the environment at all and the environment does not interact synergetically with the system. When, in contrast, the system has full control over its environment, we should instead neglect the environment history and simply take the mutual information between consecutive system states as a measure of autonomy. In the case of mutual interaction between system and environment there remains an ambiguity regarding whether system or environment has caused observed correlations. If the interaction structure of the system is known, we define a "causal" autonomy measure which allows this ambiguity to be resolved. Synergetic interactions still pose a problem since in this case causation cannot be attributed to the system or the environment alone. Moreover, our analysis reveals some subtle facets of the concept of autonomy, in particular with respect to the seemingly innocent system-environment distinction we took for granted, and raises the issue of the attribution of control, i.e. the responsibility for observed effects. To further explore these issues, we evaluate our autonomy measure for simple automata, an agent moving in space, gliders in the game of life, and the tessellation automaton for autopoiesis of Varela et al. [Varela, F.J., Maturana, H.R., Uribe, R., 1974. Autopoiesis: the organization of living systems, its characterization and a model. BioSystems 5, 187-196]. PMID:17897774

  3. Tau physics 1994: A theoretical perspective

    SciTech Connect

    Marciano, W.J.

    1994-11-01

    In this paper I describe some recent advances in tau physics and discuss their implications from a theoretical perspective. The examples I have chosen include e-{mu}-{tau} universality, QCD studies, anomalous electroweak dipole moments, and forbidden decays. That list is by no means exhaustive. It should, however, demonstrate the breath of tau physics, describe some interesting new results, and point out the potential for future advances.

  4. 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.

  5. 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. PMID:26865262

  6. 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

  7. 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…

  8. Grief as a Social Emotion: Theoretical Perspectives

    ERIC Educational Resources Information Center

    Jakoby, Nina R.

    2012-01-01

    The article explores a sociological perspective on grief as a social emotion. Focusing on the social bond with the deceased, the self-concept of the survivor or the power of feeling rules, general sociological theories of emotions (symbolic interactionism, structural theory, behavioral theory) have the potential to deepen the understanding of…

  9. 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

  10. Theoretical and Philosophical Perspectives to Problem Solving.

    ERIC Educational Resources Information Center

    Sherman, Thomas M.; And Others

    1988-01-01

    Five articles explore various theoretical aspects of problems and problem solving skills. Highlights include strategies to learn problem solving skills; knowledge structures; metacognition; behavioral processes and cognitive psychology; erotetic logic; creativity as an aspect of computer problem solving; and programing as a problem-solving…

  11. 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…

  12. Information-Theoretic Perspectives on Geophysical Models

    NASA Astrophysics Data System (ADS)

    Nearing, Grey

    2016-04-01

    To test any hypothesis about any dynamic system, it is necessary to build a model that places that hypothesis into the context of everything else that we know about the system: initial and boundary conditions and interactions between various governing processes (Hempel and Oppenheim, 1948, Cartwright, 1983). No hypothesis can be tested in isolation, and no hypothesis can be tested without a model (for a geoscience-related discussion see Clark et al., 2011). Science is (currently) fundamentally reductionist in the sense that we seek some small set of governing principles that can explain all phenomena in the universe, and such laws are ontological in the sense that they describe the object under investigation (Davies, 1990 gives several competing perspectives on this claim). However, since we cannot build perfect models of complex systems, any model that does not also contain an epistemological component (i.e., a statement, like a probability distribution, that refers directly to the quality of of the information from the model) is falsified immediately (in the sense of Popper, 2002) given only a small number of observations. Models necessarily contain both ontological and epistemological components, and what this means is that the purpose of any robust scientific method is to measure the amount and quality of information provided by models. I believe that any viable philosophy of science must be reducible to this statement. The first step toward a unified theory of scientific models (and therefore a complete philosophy of science) is a quantitative language that applies to both ontological and epistemological questions. Information theory is one such language: Cox' (1946) theorem (see Van Horn, 2003) tells us that probability theory is the (only) calculus that is consistent with Classical Logic (Jaynes, 2003; chapter 1), and information theory is simply the integration of convex transforms of probability ratios (integration reduces density functions to scalar

  13. 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.

  14. Theoretical perspectives accounting for adolescent homosexuality.

    PubMed

    Savin-Williams, R C

    1988-03-01

    Few topics in sexology elicit such a diversity of opinions and emotions as the question of etiology of homosexuality. Views frequently carry with them implicit or explicit messages concerning the psychologic health of this sexual orientation. Theories of sexual development usually portray adolescence as a critical time in the life course because of changes in: 1) anatomy and physiology; 2) psychologic functioning: the reawakening, renewal, and reliving of previously established sexual relations and drives; and/or 3) social conditions: an increased exposure and adherence to societal messages concerning appropriate and inappropriate social and sexual behaviors and relationships. This paper provides a brief overview of several major theories--evolutionary biology, psychoanalysis, and social processes--as they relate to the development of sexual orientation. In addition, an ethologic perspective that synthesizes various etiologic theories, as they relate to homosexuality during adolescence, is briefly reviewed. In these discussions, the issue of whether homosexuality is a normal or abnormal developmental state during adolescence is also addressed. PMID:3283091

  15. 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

  16. American Library History Literature, 1947-1997: Theoretical Perspectives?

    ERIC Educational Resources Information Center

    Wiegand, Wayne A.

    2000-01-01

    Reviews 50 years of published research literature in American library history that shows a lack of theoretical perspective. Suggests that library historians should join with critical theorists and with social and cultural historians to help place the library in a larger context of social and cultural forces. (Contains 131 references.) (LRW)

  17. Philosophical Foundations and Current Theoretical Perspectives in Qualitative Research.

    ERIC Educational Resources Information Center

    Broido, Ellen M.; Manning, Kathleen

    2002-01-01

    The relationship between the philosophy, theory, and methods of different research paradigms is explored in this article. Specific theoretical perspectives, critical theory, postmodernism, critical race theory, queer theory, and feminist theory are explored in the context of their political values and implications for qualitative research.…

  18. Diffusion at the magnetopause: A theoretical perspective

    SciTech Connect

    Winske, D.; Thomas, V.A.; Omidi, N.

    1994-04-01

    This paper discusses theoretical aspects of cross-field wave-particle transport at the magnetopause. The basic framework for calculating the transport based on second order-theory is reviewed. Instabilities that give rise to the waves which then lead to particle scattering and diffusion are discussed, and in particular, the lower hybrid drift instability is emphasized. The linear and nonlinear properties of this instability are presented, along with results from revelant computer simulations. Other potential diffusion processes at the magnetopause are also described. The overall conclusion, supported by wave and particle observations, is that wave-particle diffusion is a relatively weak process at the magnetopause. Further, it is argued that this line of research, while illuminating potential new mechanisms, cannot address the more important question of diffusion and transport on a spatial scale of many ion gyroradii over a temporal scale of many ion gyroperiods. A new paradigm to examine the global aspects of magnetopause transport on ion scales using hybrid code methods is presented. Results of two-dimensional hybrid simulations show that the structure of the magnetopause for northward interplanetary magnetic field is reproduced, and the resulting transport in this case is due to waves below the ion gyrofrequency. Diffusion in the presence of viscous transport due to the kinetic Kelvin-Helmholtz instability is then discussed. The potential for the study of particle diffusion, viscous interactions and magnetic reconnection simultaneously through this paradigm is also addressed.

  19. Rapid evolution of quantitative traits: theoretical perspectives

    PubMed Central

    Kopp, Michael; Matuszewski, Sebastian

    2014-01-01

    An increasing number of studies demonstrate phenotypic and genetic changes in natural populations that are subject to climate change, and there is hope that some of these changes will contribute to avoiding species extinctions (‘evolutionary rescue’). Here, we review theoretical models of rapid evolution in quantitative traits that can shed light on the potential for adaptation to a changing climate. Our focus is on quantitative-genetic models with selection for a moving phenotypic optimum. We point out that there is no one-to-one relationship between the rate of adaptation and population survival, because the former depends on relative fitness and the latter on absolute fitness. Nevertheless, previous estimates that sustainable rates of genetically based change usually do not exceed 0.1 haldanes (i.e., phenotypic standard deviations per generation) are probably correct. Survival can be greatly facilitated by phenotypic plasticity, and heritable variation in plasticity can further speed up genetic evolution. Multivariate selection and genetic correlations are frequently assumed to constrain adaptation, but this is not necessarily the case and depends on the geometric relationship between the fitness landscape and the structure of genetic variation. Similar conclusions hold for adaptation to shifting spatial gradients. Recent models of adaptation in multispecies communities indicate that the potential for rapid evolution is strongly influenced by interspecific competition. PMID:24454555

  20. Phytoestrogens in postmenopausal indications: A theoretical perspective

    PubMed Central

    Sunita, P.; Pattanayak, S. P.

    2011-01-01

    This review discusses plant-derived compounds with estrogenic activity. The authors rightly emphasize the need for the intake of foods containing phytoestrogens in view of their positive effects on postmenopausal indications. This is particularly significant in the light of the current wave of enthusiasm for vegetarian food, in general, and phytoestrogens, in particular. Phytoestrogens are plant-derived hormone-like diphenolic compounds of dietary origin. These compounds are weakly estrogenic and could play a role in the prevention of other estrogen-related conditions, namely, cardiovascular diseases, menopausal symptoms, postmenopausal osteoporosis, neuroprotective effects, and hormone-dependent cancers (breast and endometrium cancer). PMID:22096317

  1. 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…

  2. On the Worthwhileness of Theoretical Activities

    ERIC Educational Resources Information Center

    Hand, Michael

    2009-01-01

    R.S. Peters' arguments for the worthwhileness of theoretical activities are intended to justify education per se, on the assumption that education is necessarily a matter of initiating people into theoretical activities. If we give up this assumption, we can ask whether Peters' arguments might serve instead to justify the academic curriculum over…

  3. 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.

  4. Racial/Ethnic disparities in depression and its theoretical perspectives.

    PubMed

    Kim, Minjeong

    2014-03-01

    The purpose of this review is to look at racial/ethnic disparities in the diagnosis of depression and its treatment and to explain the dynamics and causes of these racial/ethnic disparities in depression by looking at several theories, such as perceived racism, cultural competency, and other theories. Perceived racism is that the perceptions of an environmental stimulus as being racist affects the coping responses of ethnic/racial minorities, which alters psychological and physiological stress responses, and finally affects health outcomes negatively. A lower level of cultural competence can lead to health disparities. In addition, lower socioeconomic status and health care providers' beliefs and behaviors about patients' race/ethnicity and class can affect depressive symptoms as well as diagnosis and treatment. In order to reduce these racial/ethnic disparities in depression, diverse interventions should be developed to improve depression outcomes for ethnic minority populations based on these theoretical perspectives. PMID:23801269

  5. Theoretical perspectives and applications of group learning in PBL.

    PubMed

    Torre, Dario M; van der Vleuten, Cees; Dolmans, Diana

    2016-01-01

    An essential part of problem-based learning (PBL) is group learning. Thus, an in depth understanding of the theoretical underpinnings of group learning in PBL allows educators to bridge theory and practice more effectively thus providing ideas and tools to enhance PBL practices and research. The theory-driven applications examined in this article establish grounds for future research in PBL. The purpose of this article is to describe and examine two theoretical perspectives of group learning in PBL and their potential applications to improve educational practice. They include: (1) social interdependence theory and the meaning of positive interdependence, (2) socio cognitive theory of networked expertise and the concept of knowledge creation in innovative knowledge communities (IKC). Potential applications include the following: development of instructional material to foster positive interdependency using concept maps; formal and structured use of peer feedback throughout PBL courses to promote individual and group accountability; creation and sharing of new knowledge about different topics within and across IKC; and use of rotating students with hybrid abilities across PBL groups to foster distributed cognition. PMID:26075957

  6. 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. PMID:16489736

  7. 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

  8. Theoretical and Pedagogical Perspectives on Orchestrating Creativity and Collaborative Learning

    ERIC Educational Resources Information Center

    Hamalainen, Raija; Vahasantanen, Katja

    2011-01-01

    The role of teacher is increasingly related to designing and arranging collaborative learning situations in which fruitful and creative group work may occur. This thematic review presents recent studies on creativity and collaborative learning from the perspective of the teacher as conductor of learning processes. The precondition for the design…

  9. 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. PMID:25125368

  10. Optical activity in planar chiral metamaterials: Theoretical study

    SciTech Connect

    Bai, Benfeng; Svirko, Yuri; Turunen, Jari; Vallius, Tuomas

    2007-08-15

    A thorough theoretical study of the optical activity in planar chiral metamaterial (PCM) structures, made of both dielectric and metallic media, is conducted by the analysis of gammadion-shaped nanoparticle arrays. The general polarization properties are first analyzed from an effective-medium perspective, by analogy with natural optical activity, and then verified by rigorous numerical simulation, some of which are corroborated by previous experimental results. The numerical analysis suggests that giant polarization rotation (tens of degrees) may be achieved in the PCM structures with a thickness of only hundreds of nanometers. The artificial optical activity arises from circular birefringence induced by the structural chirality and is enhanced by the guided-mode or surface-plasmon resonances taking place in the structures. There are two polarization conversion types in the dielectric PCMs, whereas only one type in the metallic ones. Many intriguing features of the polarization property of PCMs are also revealed and explained: the polarization effect is reciprocal and vanishes in the symmetrically layered structures; the effect occurs only in the transmitted field, but not in the reflected field; and the polarization spectra of two enantiomeric PCM structures are mirror symmetric to each other. These remarkable properties pave the way for the PCMs to be used as polarization elements in new-generation integrated optical systems.

  11. Historical and Theoretical Perspectives on Appalachia's Economic Dependency.

    ERIC Educational Resources Information Center

    Salstrom, Paul

    The roots of Appalachia's economic dependency go back to the region's first settlers in the 1730s. Historical and theoretical analysis of this phenomenon is useful in understanding the current status of the area, including, the status of education. The early settler sought a "competency"--enough productive property to support a family. Under…

  12. 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…

  13. 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…

  14. 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)

  15. An Information-Theoretic Perspective of Tf-idf Measures.

    ERIC Educational Resources Information Center

    Aizawa, Akiko

    2003-01-01

    Presents a mathematical definition of the probability-weighted amount of information (PWI), a measure of term specificity in documents that is based on an information-theoretic view of retrieval events. Corresponds with the term frequency-inverse document frequency (tf-idf) measures that are used in information retrieval systems. (Author/LRW)

  16. Intelligent systems: A semiotic perspective. Volume I: Theoretical semiotics

    SciTech Connect

    Albus, J.; Meystel, A.; Quintero, R.

    1996-12-31

    This report contains the papers from the Proceedings of the 1996 International Multidisciplinary Conference - Theoretical Semiotics. General topics covered are: semiotic in biology: biologically inspired complex systems; intelligence in constructed complex systems; intelligence of learning and evolution; fuzzy logic and the mechanisms of generalization; information representation for decision making; sematic foundations; syntactics of intelligent systems: the kind of logic available; intelligence of recognition: the semiotic tools; and multiresolutional methods.

  17. Cognitive training and plasticity: Theoretical perspective and methodological consequences

    PubMed Central

    Willis, Sherry L.; Schaie, K. Warner

    2013-01-01

    Purpose To provide an overview of cognitive plasticity concepts and findings from a lifespan developmental perspective. Methods After an evaluation of the general concept of cognitive plasticity, the most important approaches to study behavioral and brain plasticity are reviewed. This includes intervention studies, experimental approaches, cognitive trainings, the study of facilitating factors for strategy learning and strategy use, practice, and person-environment interactions. Transfer and durability of training-induced plasticity is discussed. Results The review indicates that methodological and conceptual advances are needed to improve the match between levels of behavioral and brain plasticity targeted in current developmental research and study designs. Conclusions The results suggest that the emphasis of plasticity studies on treatment effectiveness needs to be complemented by a strong commitment to the grounding of the intervention in a conceptual framework. PMID:19847065

  18. 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. PMID:15596970

  19. 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.

  20. 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.

  1. Toward a Theoretical Model of Employee Turnover: A Human Resource Development Perspective

    ERIC Educational Resources Information Center

    Peterson, Shari L.

    2004-01-01

    This article sets forth the Organizational Model of Employee Persistence, influenced by traditional turnover models and a student attrition model. The model was developed to clarify the impact of organizational practices on employee turnover from a human resource development (HRD) perspective and provide a theoretical foundation for research on…

  2. 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…

  3. Theoretical Perspectives on the Education of Choral Conductors: A Suggested Framework

    ERIC Educational Resources Information Center

    Varvarigou, Maria; Durrant, Colin

    2011-01-01

    This paper presents theoretical perspectives for choral conducting education. A wide range of related literature on choral practice and education in higher education contexts, as well as training in the workplace is reviewed. Whilst various attributes for effective choral conducting practice have been identified by research studies, there has been…

  4. 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…

  5. 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…

  6. 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)

  7. "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…

  8. Gender and Autonomy-Supportive Contexts: Theoretical Perspectives of Self-Determination and Goal Setting

    ERIC Educational Resources Information Center

    Lin, Shinyi; Chen, Yu-Chuan

    2013-01-01

    In integrating theoretical perspectives of self-determination and goal-setting, this study proposes a conceptual model with moderating and mediating effects exploring gender issue in autonomy-supportive learning in higher education as research context. In the proposed model, goal-setting attributes, i.e., individual determinants, social…

  9. 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…

  10. 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.

  11. The neural representation of time: an information-theoretic perspective.

    PubMed

    Hass, Joachim; Herrmann, J Michael

    2012-06-01

    A prominent finding in psychophysical experiments on time perception is Weber's law, the linear scaling of timing errors with duration. The ability to reproduce this scaling has been taken as a criterion for the validity of neurocomputational models of time perception. However, the origin of Weber's law remains unknown, and currently only a few models generically reproduce it. Here, we use an information-theoretical framework that considers the neuronal mechanisms of time perception as stochastic processes to investigate the statistical origin of Weber's law in time perception and also its frequently observed deviations. Under the assumption that the brain is able to compute optimal estimates of time, we find that Weber's law only holds exactly if the estimate is based on temporal changes in the variance of the process. In contrast, the timing errors scale sublinearly with time if the systematic changes in the mean of a process are used for estimation, as is the case in the majority of time perception models, while estimates based on temporal correlations result in a superlinear scaling. This hierarchy of temporal information is preserved if several sources of temporal information are available. Furthermore, we consider the case of multiple stochastic processes and study the examples of a covariance-based model and a model based on synfire chains. This approach reveals that existing neurocomputational models of time perception can be classified as mean-, variance- and correlation-based processes and allows predictions about the scaling of the resulting timing errors. PMID:22364498

  12. 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…

  13. 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

  14. 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.

  15. 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. PMID:22452298

  16. 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.

  17. 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

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

    PubMed

    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

  19. 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…

  20. Theoretical basis for the activity of thalidomide.

    PubMed

    Meierhofer, C; Dunzendorfer, S; Wiedermann, C J

    2001-01-01

    The revival of thalidomide began shortly after the drug was withdrawn from the market because of its teratogenic properties. Therapeutic effects of thalidomide were found accidentally in leprosy patients with erythema nodosum leprosum (ENL). Subsequent research widened the understanding of the activity of thalidomide, and with improved methodology and the augmented background knowledge of immunology it was possible to interpret the properties of thalidomide more coherently. Effects on tumour necrosis factor-alpha (TNFalpha) release play an important role in the ability of thalidomide to affect the immune system. Alteration of synthesis and release of cytokines such as interleukin (IL)-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12 and interferon-gamma is involved in the complex mechanisms of thalidomide. Thalidomide targets leucocytes, endothelial cells and keratinocytes, affecting them in a different manner and at different cellular levels. Changes in the density of adhesion molecules alter leucocyte extravasation and the inflammatory response in the tissue involved. Several mechanisms for the teratogenic action of thalidomide are currently under review, but this mode of action of the drug still remains unclear and we review evidence-based hypotheses for the teratogenicity of thalidomide. Thalidomide shows significant clinical impact in several diseases such as ENL in lepromatous leprosy, chronic graft-versus-host disease, systemic lupus erythematosus, sarcoidosis, aphthous lesions in HIV infection, wasting syndrome in chronic illness, inflammatory bowel disease, multiple myeloma and some solid tumours. In 1998 the US Food and Drug Administration approved thalidomide exclusively for the treatment of ENL, and strict conditions were stipulated for its use in order to prevent teratogenic adverse effects. However, despite the promising findings of thalidomide at the molecular level, namely its anti-TNFalpha properties and its intercalation with DNA, and activity in clinical

  1. 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

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

    PubMed

    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

  3. 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. PMID:16541817

  4. 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. PMID:26502554

  5. Perspectives on Learning, Thinking, and Activity.

    ERIC Educational Resources Information Center

    Anderson, John R.; Greeno, James G.; Reder, Lynne M.; Simon, Herbert A.

    2000-01-01

    Discusses the cognitive and situative research approaches, identifying several points on which they agree (e.g., individual and social perspectives on activity are fundamental in education; learning can be general, and abstractions can be efficacious, but sometimes they are not; and situative and cognitive approaches can cast light on different…

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

    PubMed

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

    2016-02-01

    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 a theoretical literature, were view 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

  7. Perspectives on Student Political Activism.

    ERIC Educational Resources Information Center

    Altbach, Philip G.

    1989-01-01

    Presents a historical and international overview of student political movements. Discusses the sporadic nature of student activism, effects of mass media attention and government response, characteristics of activist leaders and participants, and the cultural and educational impact of student protest in Third World and industrialized countries.…

  8. 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…

  9. Incorporating a multilevel perspective into occupational stress research: theoretical, methodological, and practical implications.

    PubMed

    Bliese, Paul D; Jex, Steve M

    2002-07-01

    In recent years, scholars in organizational behavior and public health have recognized the value of multilevel modeling. This article draws from both of these fields to illustrate the benefits of incorporating a multilevel perspective into the study of occupational stress. The authors identify key multilevel issues in occupational stress in terms of (a) individual-level analyses, (b) group-level analyses, and (c) cross-level analyses. They integrate the theoretical points with statistical models to help illustrate how one can test multilevel occupational stress propositions. PMID:12148957

  10. 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.…

  11. Mono- and binuclear non-heme iron chemistry from a theoretical perspective.

    PubMed

    Rokob, Tibor András; Chalupský, Jakub; Bím, Daniel; Andrikopoulos, Prokopis C; Srnec, Martin; Rulíšek, Lubomír

    2016-09-01

    In this minireview, we provide an account of the current state-of-the-art developments in the area of mono- and binuclear non-heme enzymes (NHFe and NHFe2) and the smaller NHFe(2) synthetic models, mostly from a theoretical and computational perspective. The sheer complexity, and at the same time the beauty, of the NHFe(2) world represents a challenge for experimental as well as theoretical methods. We emphasize that the concerted progress on both theoretical and experimental side is a conditio sine qua non for future understanding, exploration and utilization of the NHFe(2) systems. After briefly discussing the current challenges and advances in the computational methodology, we review the recent spectroscopic and computational studies of NHFe(2) enzymatic and inorganic systems and highlight the correlations between various experimental data (spectroscopic, kinetic, thermodynamic, electrochemical) and computations. Throughout, we attempt to keep in mind the most fascinating and attractive phenomenon in the NHFe(2) chemistry, which is the fact that despite the strong oxidative power of many reactive intermediates, the NHFe(2) enzymes perform catalysis with high selectivity. We conclude with our personal viewpoint and hope that further developments in quantum chemistry and especially in the field of multireference wave function methods are needed to have a solid theoretical basis for the NHFe(2) studies, mostly by providing benchmarking and calibration of the computationally efficient and easy-to-use DFT methods. PMID:27229513

  12. Theoretical perspective of alcohol decomposition and synthesis from CO2 hydrogenation

    NASA Astrophysics Data System (ADS)

    Liu, Ping; Yang, Yixiong; White, Michael G.

    2013-06-01

    Advances in theoretical methods, in particular density functional theory (DFT), make it possible to describe catalytic reactions at surfaces with the detail and accuracy required for computational results to compare with experiment in a meaningful way. The theoretical studies also describe chemical reaction networks and understand variations in catalytic activity from one catalyst to another. Such understanding allows the theoretical optimization for better catalysts. In the current report we discussed the theoretical studies in the past few years on decomposition and synthesis of methanol and ethanol on various catalyst surfaces. The knowledge of reactions including the intermediates and transition states along different reaction pathways together with kinetic modeling was demonstrated. The theoretical studies on alcohol synthesis help gain better understanding of the complex kinetics and the roles that each component of a catalyst plays. In general, moving from mono-functional catalysts to multi-functional catalysts by increasing the complexity offers new opportunities to tune the behavior of a catalyst. A good multi-functional catalyst is not necessary to compromise the binding strong enough to adsorb and dissociate reactants and weak enough to allow the formation of intermediates and removal of products; instead, it may take advantage of each component, which catalyzes different elementary steps depending on its unique activity. The synergy between the different components can enable the multi-functional catalyst a novel activity in catalysis. This is of great importance for rational design of better catalysts for alcohol renewal synthesis and efficient use.

  13. Theoretical perspective of alcohol decomposition and synthesis from CO2 hydrogenation

    NASA Astrophysics Data System (ADS)

    Liu, Ping; Yang, Yixiong; White, Michael G.

    2013-06-01

    Advances in theoretical methods, in particular density functional theory (DFT), make it possible to describe catalytic reactions at surfaces with the detail and accuracy required for computational results to compare with experiment in a meaningful way. The theoretical studies also describe chemical reaction networks and understand variations in catalytic activity from one catalyst to another. Such understanding allows the theoretical optimization for better catalysts.In the current report we discussed the theoretical studies in the past few years on decomposition and synthesis of methanol and ethanol on various catalyst surfaces. The knowledge of reactions including the intermediates and transition states along different reaction pathways together with kinetic modeling was demonstrated. The theoretical studies on alcohol synthesis help gain better understanding of the complex kinetics and the roles that each component of a catalyst plays. In general, moving from mono-functional catalysts to multi-functional catalysts by increasing the complexity offers new opportunities to tune the behavior of a catalyst. A good multi-functional catalyst is not necessary to compromise the binding strong enough to adsorb and dissociate reactants and weak enough to allow the formation of intermediates and removal of products; instead, it may take advantage of each component, which catalyzes different elementary steps depending on its unique activity. The synergy between the different components can enable the multi-functional catalyst a novel activity in catalysis. This is of great importance for rational design of better catalysts for alcohol renewal synthesis and efficient use.

  14. 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…

  15. 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

  16. [Between idealization and devaluation--problems and perspectives of theoretical analyses of female homo- and heterosexuality].

    PubMed

    Flaake, K

    1995-01-01

    Female homosexuality remains a controversial topic. Comparing psychoanalytic and sociological-feminist approaches to the phenomenon, the author points up clear theoretical distinctions between the two perspectives. Feminist authors tend towards an idealization of female homosexuality, while psychoanalysts display an inclination to devalue it as something pathological. However, the latent messages in both discourses have a number of points in common, traceable to a key problem they both have to come to grips with, the "lesbian complex". In lesbian relationships Flaake discerns a "third chance", an area not sanctioned by society, in which it is possible to re-attempt something left unattained in the early mother-daughter relationship: the appropriation of the female body. PMID:7480810

  17. 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. PMID:18641386

  18. The transmission of attachment across generations: The state of art and new theoretical perspectives.

    PubMed

    Sette, Giovanna; Coppola, Gabrielle; Cassibba, Rosalinda

    2015-06-01

    The paper reviews the body of research testing the intergenerational transmission of attachment and the theoretical shift from the linear or mediation model (van IJzendoorn, 1995), according to which parental sensitivity is the main factor responsible for the correspondence between maternal and infant's attachment, to the ecological model of the transmission of attachment (van IJzendoorn & Bakermans-Kranenburg, 1997). This latter model has prompted researchers, over time, to identify potential mediators, other than caregiver's sensitivity, of the established association between parental representations regarding attachment and infant's attachment, as well as the potential moderators of the transmission process. Each of these two research domains will be carefully explored; lastly new perspectives on the intergenerational transmission of attachment and relevant areas of research needing more investigation are highlighted. PMID:25810347

  19. Advances on BYY harmony learning: information theoretic perspective, generalized projection geometry, and independent factor autodetermination.

    PubMed

    Xu, Lei

    2004-07-01

    The nature of Bayesian Ying-Yang harmony learning is reexamined from an information theoretic perspective. Not only its ability for model selection and regularization is explained with new insights, but also discussions are made on its relations and differences from the studies of minimum description length (MDL), Bayesian approach, the bit-back based MDL, Akaike information criterion (AIC), maximum likelihood, information geometry, Helmholtz machines, and variational approximation. Moreover, a generalized projection geometry is introduced for further understanding such a new mechanism. Furthermore, new algorithms are also developed for implementing Gaussian factor analysis (FA) and non-Gaussian factor analysis (NFA) such that selecting appropriate factors is automatically made during parameter learning. PMID:15461081

  20. Is technology the best medicine? Three practice theoretical perspectives on medication administration technologies in nursing.

    PubMed

    Boonen, Marcel Jmh; Vosman, Frans Jh; Niemeijer, Alistair R

    2016-06-01

    Even though it is often presumed that the use of technology like medication administration technology is both safer and more effective, the importance of nurses' know-how is not to be underestimated. In this article, we accordingly try to argue that nurses' labor, including their different forms of knowledge, must play a crucial role in the development, implementation and use of medication administration technology. Using three different theoretical perspectives ('heuristic lenses') and integrating this with our own ethnographic research, we will explore how nursing practices change through the use of medication technology. Ultimately, we will argue that ignoring (institutional) complexity and the various types of important knowledge that nurses have, will seriously complicate the implementation of medication administration technology. PMID:26491844

  1. 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…

  2. 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…

  3. 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

  4. Utility and limitations of measures of health inequities: a theoretical perspective

    PubMed Central

    Alonge, Olakunle; Peters, David H.

    2015-01-01

    Summary box What is already known on this subject? Various measures have been used in quantifying health inequities among populations in recent times; most of these measures were derived to capture the socioeconomic inequalities in health. These different measures do not always lend themselves to common interpretation by policy makers and health managers because they each reflect limited aspects of the concept of health inequities. What does this study add? To inform a more appropriate application of the different measures currently used in quantifying health inequities, this article explicates common theories underlying the definition of health inequities and uses this understanding to show the utility and limitations of these different measures. It also suggests some key features of an ideal indicator based on the conceptual understanding, with the hope of influencing future efforts in developing more robust measures of health inequities. The article also provides a conceptual ‘product label’ for the common measures of health inequities to guide users and ‘consumers’ in making more robust inferences and conclusions. This paper examines common approaches for quantifying health inequities and assesses the extent to which they incorporate key theories necessary for explicating the definition of health inequity. The first theoretical analysis examined the distinction between inter-individual and inter-group health inequalities as measures of health inequities. The second analysis considered the notion of fairness in health inequalities from different philosophical perspectives. To understand the extent to which different measures of health inequities incorporate these theoretical explanations, four criteria were used to assess each measure: 1) Does the indicator demonstrate inter-group or inter-individual health inequalities or both; 2) Does it reflect health inequalities in relation to socioeconomic position; 3) Is it sensitive to the absolute transfer of

  5. 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.

  6. Synthesis, characterization, theoretical prediction of activities and evaluation of biological activities of some sulfacetamide based hydroxytriazenes.

    PubMed

    Agarwal, Shilpa; Baroliya, Prabhat K; Bhargava, Amit; Tripathi, I P; Goswami, A K

    2016-06-15

    Six new N [(4-aminophenyl)sulfonyl]acetamide based hydroxytriazenes have been synthesized and characterized using elemental analysis, IR, 1H NMR, 13C NMR and MASS spectral analysis. Further, their theoretical predictions for probable activities have been taken using PASS (Prediction of Activity Spectra for Substance). Although a number of activities have been predicted but specifically anti-inflammatory, antiradical, anti-diabetic activities have been experimentally validated which proves that theoretical predictions agree with the experimental results. The object of the Letter is to establish Computer Aided Drug Design (CADD) using our compounds. PMID:27136718

  7. 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…

  8. 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.

  9. On Algebraic Singularities, Finite Graphs and D-Brane Gauge Theories: A String Theoretic Perspective

    NASA Astrophysics Data System (ADS)

    He, Yang-Hui

    2002-09-01

    In this writing we shall address certain beautiful inter-relations between the construction of 4-dimensional supersymmetric gauge theories and resolution of algebraic singularities, from the perspective of String Theory. We review in some detail the requisite background in both the mathematics, such as orbifolds, symplectic quotients and quiver representations, as well as the physics, such as gauged linear sigma models, geometrical engineering, Hanany-Witten setups and D-brane probes. We investigate aspects of world-volume gauge dynamics using D-brane resolutions of various Calabi-Yau singularities, notably Gorenstein quotients and toric singularities. Attention will be paid to the general methodology of constructing gauge theories for these singular backgrounds, with and without the presence of the NS-NS B-field, as well as the T-duals to brane setups and branes wrapping cycles in the mirror geometry. Applications of such diverse and elegant mathematics as crepant resolution of algebraic singularities, representation of finite groups and finite graphs, modular invariants of affine Lie algebras, etc. will naturally arise. Various viewpoints and generalisations of McKay's Correspondence will also be considered. The present work is a transcription of excerpts from the first three volumes of the author's PhD thesis which was written under the direction of Prof. A. Hanany - to whom he is much indebted - at the Centre for Theoretical Physics of MIT, and which, at the suggestion of friends, he posts to the ArXiv pro hac vice; it is his sincerest wish that the ensuing pages might be of some small use to the beginning student.

  10. Theoretical model for calculation of helicity in solar active regions

    NASA Astrophysics Data System (ADS)

    Chatterjee, P.

    We (Choudhuri, Chatterjee and Nandy, 2005) calculate helicities of solar active regions based on the idea of Choudhuri (2003) that poloidal flux lines get wrapped around a toroidal flux tube rising through the convection zone, thereby giving rise to the helicity. Rough estimates based on this idea compare favourably with the observed magnitude of helicity. We use our solar dynamo model based on the Babcock--Leighton α-effect to study how helicity varies with latitude and time. At the time of solar maximum, our theoretical model gives negative helicity in the northern hemisphere and positive helicity in the south, in accordance with observed hemispheric trends. However, we find that, during a short interval at the beginning of a cycle, helicities tend to be opposite of the preferred hemispheric trends. Next we (Chatterjee, Choudhuri and Petrovay 2006) use the above idea along with the sunspot decay model of Petrovay and Moreno-Insertis, (1997) to estimate the distribution of helicity inside a flux tube as it keeps collecting more azimuthal flux during its rise through the convection zone and as turbulent diffusion keeps acting on it. By varying parameters over reasonable ranges in our simple 1-d model, we find that the azimuthal flux penetrates the flux tube to some extent instead of being confined to a narrow sheath outside.

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

    PubMed Central

    Fisher, Carla L.; Nussbaum, Jon F.

    2015-01-01

    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. PMID:26997920

  12. 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…

  13. 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. PMID:25589328

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

    PubMed

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

    2008-01-01

    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

  15. 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

  16. 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

  17. Synchronous brain activity across individuals underlies shared psychological perspectives.

    PubMed

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

    2014-10-15

    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

  18. Analytical perspectives on performance-based management: an outline of theoretical assumptions in the existing literature.

    PubMed

    Wadmann, Sarah; Johansen, Sarah; Lind, Ane; Okkels Birk, Hans; Hoeyer, Klaus

    2013-10-01

    Performance-based management (PBM) has become a dominant form of governance in health care and there is a need for careful assessment of its function and effects. This article contains a cross-disciplinary literature synthesis of current studies of PBM. Literature was retrieved by database searches and categorized according to analytical differences and similarities concerning (1) purpose and (2) governance mechanism of PBM. The literature could be grouped into three approaches to the study of PBM, which we termed: the ‘functionalist’, the ‘interpretive’ and the ‘post-modern’ perspective. In the functionalist perspective, PBM is perceived as a management tool aimed at improving health care services by means of market-based mechanisms. In the interpretive perspective, the adoption of PBM is understood as consequence of institutional and individual agents striving for public legitimacy. In the post-modern perspective, PBM is analysed as a form of governance, which has become so ingrained in Western culture that health care professionals internalize and understand their own behaviour and goals according to the values expressed in these governance systems. The recognition of differences in analytical perspectives allows appreciation of otherwise implicit assumptions and potential implications of PBM. Reflections on such differences are important to ensure vigilant appropriation of shifting management tools in health quality governance. PMID:23506797

  19. Chapter 4. A self-theoretical perspective on the use-misuse of alcohol and drugs based on qualitative and narrative data.

    PubMed

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

    2013-11-01

    This article discusses different self-theoretical perspectives of the self that are of importance in the analysis of the use and misuse of alcohol and psychoactive drugs. The self-theories considered here include cognitive, psychodynamic, transpersonal, and social constructivist perspectives. A multidimensional perspective focusing on the connection between identity structures and analyzing the use/misuse of alcohol and psychoactive drugs is presented. The article argues for a self-theoretical analysis based on narrative data in order to reach an in-depth understanding of the use and misuse of alcohol and psychoactive drugs. PMID:24087866

  20. 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…

  1. 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…

  2. 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…

  3. Alternative Theoretical Bases for the Study of Human Communication: The Systems Perspective.

    ERIC Educational Resources Information Center

    Monge, Peter R.

    Three potentially useful perspectives for the scientific development of human communication theory are the law model, the systems approach, and the rules paradigm. It is the purpose of this paper to indicate the utility of the systems approach. The first section of this paper provides a brief account of the systems view of the world. Outlined in…

  4. 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…

  5. 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)

  6. A microscopic field theoretical approach for active systems

    NASA Astrophysics Data System (ADS)

    Alaimo, F.; Praetorius, S.; Voigt, A.

    2016-08-01

    We consider a microscopic modeling approach for active systems. The approach extends the phase field crystal (PFC) model and allows us to describe generic properties of active systems within a continuum model. The approach is validated by reproducing results obtained with corresponding agent-based and microscopic phase field models. We consider binary collisions, collective motion and vortex formation. For larger numbers of particles we analyze the coarsening process in active crystals and identify giant number fluctuation in a cluster formation process.

  7. 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…

  8. 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…

  9. 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…

  10. Ecological risk and resilience perspective: a theoretical framework supporting evidence-based practice in schools.

    PubMed

    Powers, Joelle D

    2010-10-01

    Multidisciplinary school practitioners are clearly being called to use evidence-based practices from reputable sources such as their own professional organizations and federal agencies. In spite of this encouragement, most schools are not regularly employing empirically supported interventions. This paper further promotes the use of this approach by describing the theoretical support for evidence-based practice in schools. The ecological risk and resilience theoretical framework presented fills a gap in the literature and advocates for evidence-based practice in schools by illustrating how it can assist practitioners such as school social workers to better address problems associated with school failure. PMID:21082473

  11. International Centre for Theoretical Physics: Scientific activities in 1987

    NASA Astrophysics Data System (ADS)

    1988-12-01

    A review of the scientific activities of the ICTP Trieste in 1987, including workshops, research and training for research is presented. The scientific program consists of eight main fields: fundamental physics, condensed matter, atomic and molecular physics, mathematics, physics and energy, physics and environment, applied physics and high technology, physics and development. In addition to a brief description of each workshop, symposium, college, meeting and activity or project sponsored by ICTP, a list of preprints and internal reports issued in 1987 is included.

  12. Theoretical study of carbon dioxide activation by metals (Co, Cu, Ni) supported on activated carbon.

    PubMed

    Ha, Nguyen Ngoc; Ha, Nguyen Thi Thu; Van Khu, Le; Cam, Le Minh

    2015-12-01

    The activation of carbon dioxide (CO2) by catalytic systems comprising a transition metal (Co, Cu,Ni) on an activated carbon (AC) support was investigated using a combination of different theoretical calculation methods: Monte Carlo simulation, DFT and DFT-D, molecular dynamics (MD), and a climbing image nudged elastic band (CI-NEB) method. The results obtained indicate that CO2 is easily adsorbed by AC or MAC (M: Cu, Co, Ni). The results also showed that the process of adsorbing CO2 does not involve a transition state, and that NiAC and CoAC are the most effective of the MAC catalysts at adsorbing CO2. Adsorption on NiAC led to the strongest activation of the C-O bond, while adsorption on CuAC led to the weakest activation. Graphical Abstract Models of CO2 activation on: a)- activated carbon; b)- metal supported activated carbon (M-AC), where M: Co, Cu, Ni. PMID:26637187

  13. 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…

  14. 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…

  15. 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…

  16. Factors that Contribute to Talented Performance: A Theoretical Model from a Chinese Perspective

    ERIC Educational Resources Information Center

    Wu, Echo H.

    2005-01-01

    This paper examines the Chinese literature on giftedness and talented performance (TP) and compares its dominant theoretical features with some influential models to be found in the North American literature. One significant feature to emerge from the Chinese literature is a deemphasis on giftedness as an innate ability and an emphasis on the…

  17. Theoretical Perspectives on School Crime. Volume I, Chapter I: An Aesthetic Theory of School Vandalism.

    ERIC Educational Resources Information Center

    Allen, Vernon L.; Greenberger, David B.

    One of 52 theoretical papers on school crime and its relation to poverty, this chapter presents an aesthetic theory of vandalism and reports nine original empirical studies that are relevant to the theory. It is proposed that the act of destroying an object is enjoyable because it is, in effect, an aesthetic experience. The essay is divided into…

  18. Theoretical and experimental studies of a truss incorporating active members

    NASA Astrophysics Data System (ADS)

    Edberg, D. L.; Bicos, A. S.; Fuller, C. M.; Tracy, J. J.; Fechter, J. S.

    1992-04-01

    To model the behavior of the piezoelectric elements, a unique finite-element formulation of the piezoelectric struts has been developed which is based on the MSC/NASTRAN CQUAD4 element. The formulation uses the element's Poisson expansion under in-plane loading to make its behavior simulate a piezoelectric member. It is shown that the active members in the MDSSC CSI truss are useful in the investigation of a variety of vibration dissipitation and damage detection techniques.

  19. [Theoretical perspectives on medicine and the medical profession: an anthropological approach].

    PubMed

    Queiroz, M de S

    1991-08-01

    The medical field and profession are studied from the theoretical point of view of the social sciences. The most representative works on this subject are presented. The analysis shows that conservative positivism and orthodox Marxism are the main obstacles to development in this field of study. At the same time it suggests the concept of culture and the anthropological method of research as the best means for the overcoming of some of the main contradictions which paralyse its progress. PMID:1820621

  20. A theoretical perspective on the ultra-compact systems of CoRoT and Kepler

    NASA Astrophysics Data System (ADS)

    Wuchterl, G.

    2011-10-01

    CoRoT and Kepler discovered closely spaced short period planetary systems. We investigate into the physics of these systems by combining an approach that was developed for the CoRoT mission to determine the distributions of planetary masses and radii based on a minimum number of basic physical principles with the classical approach of Hill-exclusion volumes to estimate dynamical stability. We discuss to what extent the discovered systems can be understood as a random draw from the theoretical mass and/or radius distributions with Hill-exclusion stability as a constraint. We point to the bi-modality of the theoretical planetary mass-function as a key factor in shaping the architecture of the presently known systems. Given the first-time availability of new high-resolution epoch-of observation theoretical radius distributions for the entire present period sensitivity of CoRoT and Keplerreleases, we take the opportunity to confront the various radius anomalies — 'styrofoam' planets, inflated Jupiters and Neptunes — to our statistical approach.

  1. 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. PMID:18723901

  2. The default response to uncertainty and the importance of perceived safety in anxiety and stress: An evolution-theoretical perspective.

    PubMed

    Brosschot, Jos F; Verkuil, Bart; Thayer, Julian F

    2016-06-01

    From a combined neurobiological and evolution-theoretical perspective, the stress response is a subcortically subserved response to uncertainty that is not 'generated' but 'default': the stress response is 'always there' but as long as safety is perceived, the stress response is under tonic prefrontal inhibition, reflected by high vagally mediated heart rate variability. Uncertainty of safety leads to disinhibiting the default stress response, even in the absence of threat. Due to the stress response's survival value, this 'erring on the side of caution' is passed to us via our genes. Thus, intolerance of uncertainty is not acquired during the life cycle, but is a given property of all living organisms, only to be alleviated in situations of which the safety is learned. When the latter is deficient, generalized unsafety ensues, which underlies chronic anxiety and stress and their somatic health risks, as well as other highly prevalent conditions carrying such risks, including loneliness, obesity, aerobic unfitness and old age. PMID:27259803

  3. 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

  4. 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

  5. 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.

  6. 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. PMID:26412416

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

    PubMed

    McGhee, George R

    2015-12-01

    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

  8. [The role of nursing in the rehabilitation of acute stroke patients. Towards a unified theoretical perspective].

    PubMed

    Kirkevold, M

    1999-02-01

    A review of existing literature indicates an uncertainty about the specific therapeutic role of nurses in the rehabilitation of stroke patients. Two different conceptualizations of the nursing role exist, but neither is related to specific rehabilitation goals and patient outcomes. A beginning theoretical account of the specific role of nursing in stroke recovery is offered as a structure to integrate the therapeutic aspects of the coordinating, maintenance and training functions of the nurse. Existing research literature is reviewed to substantiate the account. Further research is needed to develop the specific content and focus of nursing in stroke recovery. PMID:10514744

  9. Do We Live in a Vanilla Universe? Theoretical Perspectives on WMAP

    NASA Astrophysics Data System (ADS)

    Easther, Richard

    2004-02-01

    I discuss the theoretical implications of the WMAP results, stressing WMAP's detection of a correlation between the E-mode polarization and temperature anisotropies, which provides strong support for the overall inflationary paradigm. I point out that almost all inflationary models have a ``vanilla limit,'' where their parameters cannot be distinguished from a genuinely de Sitter inflationary phase. Because its findings are consistent with vanilla inflation, WMAP cannot exclude entire classes of inflationary models. Finally, I summarize hints in the current dataset that the CMB contains relics of new physics, and the possibility that we can use observational data to reconstruct the inflaton potential.

  10. Preinduction activities: a closed malpractice claims perspective.

    PubMed

    Moody, M L; Kremer, M J

    2001-12-01

    The American Association of Nurse Anesthetists Foundation conducts an ongoing study of closed malpractice claims that involve nurse anesthetists. A team of 8 CRNA researchers has to date investigated 223 closed claim files from the St Paul Fire and Marine Insurance Company. Research findings have demonstrated that failure to provide appropriate anesthesia care relative to the Scope and Standards for Nurse Anesthesia Practice was significantly associated with adverse anesthetic outcomes. Claims that involved inadequate preinduction activities (n = 22) were analyzed in the context of their compliance with published standards of care. The largest group of claims in this analysis (59%) involved damaging respiratory events, 28% entailed damaging cardiovascular events, and the principal issue in 13% of these claims involved failure to seek available information such as laboratory studies on the medical record. The most prevalent occurrence with damaging respiratory events was undocumented airway assessment in 27% of the claims. In 55% of these claims, the medical history was not completely documented. The surgical procedure categories were general surgical (32%), obstetrical (27%), otolaryngogical (23%), orthopedic (14%), and gynecologic (5%). The involved standards of care are reviewed, and recommendations are made regarding consistent completion of preinduction activities. PMID:11837148

  11. 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

  12. 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. PMID:25046997

  13. 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

  14. The Intense Slow Positron Source concept: A theoretical perspective on a proposed INEL Facility

    SciTech Connect

    Makowitz, H.; Abrashoff, J.D.; Landman, W.H.; Albano, R.K.; Tajima, T.; Larson, J.D.

    1992-12-31

    An analysis has been performed of the INEL Intense Slow Positron Source (ISPS) concept. The results of the theoretical study are encouraging. A full-scale device with a monoenergetic 5 KeV positron beam of {ge}10{sup 12} e{sup +}/s on a {le}0.03-cmdiameter target appears feasible and can be obtained within the existing infrastructure of INEL reactor facilities. A 30.0-cm-diameter, large area source dish, moderated at first with thin crystalline W films and later by solid Ne, is proposed as the initial device in order to explore problems with a facility scale system. A demonstration scale beam at {ge}10{sup 10} slow e{sup +}/s is proposed using a {sup 58}Co source plated on a 6-cm-diameter source dish insert, placed in a 30- cm adapter.

  15. Planning and Studying Improvement in Patient Care: The Use of Theoretical Perspectives

    PubMed Central

    Grol, Richard PTM; Bosch, Marije C; Hulscher, Marlies EJL; 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. PMID:17319808

  16. Perspectives of People with Dementia About Meaningful Activities: A Synthesis.

    PubMed

    Han, Areum; Radel, Jeff; McDowd, Joan M; Sabata, Dory

    2016-03-01

    Qualitative studies were synthesized to describe perspectives of people with dementia regarding meaningful activities. Themes of connectedness were identified using a meta-ethnography approach. The theme of being connected with self encompasses engagement for continuity, health promotion, and personal time. The theme of being connected with others includes being with others not to feel alone, doing an activity with others, and meaningful relationships. The theme of being connected with the environment encompasses being connected to one’s familiar environment, community, and nature. This synthesis suggests that connectedness is an important motivation for engagement in daily activities. Findings indicate that identifying the underlying motivation for an individual with dementia to engage in different activities is important for matching a person with activities that will be satisfying. This review may inform the development of interventions for engaging people with dementia in meaningful, daily activities and creating connectedness to self, others, and the environment. PMID:26340962

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

    PubMed

    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

  18. 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

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

    SciTech Connect

    Keller, David W.

    2005-05-01

    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 (E{sub app}) to the stationary phase with respect to an external reference. The ability to monitor retention as a function of E{sub app} 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 ({Lambda}) of a solute and changes in interfacial tension (d{gamma}) as a function of both E{sub app} 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 E{sub app} 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.

  20. Senior Female Academics in the UK Academy: Theoretical Perspectives for Understanding the Impact of Education and Familial Influences on Career Success

    ERIC Educational Resources Information Center

    Hoskins, Kate

    2013-01-01

    This paper examines the theoretical perspectives I utilised in my doctoral research to uncover the role of class and gender in my respondents' stories and experiences of their career success. I argue that adopting an economic model for conceptualising the influence of social class and gender in the respondents' stories and experiences of their…

  1. Active optics for space applications: an ESA perspective

    NASA Astrophysics Data System (ADS)

    Zuccaro Marchi, Alessandro; Hallibert, Pascal; Pereira do Carmo, Joao; Wille, Eric

    2014-07-01

    Active optics for Space is relatively new field that takes advantage of lessons learnt on ground, and together with the tighter constrains of space environment it allows operation of larger mirrors apertures for space telescopes and better image quality. Technical developments are crucial to guarantee proper technological readiness for applications on new missions whose performance can be driven also by these novelties. This paper describes the philosophy pursued at ESA, providing an overview of the activities run within the Agency, as well as perspectives for new developments. The Optics Section of the Directorate of Technical and Quality Management of ESA/ESTEC is currently running three projects. Two examples are here addressed.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Tip-induced deformation of a phospholipid bilayer: theoretical perspective of sum frequency generation imaging.

    PubMed

    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. PMID:25338888

  7. Electron-neutrino scattering off nuclei from two different theoretical perspectives

    NASA Astrophysics Data System (ADS)

    Martini, M.; Jachowicz, N.; Ericson, M.; Pandey, V.; Van Cuyck, T.; Van Dessel, N.

    2016-07-01

    We analyze charged-current electron-neutrino cross sections on carbon. We consider two different theoretical approaches, on one hand the continuum random phase approximation (CRPA) which allows a description of giant resonances and quasielastic excitations, on the other hand the RPA-based calculations which are able to describe multinucleon emission and coherent and incoherent pion production as well as quasielastic excitations. We compare the two approaches in the genuine quasielastic channel, and find a satisfactory agreement between them at large energies while at low energies the collective giant resonances show up only in the CRPA approach. We also compare electron-neutrino cross sections with the corresponding muon-neutrino ones in order to investigate the impact of the different charged-lepton masses. Finally, restricting to the RPA-based approach, we compare the sum of quasielastic, multinucleon emission, coherent, and incoherent one-pion production cross sections (folded with the electron-neutrino T2K flux) with the charged-current inclusive electron-neutrino differential cross sections on carbon measured by T2K. We find a good agreement with the data. The multinucleon component is needed in order to reproduce the T2K electron-neutrino inclusive cross sections.

  8. 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.

  9. 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.

  10. 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…

  11. 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…

  12. Small-scale anisotropies of the cosmic microwave background: Experimental and theoretical perspectives

    NASA Astrophysics Data System (ADS)

    Switzer, Eric R.

    2008-06-01

    In this thesis, we consider both theoretical and experimental aspects of the cosmic microwave background (CMB) anisotropy for [cursive l] > 500. Part one addresses the process by which the universe first became neutral, its recombination history. The work described here moves closer to achieving the precision needed for upcoming small-scale anisotropy experiments. Part two describes experimental work with the Atacama Cosmology Telescope (ACT), designed to measure these anisotropies, and focuses on its electronics and software, on the site stability, and on calibration and diagnostics. Cosmological recombination occurs when the universe has cooled sufficiently for neutral atomic species to form. The atomic processes in this era determine the evolution of the free electron abundance, which in turn determines the optical depth to Thomson scattering. The Thomson optical depth drops rapidly (cosmologically) as the electrons are captured. The radiation is then decoupled from the matter, and so travels almost unimpeded to us today as the CMB. Studies of the CMB provide a pristine view of this early stage of the universe (at around 300,000 years old), and the statistics of the CMB anisotropy inform a model of the universe which is precise and consistent with cosmological studies of the more recent universe from optical astronomy. The recombination history is the largest known uncertainty in the standard cosmological model for CMB anisotropy formation. Here we investigate the formation of neutral helium during cosmological recombination and find that it is significantly different than was previously understood. We show that several new effects produce a modest (~ 0.5% at [cursive l] = 3000) change in the CMB anisotropy that should be included in the analysis of data from small-scale anisotropy experiments. These small scales contain further information from the primary CMB and from interactions of the CMB with intervening matter as it travels from the recombination era to

  13. 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.

  14. A theoretical perspective on particle acceleration by interplanetary shocks and the Solar Energetic Particle problem

    NASA Astrophysics Data System (ADS)

    Verkhoglyadova, Olga P.; Zank, Gary P.; Li, Gang

    2015-02-01

    Understanding the physics of Solar Energetic Particle (SEP) events is of importance to the general question of particle energization throughout the cosmos as well as playing a role in the technologically critical impact of space weather on society. The largest, and often most damaging, events are the so-called gradual SEP events, generally associated with shock waves driven by coronal mass ejections (CMEs). We review the current state of knowledge about particle acceleration at evolving interplanetary shocks with application to SEP events that occur in the inner heliosphere. Starting with a brief outline of recent theoretical progress in the field, we focus on current observational evidence that challenges conventional models of SEP events, including complex particle energy spectra, the blurring of the distinction between gradual and impulsive events, and the difference inherent in particle acceleration at quasi-parallel and quasi-perpendicular shocks. We also review the important problem of the seed particle population and its injection into particle acceleration at a shock. We begin by discussing the properties and characteristics of non-relativistic interplanetary shocks, from their formation close to the Sun to subsequent evolution through the inner heliosphere. The association of gradual SEP events with shocks is discussed. Several approaches to the energization of particles have been proposed, including shock drift acceleration, diffusive shock acceleration (DSA), acceleration by large-scale compression regions, acceleration by random velocity fluctuations (sometimes known as the "pump mechanism"), and others. We review these various mechanisms briefly and focus on the DSA mechanism. Much of our emphasis will be on our current understanding of the parallel and perpendicular diffusion coefficients for energetic particles and models of plasma turbulence in the vicinity of the shock. Because of its importance both to the DSA mechanism itself and to the particle

  15. AB033. Comparing male and female sexual arousal, utilizing fMRI: a theoretical perspective

    PubMed Central

    Banner, Linda L.

    2015-01-01

    responses, and brain activation were all correlated with the kind of stimuli they were receiving at the time. Results After a block analysis data assessment, the results demonstrated the young men had sexual arousal activation: in the right subinsular region, including the claustrum, left caudate and putamen, right middle occipital/middle temporal gyri, bilateral cingulated gyrus and right sensiormotor and pre-motor regions. This was in contrast to the female results, which demonstrated more behavioral response to the erotic stimuli by the NHSD women. Additionally, women with NHSD showed more activation in the bilateral entorhinal cortex. And, women with HSDD showed more activation in the medial frontal gyrus (Broadman Area-BA10), right inferior frontal gyrus (BA 47) and bilateral putamen. Findings were consistent across three experimental sessions. The results suggest differences between NHSD and HSDD women in encoding sexual stimuli, retrieval of past erotic experiences or both. Conclusions While this presentation demonstrates gender differences of sexual arousal in brain activation, clearly, there is more work to be done to define the science behind the hypotheses. Some additional hypotheses to be explored might include: comparing male and female sexual arousal with fMRI technology across the lifespan; and, with various diseases and disorders. Once the science is defined, we might be able to more effectively understand the etiology and efficacy of various treatment methods for various diseases and disorders.

  16. 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. PMID:27012986

  17. Packing, Scheduling and Covering Problems in a Game-Theoretic Perspective

    NASA Astrophysics Data System (ADS)

    Karlstrom, Leif

    Magma transport pathways through Earth's crust span 12--15 orders of magnitude in time and space, with unsteadiness at all scales. However emergent organization of this system is widespread, recorded by spatial loci of volcanism at the surface and large-scale, rapid outpourings of magma throughout the geologic record. This thesis explores several mechanisms for the organization and time evolution of magma transport, from the deep crust to the surface. A primary focus (Chapters 2--5) is the filling, stability and drainage of magma chambers, structures which function both as reservoirs feeding individual volcanic eruptions and as stalling points in the crust where magma accumulates and differentiation occurs. We show that magma chambers may dictate the spatio-temporal organization of magma rising through crust (Chapters 2--3), control the surface eruptive progression of extreme mantle melting events (Chapter 4), and actively set the size of calderas that form during shallow, crystal rich eruptions (Chapter 5). Each of these chapters explores variations on a hypothesis: interactions between magma chamber stresses and the rheology of surrounding crustal materials evolve during magma transport and this unsteady process helps determine the magnitude, location, and timing of surface eruptions. The last part of this thesis (Chapters 6--7) focuses on surface transport processes, the meandering of melt channels on the surface of glaciers and lava flows. We show that the meandering instability is a generic feature of flow over an erodable substrate, despite significantly different fluid characteristics and erosion mechanics.

  18. 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.

  19. Theoretical studies on CuCl-catalyzed C-H activation/C-O coupling reactions: oxidant and catalyst effects.

    PubMed

    Zhang, Lu-Lu; Li, Shi-Jun; Zhang, Lei; Fang, De-Cai

    2016-05-11

    Copper-complex catalyzed coupling reactions have been widely applied in the production of many important organic moieties from a synthetic perspective. In this work, a series of density functional theory (DFT) calculations, employing the B3LYP + IDSCRF/DZVP method, have been performed for a typical CuCl-catalyzed C-O cross-coupling reaction. The novel reaction mechanism was reported as four successive processes: oxidative radical generation (ORG) or oxidative addition (OA), hydrogen abstraction (HA), C-H activation/reductive elimination, and separation of product and recycling of catalyst (SP & RC). Our calculations provided a deep understanding on the dissimilar chemical activities associated with varying the oxidants used; detailed energy profile analyses suggested that the first oxidation process could proceed via either of the two competing channels (ORG and OA mechanisms) which is the basis to explain the different experimental yields. In addition, our molecular modelling gave theoretical evidence that Cu(ii) → Cu(i) reduction by solvent DMF (and a water molecule) might serve as a preliminary step to produce some more active Cu(i) species that could subsequently be oxidized into Cu(iii) favorably. In contrast, the Cu(ii) → Cu(iii) direct pathway was estimated to be prohibited from thermodynamics. All the calculation results in this work are parallel with the experimental observations. PMID:27088885

  20. 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…

  1. Conceptualizing a Theoretical Model for School-Centered Adolescent Physical Activity Intervention Research

    ERIC Educational Resources Information Center

    Chen, Ang; Hancock, Gregory R.

    2006-01-01

    Adolescent physical inactivity has risen to an alarming rate. Several theoretical frameworks (models) have been proposed and tested in school-based interventions. The results are mixed, indicating a similar weakness as that observed in community-based physical activity interventions (Baranowski, Lin, Wetter, Resnicow, & Hearn, 1997). The…

  2. 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

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

    PubMed

    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 of "variational

  4. 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.

  5. 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...

  6. Exergames: Theoretical Perspective.

    PubMed

    Thompson, Debbe

    2015-02-01

    This article is based on an invited presentation for the Exergame Preconference Symposium held in Houston, TX, May 19-20, 2014 that was hosted by Tom Baranowski, PhD, and the U.S. Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Baylor College of Medicine. Its purpose is to provide insight into the ways in which theory can be used to guide exergame research. PMID:26181674

  7. 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

  8. 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.

  9. Active case finding of tuberculosis: historical perspective and future prospects

    PubMed Central

    Golub, J. E.; Mohan, C. I.; Comstock, G. W.; Chaisson, R. E.

    2015-01-01

    SUMMARY Despite a history of remarkable scientific achievements in microbiology and therapeutics, tuberculosis (TB) continues to pose an extraordinary threat to human health. Case finding and treatment of TB disease are the principal means of controlling transmission and reducing incidence. This review presents a historical perspective of active case finding (ACF) of TB, detailing case detection strategies that have been used over the last century. This review is divided into the following sections: mass radiography, house-to-house surveys, out-patient case detection, enhanced case finding, high-risk populations and cost-effectiveness. The report concludes with a discussion and recommendations for future case finding strategies. Understanding the strengths and weaknesses of these methods will help inform and shape ACF as a TB control policy in the twenty-first century. PMID:16333924

  10. Theoretical Perspectives Concerning Positive Aspects of Caring for Elderly Persons with Dementia: Stress/Adaptation and Existentialism.

    ERIC Educational Resources Information Center

    Farran, Carol J.

    1997-01-01

    Uses an existentialist perspective to examine the current empirical stress/adaptation model that guides caregiving of persons with dementia. Compares and contrasts key elements, strengths, and limitations of each model and isolates areas of convergence/divergence in both perspectives. Identifies implications for future theory development,…

  11. 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…

  12. A combined experimental and theoretical study of the thermal cycloaddition of aryl azides with activated alkenes.

    PubMed

    Zeghada, Sarah; Bentabed-Ababsa, Ghenia; Derdour, Aïcha; Abdelmounim, Safer; Domingo, Luis R; Sáez, José A; Roisnel, Thierry; Nassar, Ekhlass; Mongin, Florence

    2011-06-01

    Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the β-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower activation energy). The effect of non-conventional activation methods on the degradation of 1,2,3-triazolines was next studied experimentally. Finally, some of the 1,2,3-triazoles such synthesized were evaluated for their bactericidal and cytotoxic activities. PMID:21494704

  13. Physical Activity Behaviour: An Overview of Current and Emergent Theoretical Practices

    PubMed Central

    Buchan, Duncan S.; Ollis, Stewart; Thomas, Non E.; Baker, Julien S.

    2012-01-01

    Physical activity research has been dominated by traditional cognitive rationale paradigms utilized within other domains. Though this approach to physical activity behavior has greatly enhanced our understanding of the key determinants, it has done little to eradicate the health problems we currently face. In order to achieve lasting change though, multilevel interventions may prove effective. Ecological perspectives have been proposed as an effective approach in combating current physical inactivity levels. Nevertheless, this approach is in its infancy and much has still to be learned. The aim of this paper is to provide an overview of the main behavioral models used within the physical activity domain while proposing the need for further models that will embrace the principles presented by ecological and complexity theories. PMID:22778918

  14. [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. PMID:26378756

  15. 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. PMID:25286989

  16. Active surveillance for prostate cancer: a legal perspective.

    PubMed

    Venderbos, Lionne Df; Roobol, Monique J; de Hoogh, August Nl

    2014-01-01

    Active surveillance (AS) for prostate cancer (PCa) has become a viable management strategy for men with low-risk PCa. With AS being offered more often and more patients being included in AS studies, the aim of this paper is to describe AS from a legal perspective. What might be pitfalls in the management strategy that urologists should be aware of? In order to construct an answer to our research question, a patient from the Prostate cancer Research International: Active Surveillance (PRIAS) study will be used as an example. In the methods section, first some information on the PRIAS study is given. Then a PRIAS case will be described after which the Dutch legal framework will be set-out. Finally, the Dutch legal framework will be applied to the PRIAS case to find what would happen if that particular patient would file a complaint. On the basis of the analysis we can conclude that urologists that offer AS should be aware of the information that they provide to patients when entering AS but also during follow-up. It is furthermore important that urologists act in line with their medical professional standards. Therefore it is advised that urologists follow the progress that is made within the field of AS carefully, as the field is moving rapidly. PMID:25606578

  17. Active surveillance for prostate cancer: a legal perspective

    PubMed Central

    Venderbos, Lionne DF; Roobol, Monique J; de Hoogh, August NL

    2014-01-01

    Active surveillance (AS) for prostate cancer (PCa) has become a viable management strategy for men with low-risk PCa. With AS being offered more often and more patients being included in AS studies, the aim of this paper is to describe AS from a legal perspective. What might be pitfalls in the management strategy that urologists should be aware of? In order to construct an answer to our research question, a patient from the Prostate cancer Research International: Active Surveillance (PRIAS) study will be used as an example. In the methods section, first some information on the PRIAS study is given. Then a PRIAS case will be described after which the Dutch legal framework will be set-out. Finally, the Dutch legal framework will be applied to the PRIAS case to find what would happen if that particular patient would file a complaint. On the basis of the analysis we can conclude that urologists that offer AS should be aware of the information that they provide to patients when entering AS but also during follow-up. It is furthermore important that urologists act in line with their medical professional standards. Therefore it is advised that urologists follow the progress that is made within the field of AS carefully, as the field is moving rapidly. PMID:25606578

  18. Theoretical research into anticancer activity of diterpenes isolated from the paraiban flora.

    PubMed

    Ishiki, Hamilton; Junior, Francisco J B Mendonça; Santos, Paula F; Tavares, Josean F; Tavares, Josean F; Silva, Marcelo S; Scotti, Marcus T

    2014-07-01

    Many studies of the scientific literature discuss the anticancer activity of diterpenes inhibiting the Akt/IKK/NF-kappaB pro-survival signaling cascade, mainly by the activation of serine/threonine phosphatase PP2A. The aim of this work was to evaluate and compare the anticancer potential of three atisane, three kaurane and three trachylobane diterpenes extracted from the roots of Xylopia langsdorffiana. Thus, we investigated the reactivity (H-L(GAP) parameter), HOMO atmosphere favorable to neutralize the radical reactivity, and the docking of compounds with PP2A. With all approaches, this theoretical study showed that atisane diterpenes have favorable characteristics for antitumor activity, like electron donating ability and greater hydrophilic interactions with the enzyme, by inhibition of Akt/IKK/NF-kappaB, and activation of PP2A. PMID:25230491

  19. Solid state structural and theoretical investigations of a biologically active chalcone

    NASA Astrophysics Data System (ADS)

    Abbas, Asghar; Gökce, Halil; Bahceli, Semiha; Bolte, Michael; Naseer, Muhammad Moazzam

    2016-05-01

    The computational methods are presently emerging as an efficient and reliable tool for predicting structural properties of biologically important compounds. In the present manuscript, the solid state structural and theoretical investigations of a biologically active chalcone i-e (E)-3-(4-(hexyloxy)phenyl)-1-phenylprop-2-en-1-one (6c) have been reported. The solid state structure of 6c was measured by X-ray crystallographic technique whereas the optimized molecular geometry, vibrational frequencies, the simulated UV-vis spectra (in gas and in methanol solvent), 1H and 13C NMR chemical shift (in gas and in chloroform solvent) values, HOMO-LUMO analysis, the molecular electrostatic potential (MEP) surface and thermodynamic parameters were calculated by using DFT/B3LYP method with 6-311++G(d,p) basis set in ground state. The results of the theoretical investigations were found to be in good agreement with experimental data.

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

    PubMed

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

    2014-01-01

    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 DPPH assay. Further analysis is carried out with successive extracts of leaves of varying polarity of solvents. In DPPH 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 (1)HNMR). 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 OH 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. PMID:24398157

  1. 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.

  2. Centering Perspectives on Black Women, Hair Politics, and Physical Activity

    PubMed Central

    Versey, H. Shellae

    2014-01-01

    As researchers categorize issues facing Black women’s health, obesity and physical exercise continue to be significant topics of debate. General interventions targeted toward Black women to address obesity and increase physical exercise have been largely ineffective. In this article, I situate the current public health discourse on obesity and related interventions within a sociocultural context of body appearance, with a specific focus on hair. Why do some African American women feel such strong ties to their hair that they will avoid exercise? What can be done to understand this phenomenon and address alternatives that may make both hair maintenance and regular exercise feasible? I map a theoretical argument for why hair matters for some women, and discuss how physical activity intervention strategies might be improved by considering such complexities. PMID:24625146

  3. 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…

  4. 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…

  5. 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…

  6. Physical activity promotion in call centres: employers' perspectives.

    PubMed

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

    2011-12-01

    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 were conducted with 15 managers in 10 of 12 local CCs and questionnaires were used to collect quantitative information about participants and their workplaces. Thematic analysis revealed that participants' responses to recommendations for PA promotion were generally positive and some CCs were engaged in some PA initiatives. Employers' motivations to promote PA included direct benefits to the employer, concern for employee well-being and the greater good. Barriers to PA promotion within CCs included the nature of CC work, managers' concerns regarding participation, fairness and cost and special limitations of the workspace. Results indicate additional actions and supports are required to facilitate implementation of PA in CCs according to governmental recommendations. Efforts are required to increase awareness and use of existing resources. Smaller organizations may require more assistance to promote PA than those with a larger number of employees and may benefit from enhanced interaction with existing networks and public health programs and resources. PMID:21712500

  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. 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. PMID:26094083

  9. 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.

  10. 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).

  11. Si-H activation in an iridium nitrido complex--a mechanistic and theoretical study.

    PubMed

    Sieh, Daniel; Burger, Peter

    2013-03-13

    Si-H activation in triethyl- and triarylsilanes by a square-planar pyridine-diimine iridium complex with a terminal nitrido unit leads to the corresponding silyl amido complexes, which were unambiguously characterized by X-ray crystallography. Based on detailed combined kinetic and theoretical studies (DFT), direct addition of the Si-H bond to the iridium nitrido unit is proposed. The electronic propensities of the transition states for the Si-H activation were probed with a Hammett series of para-substituted triarylsilanes HSi(C6H5)2(4-C6H4-X). Based on the combination of experimental and theoretical studies, two independent pathways for this process are proposed, which point toward an ambiphilic propensity of the nitrido unit. Alternative pathways and the charge transfer in the transition states were also investigated. Furthermore, the barriers for the related H-H and C-H activation processes in dihydrogen and methane were analyzed. PMID:23431955

  12. Theoretical study of thermally activated magnetization switching under microwave assistance: Switching paths and barrier height

    NASA Astrophysics Data System (ADS)

    Suto, H.; Kudo, K.; Nagasawa, T.; Kanao, T.; Mizushima, K.; Sato, R.; Okamoto, S.; Kikuchi, N.; Kitakami, O.

    2015-03-01

    Energy barrier height for magnetization switching is theoretically studied for a system with uniaxial anisotropy in a circularly polarized microwave magnetic field. A formulation of the Landau-Lifshitz-Gilbert equation in a rotating frame introduces an effective energy that includes the effects of both the microwave field and static field. This allows the effective-energy profiles to rigorously describe the switching paths and corresponding barrier height, which govern thermally activated magnetization switching under microwave assistance. We show that fixed points and limit cycles in the rotating frame lead to various switching paths and that under certain conditions, switching becomes a two-step process with an intermediate state.

  13. Theoretical insights on the antioxidant activity of edaravone free radical scavengers derivatives

    NASA Astrophysics Data System (ADS)

    Cerón-Carrasco, José P.; Roy, Hélène M.; Cerezo, Javier; Jacquemin, Denis; Laurent, Adèle D.

    2014-04-01

    The prediction of antioxidant properties is not straightforward due to the complexity of the in vivo systems. Here, we use theoretical descriptors, including the potential of ionization, the electrodonating power and the spin density distribution, to characterize the antioxidant capacity of edaravone (EDV) derivatives. Our computations reveal the relationship between these parameters and their potential bioactivity as free radical scavengers. We conclude that more efficient antioxidants could be synthesized by tuning the R1 and R2 positions of the EDV structure, rather than modifying the R3 group. Such modifications might improve the antioxidant activity in neutral and deprotonated forms.

  14. 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.

  15. Theoretical models for cooperative steady-state ATPase activity of myosin subfragment-1 on regulated actin.

    PubMed Central

    Hill, T L; Eisenberg, E; Chalovich, J M

    1981-01-01

    Recent theoretical work on the cooperative equilibrium binding of myosin subfragment-1-ADP to regulated actin, as influenced by Ca2+, is extended here to the cooperative steady-state ATPase activity of myosin subfragment-1 on regulated actin. Exact solution of the general steady-state problem will require Monte Carlo calculations. Three interrelated special cases are discussed in some detail and sample computer (not Monte Carlo) solutions are given. The eventual objective is to apply these considerations to in vitro experimental data and to in vivo muscle models. PMID:6455170

  16. Synthesis, structure, theoretical calculations and biological activity of sulfonate active ester new derivatives

    NASA Astrophysics Data System (ADS)

    Ghazzali, Mohamed; Khattab, Sherine A. N.; Elnakady, Yasser A.; Al-Mekhlafi, Fahd A.; Al-Farhan, Khalid; El-Faham, Ayman

    2013-08-01

    A series of naphthyl and tolyl sulfonate ester were synthesized and characterized by H NMR. X-ray single crystal diffraction experiments established the molecular structure of three new sulfonate esters derivatives, and spectral data agree with these in solution. The observed hydrogen bonding is discussed on the basis of crystal structural analyses and DFT/MP2 geometry optimization quantum calculations. Antimicrobial activities were screened for selected compounds against three human cancer cell lines and Mosquito Culex pipiens larvae.

  17. Theoretical study of nitrodibenzofurans: A possible relationship between molecular properties and mutagenic activity.

    PubMed

    Stanković, B; Ostojić, B D; Popović, A; Gruden, M А; Đorđević, D S

    2016-11-15

    In this study we present a theoretical investigation of the molecular properties of nitrodibenzofurans (NDFs) and dinitrodibenzofurans (DNDFs) and their relation to mutagenic activity. Equilibrium geometries, relative energies, vertical ionization potentials (IP), vertical electron activities (EA), electronic dipole polarizabilities, and dipole moments of all NDFs and three DNDFs calculated by Density Functional Theory (DFT) methods are reported. The Ziegler/Rauk Energy Decomposition Analysis (EDA) is employed for a direct estimate of the variations of the orbital interaction and steric repulsion terms corresponding to the nitro group and the oxygen of the central ring of NDFs. The results indicate differences among NDF isomers for the cleavage of the related bonds and steric effects in the active site. The results show a good linear relationship between polarizability (<α>), anisotropy of polarizability (Δα), the summation of IR intensities (ΣIIR) and the summation of Raman activities (ΣARaman) over all 3N-6 vibrational modes and experimental mutagenic activities of NDF isomers in Salmonella typhimurium TA98 strain. The polarizability changes with respect to the νsNO+CN vibrational mode are in correlation with the mutagenic activities of NDFs and suggest that intermolecular interactions are favoured along this coordinate. PMID:27475460

  18. 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.

  19. 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'…

  20. 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,…

  1. Increased oxygen consumption following activation of brain: theoretical footnotes using spectroscopic data from barrel cortex.

    PubMed

    Mayhew, J; Johnston, D; Martindale, J; Jones, M; Berwick, J; Zheng, Y

    2001-06-01

    Optical imaging spectroscopy (OIS) and laser Doppler flowmetry (LDF) data sequences from anesthetized rats were used to determine the relationship between changes in oxy-and deoxygenated hemoglobin concentration and changes in blood volume and flow in the presence and absence of stimulation. The data from Jones et al. (accompanying paper) were used to explore the differences between two theoretical models of flow activation coupling. The essential difference between the two models is the extension of the model of Buxton and Frank by Hyder et al. (1998, J. Appl. Physiol. 85: 554--564) to incorporate change in capillary diffusivity coupled to flow. In both models activation-increased flow changes increase oxygen transport from the capillary; however, in Hyder et al.'s model the diffusivity of the capillary itself is increased. Hyder et al. proposed a parameter (Omega), a scaling "constant" linking increased blood flow and oxygen "diffusivity" in the capillary bed. Thus, in Buxton and Frank's theory, Omega = 0; i.e., there are no changes in diffusivity. In Hyder et al.'s theory, 0 < Omega < 1, and changes in diffusivity are assumed to be linearly related to flow changes. We elaborate the theoretical position of both models to show that, in principle, the different predictions from the two theories can be evaluated using optical imaging spectroscopy data. We find that both theoretical positions have limitations when applied to data from brief stimulation and when applied to data from mild hypercapnia. In summary, the analysis showed that although Hyder et al.'s proposal that diffusivity increased during activation did occur; it was shown to arise from an implementation of Buxton and Frank's theory under episodes of brief stimulation. The results also showed that the scaling parameter Omega is not a constant as the Hyder et al. model entails but in fact varies over the time course of the flow changes. Data from experiments in which mild hypercapnia was administered also

  2. Hierarchical representations of the five-factor model of personality in predicting job performance: integrating three organizing frameworks with two theoretical perspectives.

    PubMed

    Judge, Timothy A; Rodell, Jessica B; Klinger, Ryan L; Simon, Lauren S; Crawford, Eean R

    2013-11-01

    Integrating 2 theoretical perspectives on predictor-criterion relationships, the present study developed and tested a hierarchical framework in which each five-factor model (FFM) personality trait comprises 2 DeYoung, Quilty, and Peterson (2007) facets, which in turn comprise 6 Costa and McCrae (1992) NEO facets. Both theoretical perspectives-the bandwidth-fidelity dilemma and construct correspondence-suggest that lower order traits would better predict facets of job performance (task performance and contextual performance). They differ, however, as to the relative merits of broad and narrow traits in predicting a broad criterion (overall job performance). We first meta-analyzed the relationship of the 30 NEO facets to overall job performance and its facets. Overall, 1,176 correlations from 410 independent samples (combined N = 406,029) were coded and meta-analyzed. We then formed the 10 DeYoung et al. facets from the NEO facets, and 5 broad traits from those facets. Overall, results provided support for the 6-2-1 framework in general and the importance of the NEO facets in particular. PMID:24016206

  3. Theoretical investigation on antioxidant activity of vitamins and phenolic acids for designing a novel antioxidant

    NASA Astrophysics Data System (ADS)

    Mohajeri, Afshan; Asemani, S. Somayeh

    2009-07-01

    Theoretical calculations have been performed to predict antioxidant property for two interesting classes of compounds including phenolic acids and vitamins. Important characteristics of antioxidants such as O-H bond dissociation enthalpy (BDE) and ionization potential (IP) were calculated in the gas-phase to analyze the effect of heterocyclic ring, intramolecular hydrogen bonding and presence of electron donating group near the O-H on the antioxidant activity. The results reveal that the presence of intramolecular hydrogen bonding through ortho-hydroxy group lowers BDE, IP and spin density. In general, phenolic acids were found to be more effective antioxidant than vitamins. The H-atom transfer (HAT) mechanism was selected to study the hydrogen abstraction from phenolic compounds by hydroperoxyl radical. It is found that the antioxidant with lower BDE undergoes hydrogen abstraction with low barrier and considerable exothermicity. On the basis of these results we were able to design a novel antioxidant with enhanced activity.

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

    PubMed Central

    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. PMID:26175677

  5. 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.

  6. 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

    2015-01-01

    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. PMID:26035095

  7. CALL and the Development of Learner Autonomy: Towards an Activity-Theoretical Perspective

    ERIC Educational Resources Information Center

    Blin, Francoise

    2004-01-01

    While the concepts and principles associated with learner autonomy underpin a broad range of CALL applications and research projects, current debates and research paradigms in CALL do not provide adequate tools and models to investigate in depth the relationship between CALL and the development of learner autonomy. This paper explores the…

  8. Evaluating the Theoretical Content of Online Physical Activity Information for People with Multiple Sclerosis

    PubMed Central

    Baillie, Colin P.T.; Galaviz, Karla; Jarvis, Jocelyn W.; Latimer-Cheung, Amy E.

    2015-01-01

    Background: Physical activity can aid people with multiple sclerosis (MS) in managing symptoms and maintaining functional abilities. The Internet is a preferred source of physical activity information for people with MS and, therefore, a method for the dissemination of behavior change techniques. The purpose of this study was to examine the coverage and quality of physical activity behavior change techniques delivered on the Internet for adults with MS using Abraham and Michie's taxonomy of behavior change techniques. Methods: Using the taxonomy, 20 websites were coded for quality (ie, accuracy of information) and coverage (ie, completeness of information) of theoretical behavior change techniques. Results: Results indicated that most websites covered a mean of 8.05 (SD 3.86, range 3–16) techniques out of a possible 20. Only one of the techniques, provide information on behavior–health link and consequences, was delivered on all websites. The websites demonstrated low mean coverage and quality across all behavior change techniques, with means of 0.64 (SD 0.67) and 0.62 (SD 0.37) on a scale of 0 to 2, respectively. However, coverage and quality improved when websites were examined solely for the techniques that they covered, as opposed to all 20 techniques. Conclusions: This study, which examined quality and coverage of physical activity behavior change techniques described online for people with MS, illustrated that the dissemination of these techniques requires improvement. PMID:25892979

  9. Perspectives.

    ERIC Educational Resources Information Center

    Robertson, Shari; Camerini, Michael

    2001-01-01

    Provides background information on the U.S. Immigration and Naturalization Service Asylum office. Uses the perspective of two movie producers as they filmed a documentary film, "Well-founded Fear", about asylum and refugee protection. Includes information on how to order a classroom aid and the film. (CMK)

  10. 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…

  11. 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…

  12. 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…

  13. A Theoretical Review of Winne and Hadwin's Model of Self-Regulated Learning: New Perspectives and Directions

    ERIC Educational Resources Information Center

    Greene, Jeffrey Alan; Azevedo, Roger

    2007-01-01

    This theoretical review of Winne and Hadwin's model of self-regulated learning (SRL) seeks to highlight how the model sheds new light on current research as well as suggests interesting new directions for future work. The authors assert that the model's more complex cognitive architecture, inclusion of monitoring and control within each phase of…

  14. Watchfully checking rapport with the Primary Child Health Care nurses - a theoretical model from the perspective of parents of foreign origin

    PubMed Central

    2010-01-01

    Background Worldwide, multicultural interaction within health care seems to be challenging and problematic. This is also true among Primary Child Health Care nurses (PCHC nurses) in the Swedish Primary Child Health Care services (PCHC services). Therefore, there was a need to investigate the parents' perspective in-depth. Aim The aim of the study was to construct a theoretical model that could promote further understanding of the variety of experiences of parents of foreign origin regarding their interaction with the PCHC nurses at PCHC services. Method The study used Grounded Theory Methodology. Twenty-one parents of foreign origin in contact with PCHC servicies were interviewed. Results In our study parents were watchfully checking rapport, i.e. if they could perceive sympathy and understanding from the PCHC nurses. This was done by checking the nurse's demeanour and signs of judgement. From these interviews we created a theoretical model illustrating the interactive process between parents and PCHC nurses. Conclusion We found it to be of utmost importance for parents to be certain that it was possible to establish rapport with the PCHC nurse. If not, disruptions in the child's attendance at PCHC services could result. PCHC nurses can use the theoretical model resulting from this study as a basis for understanding parents, avoiding a demeanour and judgements that may cause misunderstandings thus promoting high-quality interaction in PCHC services. PMID:20646287

  15. 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…

  16. Theoretical and experimental activities on opacities for a good interpretation of seismic stellar probes

    NASA Astrophysics Data System (ADS)

    Turck-Chièze, S.; Loisel, G.; Gilles, D.; Thais, F.; Bastiani, S.; Blancard, C.; Busquet, M.; Caillaud, T.; Cosse, P.; Blenski, T.; Delahaye, F.; Educret, J.; Faussurier, G.; Gilleron, F.; Guzik, J.; Harris, J. W.; Kilcrease, D. P.; Magee, N. H.; Piau, L.; Pain, J. C.; Poirier, M.; Porcherot, Q.; Reverdin, C.; Silvert, V.; Villette, B.; Zeippen, C.

    2011-01-01

    Opacity calculations are basic ingredients of stellar modelling. They play a crucial role in the interpretation of acoustic modes detected by SoHO, COROT and KEPLER. In this review we present our activities on both theoretical and experimental sides. We show new calculations of opacity spectra and comparisons between eight groups who produce opacity spectra calculations in the domain where experiments are scheduled. Real differences are noticed with real astrophysical consequences when one extends helioseismology to cluster studies of different compositions. Two cases are considered presently: (1) the solar radiative zone and (2) the beta Cephei envelops. We describe how our experiments are performed and new preliminary results on nickel obtained in the campaign 2010 at LULI 2000 at Polytechnique.

  17. Kindergarten Children's Involvement in Early Literacy Activities: Perspectives from Europe.

    ERIC Educational Resources Information Center

    Shiel, Gerry

    2002-01-01

    Focuses on early childhood literacy education and the perspectives offered by some European presenters at the 12th European Conference on Reading. Describes an ego-based literacy simulation for at-risk preschoolers from Norway; an early literacy support program for at-risk beginning readers from Slovakia; and a pre-kindergarten children's…

  18. Queering Student Perspectives: Gender, Sexuality and Activism in School

    ERIC Educational Resources Information Center

    Elliott, Kathleen O.

    2016-01-01

    This paper examines the work of a gay-straight alliance and the ways in which members use elements of queer theory to understand their own and others' identities, both to make sense of their experiences and to support their activist efforts. The analysis identifies queer perspectives on gender and sexual identity as useful tools for supporting…

  19. 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.

  20. 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…

  1. Participation in Peer Response as Activity: An Examination of Peer Response Stances from an Activity Theory Perspective

    ERIC Educational Resources Information Center

    Zhu, Wei; Mitchell, Deborah A.

    2012-01-01

    This article reports a case study that examined English as a Second Language students' peer response stances from an activity theory perspective. More specifically, the study was guided by the constructs of activity and motive/object in Leont'ev's theory. Multiple sources of data were collected from two native Spanish-speaking students enrolled in…

  2. 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.

  3. 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…

  4. Passive and active protection from ionizing radiation in space: new activities and perspectives.

    NASA Astrophysics Data System (ADS)

    Spillantini, Piero

    Very intense Solar Cosmic Ray (SCR) events are rare, but not predictable, and can be lethal to a not protected crew in deep space. A ‘life saving’ system must therefore be provided also in short duration manned missions. Passive and active ‘life saving’ system will be revised and discussed. Galactic Cosmic Rays (GCR) instead flow continuously, have a moderate intensity but the accumulation of their effects can have consequences to human health in long duration (≥one year) mission in deep space, and a ‘health saving’ system should be provided. Passive systems are not applicable and recourse has to be made to active systems based on powerful magnetic fields for deviating particles from the habitat where crew members live and work. The activities of last decade are revised and two scenarios are evaluated and discussed: (1) magnetic toroidal systems for mitigating the radiation dose in the relatively large (≅100m3) habitat of interplanetary spaceships; (2) very large magnetic systems for protecting a large habitat (≈500m3) of an inhabited station that should operate for many decades in deep space. Effectiveness, complexity, involved engineering problems and perspectives are outlined and discussed for both the scenarios. They are nowadays studied and evaluated by a cooperative project supported by the European Union that will be illustrated in a dedicated talk.

  5. Critical and Theoretical Perspective on Scapular Stabilization: What Does It Really Mean, and Are We on the Right Track?

    PubMed

    McQuade, Kevin J; Borstad, John; de Oliveira, Anamaria Siriani

    2016-08-01

    Stabilization exercises have been a focus and mainstay of many therapeutic and performance training programs in the past decade. Whether the focus is core stabilization for the spine or scapular stabilization, clinicians and trainers alike have endorsed these programs, largely on the basis of conceptual theory and anecdotal experience. The notion that an unstable scapula is related to shoulder dysfunction and pathology is well accepted, but is it accurate? The aim of this perspective article is to challenge the concept of scapular stabilization through the application of biomechanical and motor control constructs. The objectives are to critically examine current beliefs about scapular stabilization, to discuss definitions of stabilization and stability in the context of the scapulothoracic region, and to evaluate key evidence regarding scapular stabilization and scapular dyskinesia. Several new approaches that may affect the understanding of normal and atypical scapula motion are explored. Finally, a historical analogy is presented and future research and clinical directions are suggested. The aims are to lead readers to the essential concepts implied on scapular stabilization, to increase the critical thought process in rehabilitation practice, and to suggest some open topics to be explored in future research. PMID:26847012

  6. 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.

  7. 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)

  8. Theoretical Study on Benzazole Derivatives for Use in Blue Thermally Activated Delayed Fluorescence Emitters.

    PubMed

    Kwon, Dong Yuel; Lee, Geon Hyeong; Kim, Young Sik

    2015-10-01

    Four novel thermally activated delayed fluorescence (TADF) materials with 9,10-dihydro-9,9-dimethylacridine (DMAC) and phenylindolo(2,3-a)carbazole (PIC) as electron donors and benzazole derivatives (BO, and BT) as electron acceptors (DMAC-BO, DMAC-BT, PIC-BO, and PIC-BT) were designed and theoretically investigated for use as a blue organic light emitting diode (OLED) emitter. Using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations, we calculated the electron distribution of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), and the energy of the lowest singlet (S1) and the lowest triplet (T1) excited states. All the dyes had a small spatial overlap between the HOMO and LUMO because of the relatively large dihedral angle between the phenyl ring and the acceptor moiety. In terms of the energy difference (ΔEST) between the S1 state and the T1 state, DMAC-BO and DMAC-BT showed the small ΔEST (0.18 eV and 0.21 eV, respectively). However, PIC-BO and PIC-BT showed the large ΔEST (0.62 eV and 0.61 eV, respectively). Among the TADF materials, we showed that DMAC-BO would have the best TADF properties in terms of small ΔEST and blue OLED emitters. PMID:26726420

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

    NASA Technical Reports Server (NTRS)

    Han, H. C.; Kong, J. A.; Shin, R. T.; Nghiem, S. 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 used to calculate the effective permittivity and the distorted Born approximation is used to obtain the polarimetric scattering coefficients. Thermal emissions based on the reciprocity and energy conservation principles are calculated. The effects of the random roughness at the air-ice, and ice-water interfaces are explained by adding the surface scattering to the volume scattering return incoherently. The theoretical model, which has been successfully applied to analyze the radar backscatter data of first-year sea ice, is used to interpret the measurements performed in the Cold Regions Research and Engineering Laboratory's CRRELEX program.

  10. 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.

  11. Perspectives of experimental and theoretical studies of self-organized dust structures in complex plasmas under microgravity conditions

    NASA Astrophysics Data System (ADS)

    Tsytovich, V. N.

    2015-02-01

    We review research aimed at understanding the phenomena occurring in a complex plasma under microgravity conditions. Some aspects of the work already performed are considered that have not previously been given sufficient attention but which are potentially crucial for future work. These aspects, in particular, include the observation of compact dust structures that are estimated to be capable of confining all components of a dust plasma in a bounded spatial volume; experimental evidence of the nonlinear screening of dust particles; and experimental evidence of the excitation of collective electric fields. In theoretical terms, novel collective attraction processes between likely charged dust particles are discussed and all schemes of the shadowy attraction between dust particles used earlier, including in attempts to interpret observations, are reviewed and evaluated. Dust structures are considered from the standpoint of the current self-organization theory. It is emphasized that phase transitions between states of self-organized systems differ significantly from those in homogeneous states and that the phase diagrams should be constructed in terms of the parameters of a self-organized structure and cannot be constructed in terms of the temperature and density or similar parameters of homogeneous structures. Using the existing theoretical approaches to modeling self-organized structures in dust plasmas, the parameter distribution of a structure is recalculated for a simpler model that includes the quasineutrality condition and neglects diffusion. These calculations indicate that under microgravity conditions, any self-organized structure can contain a limited number of dust particles and is finite in size. The maximum possible number of particles in a structure determines the characteristic inter-grain distance in dust crystals that can be created under microgravity conditions. Crystallization criteria for the structures are examined and the quasispherical

  12. 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

  13. 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

  14. 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…

  15. 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…

  16. 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 not to…

  17. 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…

  18. Toward Broader Perspectives of Young Children's Mathematics: Recognizing and Comparing Olivia's Beliefs and Activity

    ERIC Educational Resources Information Center

    Wernet, Jamie L; Nurnberger-Haag, Julie

    2015-01-01

    Little research exists on young children's beliefs about mathematics, and current research perspectives on early mathematical activity may overlook a great deal of young children's sophisticated mathematical thinking. We argue this is attributable, in part, to a need for a broader view of what mathematics is, including cultural practices that are…

  19. 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.

  20. Antioxidant activity, NMR, X-ray, ECD and UV/vis spectra of (+)-terrein: Experimental and theoretical approaches

    NASA Astrophysics Data System (ADS)

    Trabolsy, Zuhra Bashir Khalifa Al; Anouar, El Hassane; Zakaria, Nur Shahidatul Shida; Zulkeflee, Manar; Hasan, Mizaton Hazizul; Zin, Maisarah Mohd; Ahmad, Rohaya; Sultan, Sadia; Weber, Jean-Frédéric F.

    2014-02-01

    Fungal metabolite terrein isolated from Aspergillus terreus is endowed with diverse biological and antioxidant activities. To determine the stereochemistry of the isolated terrein, we combined spectroscopic methods (CD and NMR spectra) and theoretical calculations (DFT and TD-DFT methods). Stereochemistry effects on the antioxidant activity of isolated terrein were evaluated by calculating bond dissociation enthalpies (BDEs), ionization potentials (IPs) and spin density delocalization of terrein and isoterrein stereoisomers with B3P86/6-31+G (d, p) method in gas and polarizable continuum model. The results showed a good agreement between experimental data and theoretical calculations which confirmed the (+)-terrein stereochemistry of isolated metabolite. Theoretical calculations showed that the antioxidant activity is relatively influenced by isomeric geometry of the terrein (a variation of 2 kcal/mol between BDEs of terrein and isoterrein isomers), while chirality has no influence on the antioxidant activity [0.2 kcal/mol difference between BDEs of (+)- and (-)-terrein]. The low antioxidant activity of (+)-terrein with respect to trolox and ascorbic acid was explained by the positive free Gibbs energy of the hydrogen atom transfer (HAT) mechanism and high BDE values of the 2-OH active site.

  1. [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. PMID:20460865

  2. 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…

  3. Physical Activity at Daycare: Childcare Providers' Perspectives for Improvements

    ERIC Educational Resources Information Center

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

    2011-01-01

    In London, Ontario, approximately 45 percent of preschoolers are insufficiently active.With the large number of preschoolers who attend childcare (54%), and the low levels of physical activity among preschool-aged children, daycare centers may be an appropriate avenue to intervene. This study sought to collect childcare providers' suggestions for…

  4. 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…

  5. 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. PMID:25697582

  6. 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…

  7. 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…

  8. 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…

  9. Crystal structure and theoretical calculations of Julocrotine, a natural product with antileishmanial activity

    NASA Astrophysics Data System (ADS)

    Moreira, Rafael Y. O.; Brasil, Davi S. B.; Alves, Cláudio N.; Guilhon, Giselle M. S. P.; Santos, Lourivaldo S.; Arruda, Mara S. P.; Müller, Adolfo H.; Barbosa, Patrícia S.; Abreu, Alcicley S.; Silva, Edilene O.; Rumjanek, Victor M.; Souza, Jaime, Jr.; da Silva, Albérico B. F.; Santos, Regina H. De A.

    Julocrotine, N-(2,6-dioxo-1-phenethyl-piperidin-3-yl)-2-methyl-butyramide, is a potent antiproliferative agent against the promastigote and amastigote forms of Leishmania amazonensis (L.). In this work, the crystal structure of Julocrotine was solved by X-ray diffraction, and its geometrical parameters were compared with theoretical calculations at the B3LYP and HF level of theory. IR and NMR spectra also have been obtained and compared with theoretical calculations. IR absorptions calculated with the B3LYP level of theory employed together with the 6-311G+(d,p) basis set, are close to those observed experimentally. Theoretical NMR calculations show little deviation from experimental results. The results show that the theory is in accordance with the experimental data.0

  10. 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

  11. Molecular structure and nicotinic activity of arecoline. A gas electron diffraction study combined with theoretical calculations

    NASA Astrophysics Data System (ADS)

    Takeshima, Tsuguhide; Takeuchi, Hiroshi; Egawa, Toru; Konaka, Shigehiro

    2005-01-01

    The molecular structure of arecoline (methyl 1,2,5,6-tetrahydro-1-methylnicotinate, ? has been determined by gas electron diffraction. Diffraction patterns were taken at about 370 K. Structural constraints for the data analysis were obtained from MP2/6-31G** calculations. Vibrational mean amplitudes and shrinkage corrections were calculated from the force constants obtained from the gas-phase vibrational frequencies and the B3LYP/6-31G** calculations. The electron diffraction data were well reproduced by assuming the mixture of four conformers. The determined structural parameters ( rg (Å) and ∠ (°)) for the main conformer with 3 σ in parentheses are as follows: < rg(N-C ring)>=1.456(4); rg(N-C methyl)=1.451 (d.p.); rg(C dbnd6 C)=1.339(9); < rg(C-C)>=1.512(3); rg(O-C methyl)=1.434(5); rg(C(O)-O)=1.355 (d.p.); rg(C dbnd6 O)=1.209(4); the out-of-plane angle of the methyl group=50.3(23); ∠C ringN ringC ring=112.8(30); ∠N ringC ringC ring(H 2)=110.5(16); <∠C ringC ringC ring>=118.4(5); ∠C dbnd6 CC(O)=116.8(7); ∠CC dbnd6 O=127.6(9); ∠CC-O=109.8(8), where the angle brackets denote averaged values and d.p. denotes dependent parameters. Fixing the abundances of the minor conformers, Ax-s- cis and Ax-s- trans, at the theoretical values (13% in total), those of the Eq-s- cis and Eq-s- trans conformers were determined to be 46(16) and 41(16)%, respectively. Here Ax and Eq denote the axial and equatorial directions of the N-CH 3 bond and s- cis and s- trans show the orientation of the methoxycarbonyl group expressed by the configuration of the C dbnd6 O and C dbnd6 C bonds. The N⋯O carbonyl distances of the Eq-s- cis and Ax-s- cis conformers are 4.832(13) and 4.874(16) Å, respectively. They are close to the N⋯N distance of the most abundant conformer of nicotine, 4.885(6) Å, suggesting that the Eq-s- cis and Ax-s- cis conformers have nicotinic activity.

  12. 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…

  13. 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.

  14. Challenges and perspectives in the geological study of active faults.

    NASA Astrophysics Data System (ADS)

    Rizza, M.

    2011-12-01

    Identification of active faults is important for understanding regional seismicity and seismic hazard. A large part of the world's population lives in areas where destructive earthquakes or tsunamis were recorded in the past. Most of the difficulties in estimating seismic hazard and anticipating earthquakes are due to a lack of knowledge about the location of active faults and their seismic history. Even where active faults are known the characteristics of past earthquakes and the seismic cycle are uncertain and subject to discussion. Investigations carried out on active faults during the past decade, however, have provided new high-quality data and powerful tools to better understand crustal deformation and the recurrence of earthquakes. In morphotectonic studies, the ever-improving resolution of satellites images allows geologists to identify with more certainty the traces of active faults and even earthquake surface ruptures of the past. The advantage of satellite imagery for identifying neotectonic features is it gives access to large areas, sometimes difficult to reach in the field and provides synoptic views. Using the potential of high-resolution imagery and digital elevation models, geologists can produce detailed 3D reconstructions of fault morphology and geometry, including the kinematics of repeated slip. The development of new dating techniques, coupled with paleoseismology and quantitative geomorphology, now allows bracketing the occurrence of paleoearthquakes back to several thousand years, as well as analyzing long time sequences of events. Despite such wealth of new data, however, the work remaining to do is huge. Earthquake forecast (location, timing, magnitude) remains an unsolved problem for the earthquake community at large (seismologists, geodesists, paleoseismologists and modelers). The most important challenges in the next decade will be to increase the efficiency of neotectonic studies to create more complete active fault databases and

  15. 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

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. 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…

  1. 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.

  2. 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.

  3. 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.

  4. 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. PMID:24679519

  5. 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.

  6. Impacts of climate extremes on activity sectors stakeholders' perspective

    NASA Astrophysics Data System (ADS)

    Kundzewicz, Z. W.; Giannakopoulos, C.; Schwarb, M.; Stjernquist, I.; Schlyter, P.; Szwed, M.; Palutikof, J.

    2008-06-01

    Significant changes in the climatic system have been observed, which may be attributed to human-enhanced greenhouse effect. Even stronger changes are projected for the future, impacting in an increasing way on human activity sectors. The present contribution, prepared in the framework of the MICE (Modelling the Impact of Climate Extremes) Project of the European Union, reviews how climate change may impact on winter tourism in the Alpine region, intense precipitation and flood potential in central Europe, forest damage in Scandinavia and beach holidays in the Mediterranean coast. Impacts are likely to be serious and largely adverse. Due to a lack of adequate information and lack of broadly accepted and reliable mathematical models describing the impact of changes in climate extremes on these activity sectors, it has been found useful to use expert judgement based impact assessment. Accordingly, regional mini-workshops were organized serving as platforms for communication between scientists and stakeholders, vehicles for dissemination of the state-of-the-art of the scientific understanding and for learning stakeholders’ view on extreme events, their impacts and the preparedness system. Stakeholders had the opportunity to react to the scientific results and to reflect on their perception of the likely impacts of projected changes in extremes on relevant activity sectors and the potential to adapt and avert adverse consequences. The results reported in this paper present the stakeholders’ suggestions for essential information on different extreme event impacts and their needs from science.

  7. 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. PMID:17640514

  8. Parents' Perspectives of Early Childhood Special Education, Engagement in Everyday Learning Activities, and Kindergarten Performance of Children with Disabilities

    ERIC Educational Resources Information Center

    Epley, Pamela H.

    2013-01-01

    This study examined the relationship between parents' perspectives of early childhood special education (ECSE) and their engagement in everyday learning activities with kindergarten performance of children with disabilities in one Midwestern state. Findings show that although parents' perspective of ECSE and their engagement in everyday learning…

  9. Modulation of Brain Activity during Action Observation: Influence of Perspective, Transitivity and Meaningfulness

    PubMed Central

    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. PMID:21931832

  10. Sexual Activity and Heart Patients: A Contemporary Perspective.

    PubMed

    Stein, Ricardo; Sardinha, Aline; Araújo, Claudio Gil S

    2016-04-01

    Sexual activity (SA) encompasses several behaviors such as kissing (Ki), touching (T), oral (O) stimulation, masturbation (M), and vaginal/anal intercourse (I). The acronym KiTOMI is proposed here to represent these behaviors. SA, particularly coitus, is a major aspect of health-related quality of life and is often considered the most pleasant and rewarding exercise performed during an entire lifetime. Although several studies have been conducted on sexuality, relatively limited information is available regarding SA in patients with heart disease. Moreover, the level of evidence of this limited information is nearly always B or C. This article provides a comprehensive and updated review of the relevant literature and offers evidence and expert-based practical messages regarding SA in patients with heart disease. Considering the rationale for exercise prescription, SA is typically well tolerated by most clinically stable patients with heart disease. Even in more debilitated and sicker individuals, KiT activities would most likely be feasible and desirable. The absolute risk of major adverse cardiovascular events during SA is typically very low. Even lower death rates have been reported for specific groups, such as women in general, aerobically fit men, and asymptomatic young adults with congenital heart disease. Finally, we emphasize the relevance of sexual counselling for patients and their partners, including the proper use of medications to treat erectile dysfunction. Counselled patients will be reassured and adequately informed regarding how to gradually resume habitual SA after a major cardiac event or procedure, starting with KiT and progressively advancing to KiTOM until all KiTOMI activities are allowed. PMID:26690295

  11. 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. PMID:24188269

  12. Barriers to Participation in Physical Activity Among South Sudanese Children in South Australia: Parents' Perspectives.

    PubMed

    Mude, William; Mwanri, Lillian

    2016-01-01

    Physical inactivity is one of the determinants of childhood obesity. Although its facilitators are well documented for the general community, limited evidence exists informing newly arrived and emerging migrant communities in Australia. To explore parents' perspectives of barriers to participation in physical activity among South Sudanese children in South Australia. Qualitative, face-to-face interviews were conducted with parents. Data were transcribed, coded, and analyzed thematically using NVivo software. Multiple and complex barriers to physical activity participation were described. Enabling and supportive programs are needed to improve physical activity participation and health outcomes of new migrants. PMID:27536934

  13. 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. PMID:26324394

  14. 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…

  15. 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

  16. MHD activity in the ISX-B tokamak: experimental results and theoretical interpretation

    SciTech Connect

    Carreras, B.A.; Dunlap, J.L.; Bell, J.D.; Charlton, L.A.; Cooper, W.A.; Dory, R.A.; Hender, T.C.; Hicks, H.R.; Holmes, J.A.; Lynch, V.E.

    1982-01-01

    The observed spectrum of MHD fluctuations in the ISX-B tokamak is clearly dominated by the n=1 mode when the q=1 surface is in the plasma. This fact agrees well with theoretical predictions based on 3-D resistive MHD calculations. They show that the (m=1; n=1) mode is then the dominant instability. It drives other n=1 modes through toroidal coupling and n>1 modes through nonlinear couplings. These theoretically predicted mode structures have been compared in detail with the experimentally measured wave forms (using arrays of soft x-ray detectors). The agreement is excellent. More detailed comparisons between theory and experiment have required careful reconstructions of the ISX-B equilibria. The equilibria so constructed have permitted a precise evaluation of the ideal MHD stability properties of ISX-B. The present results indicate that the high ..beta.. ISX-B equilibria are marginally stable to finite eta ideal MHD modes. The resistive MHD calculations also show that at finite ..beta.. there are unstable resistive pressure driven modes.

  17. Health benefits of physical activity during pregnancy: an international perspective.

    PubMed

    Mudd, Lanay M; Owe, Katrine M; Mottola, Michelle F; Pivarnik, James M

    2013-02-01

    While early studies on the effects of leisure time physical activity (LTPA) during pregnancy were concerned about possible harm to the mother or fetus, these fears have not been substantiated. Instead, a growing body of literature has documented several health benefits related to pregnancy LTPA. The purpose of this article was to synthesize evidence from epidemiological studies conducted in the United States, Canada, and Scandinavia on the benefits of LTPA and exercise during pregnancy with regard to maternal health, pregnancy outcomes, and child health. We focused on studies evaluating relations between pregnancy LTPA and gestational diabetes, hypertensive disorders, excessive gestational weight gain, birth weight, timing of delivery, and child body composition. The bulk of evidence supports beneficial effects of pregnancy LTPA on each outcome; however, most previous studies have been observational and used self-reported LTPA at only one or two time points in pregnancy. Limitations of the current knowledge base and suggestions for future research on the health benefits of LTPA during pregnancy are provided. PMID:22895379

  18. European activities in exobiology in earth orbit: results and perspectives

    NASA Astrophysics Data System (ADS)

    Horneck, G.

    1999-01-01

    A large portion of European activities in Earth orbit have concentrated on studies of the responses of resistant microbes to the harsh environment of space with the aim of providing experimental evidence testing the hypothesis that interplanetary transfer of life is possible. Various types of microorganisms, such as bacterial or fungal spores, as well as viruses and biomolecules, such as DNA, amino acids and liposomes, have been exposed to selected and combined space conditions outside the Earth's magnetic field (Apollo 16) or in low Earth orbit (Spacelab 1, Spacelab D2, ERA on EURECA, LDEF, BIOPAN on FOTON). Space parameters, such as high vacuum, intense solar ultraviolet radiation, different components of the cosmic radiation field and temperature extremes affected the genetic stability of the organisms in space, leading to increased mutation rates, DNA damage and inactivation. Extraterrestrial solar UV radiation was the most lethal factor. If shielded against the influx of solar UV, spores of Bacillus subtilis survived for more than 5 years in space. Future research will be directed towards long-term studies of microbes in artificial meteorites, as well as of microbial communities from special ecological niches, such as endolithic and endoevaporitic ecosystems. For these studies, the European Space Agency will provide the facility EXPOSE to be accommodated on the External Platform of the International Space Station during the Early Utilization Phase.

  19. [Professional activity of "competent physician": actual troubles and future perspectives].

    PubMed

    Ramistella, E; Maviglia, A

    2010-01-01

    In recent years, Health has experienced a great transformation, due to the latest technological breakthroughs, the discovery of new drugs and changing social and economic conditions of our country. The professional activity of the "competent physician", even, from the definition of art. 33 of DPR 303/56, result in today's complex set of procedural formalities that make your role as a great professional and social responsibility. However, there are still areas of uncertainty in the law and different interpretations that make it difficult to work. The competent physicians faced with a series of problems that hinder the development of their work, instead, should be free from interference in order to always get the expected results in preserving the worker's health. After a brief discussion of the main weaknesses found, are made some concrete proposals to ensure that the physician in the foreseeable future is increasingly a qualified professional capable of responding adequately to the needs arising from modern scientific evidence and the expectations of workers and the whole society. PMID:21086700

  20. Dike propagation in active volcanoes: importance, evidence, models and perspectives

    NASA Astrophysics Data System (ADS)

    Acocella, V.

    2011-12-01

    Most eruptions are fed by dikes; therefore, better knowledge of dike propagation is crucial to improve our understanding of how magma is transferred and extruded at volcanoes. Dike pattern data from a few tens of active volcanic edifices show how dike propagation in a volcano is not a random process; rather, it depends from the following factors (listed in order of importance): the presence of relief, the shape of the edifice, the proximity to the surface, and regional tectonic control. Relief enhances the development of radial dikes, which may also cluster following volcano elongation or regional patterns. Dikes approaching the surface of volcanic edifices, regardless of their initial orientation, reorient to become radial (parallel to the maximum gravitational stress); in presence of scarps, dikes reorient subparallel to the scarp (perpendicular to the minimum gravitational stress). These relationships have been also observed or inferred during eruptions at Etna, Stromboli, Vesuvio (Italy), Erta Ale (Afar) and Faial (Azores). While numerical modelling of dike propagation remains challenging, analogue models of dike emplacement have been performed over a few decades, also supporting part of the above-described evidence. Analogue models have been mostly conducted injecting air or water within gelatine and, recently, injecting vegetable oil within sand. More sophisticated analogue modelling is foreseen for the future, using a more appropriate scaling, a larger sensitivity and providing a more quantitative approach in capturing relationships. More in general, future research on dikes should be devoted towards identifying dike propagation paths, dike arrest mechanisms, and likely locations of vent formation at specific volcanoes, to better aid hazards assessment.

  1. Theoretical modeling of photocatalytic active species on illuminated TiO 2

    NASA Astrophysics Data System (ADS)

    Belelli, Patricia G.; Ferullo, Ricardo M.; Branda, María M.; Castellani, Norberto J.

    2007-10-01

    A theoretical study of the H 2O and O 2 adsorption on an illuminated TiO 2 anatase surface is presented. The electronic structure and the spin distribution were examined by employing the DFT formalism and the BHandHLYP functional. The adsorbates geometries were fully optimized, including the cluster relaxation. Our results show the dissociative adsorption of the H 2O molecule on the photoactivated TiO 2 (0 0 1) surface. This reaction produces one hydroxyl group with radical character (OH rad ) and an unpaired electron localized in the 5c-Ti atom. In case of the O 2 molecule, the non-dissociative chemisorption was obtained. This molecule shows one unpaired electron and a negative charge. In these sense, the adsorbed O 2 acts as a superoxide species (O 2rad -).

  2. Activation and Reactivity of a Bispidine Analogue of Cisplatin: A Theoretical Investigation.

    PubMed

    Graziani, Valentina; Coletti, Cecilia; Marrone, Alessandro; Re, Nazzareno

    2016-07-14

    The reactivity of a bispidine, 3,7-diazabicyclo[3.3.1]nonane, analogue of cisplatin, a new anticancer drug with promising properties, is theoretically investigated to clarify the in vitro reactivity and in vivo mechanism of action of this compound. Thermodynamics and kinetics of the first and second aquation steps and of the reaction of the generated mono- and diaqua species with guanine, the main target of the platinum based antitumor compounds, have been studied. In agreement with the experimental evidence, the bispidine analogue is significantly less reactive than cisplatin toward aquation but the formed aquaspecies show a good reactivity with guanine, consistently with the promising anticancer properties of these new compounds. PMID:27070849

  3. Capturing Unique Dimensions of Youth Organized Activity Involvement: Theoretical and Methodological Considerations

    ERIC Educational Resources Information Center

    Bohnert, Amy; Fredricks, Jennifer; Randall, Edin

    2010-01-01

    Despite increased focus on the effects of organized activities on youth development, there is currently no consensus about the best way to assess various dimensions of involvement. This article explores the complexities of assessing involvement and focuses specifically on the following organized activity dimensions: (a) breadth, (b) intensity, (c)…

  4. 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…

  5. Activity Theory in Information Systems Research and Practice: Theoretical Underpinnings for an Information Systems Development Model

    ERIC Educational Resources Information Center

    Mursu, Anja; Luukkonen, Irmeli; Toivanen, Marika; Korpela, Mikko

    2007-01-01

    Introduction: The purpose of information systems is to facilitate work activities: here we consider how Activity Theory can be applied in information systems development. Method. The requirements for an analytical model for emancipatory, work-oriented information systems research and practice are specified. Previous research work in Activity…

  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. PMID:23240823

  7. Physical, Psychological and Emotional Benefits of Green Physical Activity: An Ecological Dynamics Perspective.

    PubMed

    Yeh, Hsiao-Pu; Stone, Joseph Antony; Churchill, Sarah May; Wheat, Jonathan Stephen; Brymer, Eric; Davids, Keith

    2016-07-01

    Increasing evidence supports the multiple benefits to physical, psychological and emotional wellbeing of green physical activity, a topic of increasing interest in the past decade. Research has revealed a synergistic benefit of green physical activity, which includes all aspects of exercise and physical activity in the presence of nature. Our theoretical analysis suggests there are three distinct levels of engagement in green physical activity, with each level reported to have a positive effect on human behaviours. However, the extent to which each level of green physical activity benefits health and wellbeing is assumed to differ, requiring confirmation in future research. This elucidation of understanding is needed because previous literature has tended to focus on recording empirical evidence rather than developing a sound theoretical framework to understand green physical activity effects. Here we propose an ecological dynamics rationale to explain how and why green physical activity might influence health and wellbeing of different population groups. This framework suggests a number of unexplored, interacting constraints related to types of environment and population groups, which shape reported levels of benefit of green physical activity. Further analysis is needed to clarify the explicit relationship between green physical activity and health and wellbeing, including levels of engagement, types of environmental constraints, levels of physical activity, adventure effects, skill effects and sampling of different populations. PMID:26330207

  8. 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

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

    PubMed

    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

  10. Part-Time Work and Hurried Adolescence: The Links between Work Intensity, Social Activities, Health Behaviors, and Substance Use.

    ERIC Educational Resources Information Center

    Safron, Deborah J.; Schulenberg, John E.; Bachman Jerald G.

    2002-01-01

    This study examines adolescents' part-time work intensity and its relation to participation in various activities as well as substance use. Two theoretical perspectives are considered: the "time trade-off perspective"; and "the precocious development perspective." Results provide evidence for a combination of both perspectives. (Author)

  11. Electronic structure of some thymol derivatives correlated with the radical scavenging activity: theoretical study.

    PubMed

    Javan, Ashkan Jebelli; Javan, Marjan Jebeli

    2014-12-15

    Molecules acting as antioxidants capable of scavenging reactive oxygen species (ROS) are of upmost importance in the living cell. Thymol derivatives exhibit various antioxidant activities and potential health benefits. Exploration of structure-radical scavenging activity (SAR) was approached with a wide range of thymol derivatives. To accomplish this task, the DPPH experimental assay along with quantum-chemical calculations were also employed for these compounds. By comparing the structural properties of the derivatives of interest, their antioxidant activity was explained by the formation of an intramolecular hydrogen bond and the presence of unsaturated double bond (-CHCH substituent) in their radical spices. Moreover, the delocalization of odd electrons in these radicals has been investigated by natural bond orbital analysis and interpretation of spin density maps. Reactivity order of the compound towards the ROS: HO, HOO, and O2(-) was found to be as HO>HOO > O2(-). PMID:25038698

  12. 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

  13. New models for carrying out cyclic neutron activation. Discussion of the theoretical response

    NASA Astrophysics Data System (ADS)

    Castro-García, M. P.; Rey-Ronco, M. A.; Alonso-Sánchez, T.

    2014-11-01

    This paper studies two specific procedures for analyzing mining samples through a neutron activation technique called DGNAA (Delayed Gamma Neutron Activation Analysis). This particular study is part of a broader line of research, whose overall objective is to find the optimal procedure for analyzing the fluorite content of samples taken from different parts of a fluorite concentration plant, using the DGNAA method [1-2]. The mining sample is fluorspar, which contains other minerals in addition to fluorite, such as silica, barite, iron oxides and silicates. The main contribution of the article is the development of a new method for determining the fluorite content in minerals and the increase of sensitivity in respect to the symmetrical method and single-cycle activation.

  14. Detection of abnormal cardiac activity using principal component analysis--a theoretical study.

    PubMed

    Greisas, Ariel; Zafrir, Zohar; Zlochiver, Sharon

    2015-01-01

    Electrogram-guided ablation has been recently developed for allowing better detection and localization of abnormal atrial activity that may be the source of arrhythmogeneity. Nevertheless, no clear indication for the benefit of using electrograms guided ablation over empirical ablation was established thus far, and there is a clear need of improving the localization of cardiac arrhythmogenic targets for ablation. In this paper, we propose a new approach for detection and localization of irregular cardiac activity during ablation procedures that is based on dimension reduction algorithms and principal component analysis (PCA). Using an 8×8 electrode array, our method produces manifolds that allow easy visualization and detection of possible arrhythmogenic ablation targets characterized by irregular conduction. We employ mathematical modeling and computer simulations to demonstrate the feasibility of the new approach for two well established arrhythmogenic sources for irregular conduction--spiral waves and patchy fibrosis. Our results show that the PCA method can differentiate between focal ectopic activity and spiral wave activity, as these two types of activity produce substantially different manifold shapes. Moreover, the technique allows the detection of spiral wave cores and their general meandering and drifting pattern. Fibrotic patches larger than 2 mm(2) could also be visualized using the PCA method, both for quiescent atrial tissue and for tissue exhibiting spiral wave activity. We envision that this method, contingent to further numerical and experimental validation studies in more complex, realistic geometrical configurations and with clinical data, can improve existing atrial ablation mapping capabilities, thus increasing success rates and optimizing arrhythmia management. PMID:25073163

  15. Observation of EHO in NSTX and theoretical study of its active control using HHFW antenna

    NASA Astrophysics Data System (ADS)

    Park, J.-K.; Goldston, R. J.; Crocker, N. A.; Fredrickson, E. D.; Bell, M. G.; Maingi, R.; Tritz, K.; Jaworski, M. A.; Kubota, S.; Kelly, F.; Gerhardt, S. P.; Kaye, S. M.; Menard, J. E.; Ono, M.

    2014-04-01

    Two important topics for tokamak edge-localized modes (ELM) control, based on 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 (EHO) in NSTX (with lower frequency than EHOs in DIII-D and elsewhere), and theoretical study of its external drive using the high-harmonic fast wave (HHFW) antenna as a 3D field coil. EHOs were observed particularly clearly in NSTX ELM-free operation with very low n core modes. A number of diagnostics have confirmed n = 4-6 edge-localized and coherent oscillations in the 2-8 kHz frequency range. These oscillations seem to have a favoured operational window in rotational shear, similar to EHOs in DIII-D quiescent H modes. However, in NSTX, they are not observed to provide significant particle or impurity transport, 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, ideal perturbed equilibrium code calculations show that the optimized configuration with only 1 kAt current can produce comparable or larger displacements than the observed internal modes. Thus it may be possible to use externally driven EHOs to relax the edge pressure gradient and control ELMs in NSTX-U and future devices. Fine and external control over the edge pressure gradient would be a very valuable tool for tokamak control.

  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. 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.

  18. 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…

  19. 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…

  20. Are intramolecular frustrated Lewis pairs also intramolecular catalysts? A theoretical study on H2 activation.

    PubMed

    Zeonjuk, Lei Liu; St Petkov, Petko; Heine, Thomas; Röschenthaler, Gerd-Volker; Eicher, Johannes; Vankova, Nina

    2015-04-28

    We investigate computationally a series of intramolecular frustrated Lewis pairs (FLPs), with the general formula Mes2PCHRCH2B(C6F5)2, that are known from the literature to either activate molecular hydrogen (FLPs with R = H (1) or Me (4)), or remain inert (FLPs with R = Ph (2) or SiMe3 (3)). The prototypical system Mes2PCH2CH2B(C6F5)2 (1) has been described in the literature (Grimme et al., Angew. Chem., Int. Ed., 2010; Rokob et al., J. Am. Chem. Soc., 2013) as an intramolecular reactant that triggers the reaction with H2 in a bimolecular concerted fashion. In the current study, we show that the concept of intramolecular H2 activation by linked FLPs is not able to explain the inertness of the derivative compounds 2 and 3 towards H2. To cope with this, we propose an alternative intermolecular mechanism for the investigated reaction, assuming stacking of two open-chain FLP conformers, and formation of a dimeric reactant with two Lewis acid–base domains, that can split up to two hydrogen molecules. Using quantum-chemical methods, we compute the reaction profiles describing these alternative mechanisms, and compare the derived predictions with earlier reported experimental results. We show that only the concept of intermolecular H2 activation could explain both the activity of the FLPs having small substituents in the bridging molecular region, and the inertness of the FLPs with a bulkier substitution, in a consistent way. Importantly, the intermolecular H2 activation driven by intramolecular FLPs indicates the key role of steric factors and noncovalent interactions for the design of metal-free systems that can efficiently split H2, and possibly serve as metal-free hydrogenation catalysts. PMID:25812167

  1. "I Could Do with a Pair of Wings": Perspectives on Physical Activity, Bodies and Health from Young Australian Children

    ERIC Educational Resources Information Center

    Macdonald, Doune; Rodger, Sylvia; Abbott, Rebecca; Ziviani, Jenny; Jones, Judy

    2005-01-01

    There is little research that reports children's perspectives on physical activity, bodies and health. This paper, drawn from a larger multi-method study on physical activity in the lives of seven- and eight-year-old Australian children, attempts to "give a voice" to 13 children's views. Interviews focused on children's activity preferences and…

  2. Correlation of antioxidant activities with theoretical studies for new hydrazone compounds bearing a 3,4,5-trimethoxy benzyl moiety.

    PubMed

    Kareem, Huda S; Ariffin, Azhar; Nordin, Nurdiana; Heidelberg, Thorsten; Abdul-Aziz, Azlina; Kong, Kin Weng; Yehye, Wageeh A

    2015-10-20

    A new series of antioxidants, namely imines bearing the well-known free radical scavenger group 3,4,5-trimethoxybenzyloxy, was designed and synthesized. Theoretical calculations based on density functional theory (DFT) were performed to understand the antioxidant activities. Experimental studies evaluating the antioxidant activities of the compounds using DPPH and FRAP assays verified the predictions obtained by DMOL3 based on DFT.1. The DPPH radical scavenging activities depended on the substitution pattern of the aromatic aldehyde, with both the substitution type and position showing significant effects. Compounds 7b, 7c and 7d, which contain a phenolic hydroxyl group at the para position to the imine as well as, additional electron donating groups at the ortho-position to this hydroxyl group, exhibited IC₅₀ values of 62, 75 and 106 μg/mL, respectively, and potent antioxidant activities against DPPH, which were better than that of the reference compound BHT. With the exception of compounds 7a and 7h with a phenolic hydroxyl group at the ortho position, all of the investigated compounds exhibited ferric reducing activities above 1000 μM. Correlation analysis between the two antioxidant assays revealed moderate positive correlation (r = 0.59), indicating differing antioxidant activities based on the reaction mechanism. Therefore, imines bearing a 3,4,5-trimethoxybenzyloxy group can be proposed as potential antioxidants for tackling oxidative stress. PMID:26402727

  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. PMID:25803685

  4. Approach to theoretical estimation of the activation energy of particle aggregation taking ionic nonclassic polarization into account

    NASA Astrophysics Data System (ADS)

    Li, Qinyi; Tang, Ying; He, Xinhua; Li, Hang

    2015-10-01

    The activation energy of particle aggregation in suspensions is a very important kinetic parameter in a wide range of science and engineering applications. At present, however, there is no theory that can theoretically predict the activation energy. Because the activation energy is often less than 10 kT (where k is the Boltzmann constant and T is the temperature), it is difficult to experimentally measure. In this study, a theory for calculating the activation energy is established. Experimental measurements of the activation energy of montmorillonite aggregation were performed with different electrolyte and particle concentrations using the dynamic light scattering (DLS) technique. The validity of the theory was verified by the experiments. This study confirmed that both the method for activation energy measurements by DLS and the theory for its calculation can be applied to suspensions of polydisperse nonspherical particles. The average kinetic energy at the moment of particle collision in the aggregation process was found to be 0.2 kT, which is less than the instantaneous kinetic energy of a Brownian particle (0.5 kT) because of the viscous resistance of the water medium. This study also shows that adsorbed Na+ is strongly polarized in the electric field near the particle surface, and the polarization increases the effective charge of Na+ from +1 to +1.18.

  5. 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

  6. Theoretical study on the adsorption of phenol on activated carbon using density functional theory.

    PubMed

    Cam, Le Minh; Van Khu, Le; Ha, Nguyen Ngoc

    2013-10-01

    Density functional theory (DFT) calculations performed at the PBE/DZP level using the DFT-D2 method were utilized to investigate the adsorption of phenol on pristine activated carbon (AC) and on activated carbon functionalized with OH, CHO, or COOH groups. Over the pristine AC, the phenol molecule undergoes weak physical adsorption due to van der Waals interactions between the aromatic part of the phenol and the basal planes of the AC. Among the three functional groups used to functionalize the AC, the carboxylic group was found to interact most strongly with the hydroxyl group of phenol. These results suggest that functionalized AC-COOH has great potential for use in environmental applications as an adsorbent of phenol molecules in aqueous phases. PMID:23918222

  7. 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.

  8. A theoretical model for the magnetic helicity of solar active regions

    NASA Astrophysics Data System (ADS)

    Choudhuri, A. R.; Chatterjee, P.; Petrovay, K.; Nandy, D.

    Active regions on the solar surface are known to possess magnetic helicity which is predominantly negative in the northern hemisphere and positive in the southern hemisphere Choudhuri 2003 Sol Phys 123 217 proposed that the magnetic helicity arises due to the wrapping up of the poloidal field of the convection zone around rising flux tubes which form active regions Choudhuri Chatterjee and Nandy 2004 ApJ 615 L57 used this idea to calculate magnetic helicity from their solar dynamo model and found broad agreements with observational data Chatterjee Choudhuri and Petrovay 2006 A A in press have studied the penetration of the wrapped poloidal field into the rising flux tube and concluded that more detailed observational data will throw light on the physical conditions of flux tubes just before their emergence to the photosphere

  9. 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.

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

    PubMed

    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

  11. A theoretical model for the magnetic helicity of solar active regions

    NASA Astrophysics Data System (ADS)

    Chatterjee, Piyali; Choudhuri, Arnab Rai; Petrovay, Kristof; Nandy, Dibyendu

    Active regions on the solar surface are known to possess magnetic helicity, which is predominantly negative in the northern hemisphere and positive in the southern hemisphere. Choudhuri et al. [Choudhuri, A.R. On the connection between mean field dynamo theory and flux tubes. Solar Phys. 215, 31 55, 2003] proposed that the magnetic helicity arises due to the wrapping up of the poloidal field of the convection zone around rising flux tubes which form active regions. Choudhuri [Choudhuri, A.R., Chatterjee, P., Nandy, D. Helicity of solar active regions from a dynamo model. ApJ 615, L57 L60, 2004] used this idea to calculate magnetic helicity from their solar dynamo model. Apart from getting broad agreements with observational data, they also predict that the hemispheric helicity rule may be violated at the beginning of a solar cycle. Chatterjee et al. [Chatterjee, P., Choudhuri, A.R., Petrovay, K. Development of twist in an emerging magnetic flux tube by poloidal field accretion. A&A 449, 781 789, 2006] study the penetration of the wrapped poloidal field into the rising flux tube due to turbulent diffusion using a simple 1-d model. They find that the extent of penetration of the wrapped field will depend on how weak the magnetic field inside the rising flux tube becomes before its emergence. They conclude that more detailed observational data will throw light on the physical conditions of flux tubes just before their emergence to the photosphere.

  12. 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

  13. 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

  14. Theoretical analysis of non-radiative multiphonon recombination activity of intrinsic defects in CdTe

    NASA Astrophysics Data System (ADS)

    Krasikov, D. N.; Scherbinin, A. V.; Knizhnik, A. A.; Vasiliev, A. N.; Potapkin, B. V.; Sommerer, T. J.

    2016-02-01

    We present an analysis of recombination activity of intrinsic defects (VCd, TeCd, VTe, and Tei) in CdTe based on the multiphonon single-mode carrier-capture model, with vibronic parameters obtained using hybrid density functional theory. This analysis allows us to determine the defects and the corresponding electronic processes that have high trapping rates for electrons, for holes, or for both. The latter, being potentially the most active recombination centers, decreases the carrier lifetime in the absorber layer of a CdTe solar cell. Taking into account the relatively high calculated capture cross-sections of the TeCd antisite defect (σ = 8.7× 10-15 cm2 for electron capture on TeCd+2 defect, σ = 6.8 × 10-14 cm2 for hole capture on TeCd+1 defect at room temperature) and its deep trapping level (0.41 eV for +2/+1 level), we conclude that this defect is the most active recombination center among the intrinsic defects in p-type CdTe. Other processes that do not lead to effective recombination are: (i) fast hole capture on Tei+1 defect (σ = 1.1 × 10-13 cm-2), (ii) electron capture on TeCd+1 defect (σ = 2.9 × 10-15 cm-2), (iii) somewhat slower hole capture on TeCd0 defect (σ = 9.4 × 10-20 cm-2), (iv) hole capture on VCd-1 defect (σ = 7 × 10-19 cm2), and (v) electron capture on Tei+1 defect (σ = 4.4 × 10-19 cm-2). The cross-sections are found to be negligibly small for the remaining capture processes.

  15. Theoretical study of mode evolution in active long tapered multimode fiber.

    PubMed

    Shi, Chen; Wang, Xiaolin; Zhou, Pu; Xu, Xiaojun; Lu, Qisheng

    2016-08-22

    A concise and effective model based on coupled mode theory to describe mode evolution in long tapered active fiber is presented in this manuscript. The mode coupling due to variation of core radius and slight perturbation have been analyzed and local gain with transverse spatial hole burning (TSHB) effect, loss and curvature have been taken into consideration in our model. On the base of this model, the mode evolution behaviors under different factors have been numerically investigated. Our model and results can provide instructive suggestions when designing long tapered fiber based laser and amplifiers. PMID:27557225

  16. 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

  17. Proficient synthesis of biologically active pregnane derivatives and its glycoside - Experimental and theoretical approach

    NASA Astrophysics Data System (ADS)

    Sethi, Arun; Bhatia, Akriti; Maurya, Atul; Panday, Anil; Bhatia, Gitika; Shrivastava, Atul; Singh, Ranvijay Pratap; Prakash, Rohit

    2013-11-01

    Synthesis of a number of pregnane derivatives including the glycoside has been described in detail. These compounds were synthesized by reaction of 3β-acetoxy-5, 16-pregnadiene-20-one, derived from diosgenin and then treating it with different nucleophilic reagents. The structures of these newly synthesized compounds were established on the basis of their physical, chemical and spectral data. The molecular geometry of compounds were calculated in ground state by density functional theory method (DFT/B3LYP) using 6-31G (d,p) basis set. 1H NMR chemical shifts were also studied using gauge-including atomic orbital (GIAO) approach, which were found in good agreement with the experimental values. The study of electronic properties such as UV-Vis spectral analysis, HOMO and LUMO energy calculations were performed with time dependent DFT (TD-DFT). Global and local reactivity descriptors were calculated to study the reactive sites within the molecules. These compounds were also evaluated for their anti-dyslipidemic (Triton model) and in vitro anti-oxidant activities. Out of these, compound 9 showed potent anti-dyslipidemic and anti-oxidant activity.

  18. Effects of ultrasound frequency and acoustic amplitude on the size of sonochemically active bubbles - Theoretical study.

    PubMed

    Merouani, Slimane; Hamdaoui, Oualid; Rezgui, Yacine; Guemini, Miloud

    2013-05-01

    Numerical simulation of chemical reactions inside an isolated spherical bubble of oxygen has been performed for various ambient bubble radii at different frequencies and acoustic amplitudes to study the effects of these two parameters on the range of ambient radius for an active bubble in sonochemical reactions. The employed model combines the dynamic of bubble collapse with the chemical kinetics of single cavitation bubble. Results from this model were compared with some experimental results presented in the literature and good apparent trends between them were observed. The numerical calculations of this study showed that there always exists an optimal ambient bubble radius at which the production of oxidizing species at the end of the bubble collapse attained their upper limit. It was shown that the range of ambient radius for an active bubble increased with increasing acoustic amplitude and decreased with increasing ultrasound frequency. The optimal ambient radius decreased with increasing frequency. Analysis of curves showing optimal ambient radius versus acoustic amplitude for different ultrasonic frequencies indicated that for 200 and 300kHz, the optimal ambient radius increased linearly with increasing acoustic amplitude up to 3atm. However, slight minima of optimal radius were observed for the curves obtained at 500 and 1000kHz. PMID:23187064

  19. 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.

  20. 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.

  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

    2016-01-01

    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, (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. PMID:26218917

  2. Theoretical modeling of planet-induced stellar activity using A.I.K.E.F. simulations

    NASA Astrophysics Data System (ADS)

    Riousset, J. A.; Motschmann, U.; Reiners, A.; Marvin, C.

    2015-12-01

    Plasma flows and turbulences in stellar atmospheres and chromospheres can be disturbed by the presence of a planet in close orbit around the star. Such disturbances can be generated through tidal interactions between the two bodies, or through direct magnetic interaction between the magnetic fields of the star and the planet. The presence of an outer disturber and its influence on the generation of stellar activity, together with the knowledge about stars with no close planets, provide a unique laboratory for the investigation of plasma turbulence in stellar atmospheres. In this work we develop an integrated model covering the star and the planet as an interacting system where gravitational and electromagnetic forces are implemented self-consistently. The model is based on A.I.K.E.F. hybrid code for simulating stellar wind interaction with astronomical bodies. Compared to previous studies, the solar wind is no longer modeled as inflow/outflow boundary conditions, but created instead by a second body representing a star inside the simulation domain. The incorporation of the star is carried out based on Parker (1952) model for slow rotating stars with moderate stellar magnetic fields or on the sophisticated stellar wind model of Weber and Davis (1967) for fast rotators with strong stellar magnetic fields. Such an approach is not without scaling constraints, which will be discussed in this paper. Here, we present the first results for a configuration where the planet is within the star's Alfven radius, i.e., where the stellar wind flow velocity is subcritical. In this case, the resulting current system is extended and may even propagate against the inflowing stellar wind with possible consequences for the stellar activity.

  3. 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

  4. 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

  5. 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. PMID:18834087

  6. 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.

  7. 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.

  8. 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.

  9. Theoretical Modelling and Facile Synthesis of a Highly Active Boron-Doped Palladium Catalyst for the Oxygen Reduction Reaction.

    PubMed

    Vo Doan, Tat Thang; Wang, Jingbo; Poon, Kee Chun; Tan, Desmond C L; Khezri, Bahareh; Webster, Richard D; Su, Haibin; Sato, Hirotaka

    2016-06-01

    A highly active alternative to Pt electrocatalysts for the oxygen reduction reaction (ORR), which is the cathode-electrode reaction of fuel cells, is sought for higher fuel-cell performance. Our theoretical modelling reveals that B-doped Pd (Pd-B) weakens the absorption of ORR intermediates with nearly optimal binding energy by lowering the barrier associated with O2 dissociation, suggesting Pd-B should be highly active for ORR. In fact, Pd-B, facile synthesized by an electroless deposition process, exhibits 2.2 times and 8.8 times higher specific activity and 14 times and 35 times less costly than commercial pure Pd and Pt catalysts, respectively. Another computational result is that the surface core level of Pd is negatively shifted by B doping, as confirmed by XPS, and implies that filling the density of states related to the anti-bonding of oxygen to Pd surfaces with excess electrons from B doping, weakens the O bonding to Pd and boosts the catalytic activity. PMID:27086729

  10. Hypothermic activity of acetaminophen; involvement of GABAA receptor, theoretical and experimental studies

    PubMed Central

    Ahangar, Nematollah; Esam, Zohreh; Bekhradnia, Ahmadreza; Ebrahimzadeh, Mohammad Ali

    2016-01-01

    Objective(s): The mechanism of hypothermia action of acetaminophen (APAP) remains unclear even 125 years after its synthesis. Acetaminophen produces hypothermia. The mechanism of this reduction in core body temperature is not clear but evidence shows that it is not dependent on opioid and cannabinoid receptors. Because of strong documents about the roles of GABA and benzodiazepine receptors in hypothemic activity of some drugs such as diazepam, we determined if these receptors also contributes to the hypothermic effect of APAP. Materials and Methods: Diazepam (5 mg/kg, IP) was used for induction of hypothermia. Flumazenil (10 mg/kg, IP) or picrotoxin (2 mg/kg, IP) used for reversal of this effect. Rats injected with APAP (100, 200 or 300 mg/kg, IP). Baseline temperature measurements were taken with a digital thermometer via rectum. To evaluate the structural correlation between APAP and benzodiazepine receptor ligands, numerous models are selected and studied at HF/6-31G* level of theory. Relative energies, enthalpies and Gibbs free energies were calculated for all selected drugs. Results Diazepam induced hypothermia was reversed by flumazenil or picrotoxin. Rats injected with APAP displayed dose- and time-related hypothermia. For combined administration, the hypothermic effect of APAP (200 mg/kg) was strongly reduced by pretreatment with picrotoxin or flumazenil P<0.0001and P<0.01, respectively. Selective structural data, bond length, dihedral angles, and related distance in pharmacophore of APAP and BZDR models were the same. Some significant structural analogues were obtained between these drugs. Conclusion: Results suggest hypothermic action of acetaminophen may be mediate by its effect at GABAA benzodiazepine receptor. PMID:27403252

  11. 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

  12. 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,…

  13. 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. PMID:24983923

  14. 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.

  15. Theoretical Investigations and Density Functional Theory Based Quantitative Structure–Activity Relationships Model for Novel Cytotoxic Platinum(IV) Complexes

    PubMed Central

    2012-01-01

    Octahedral platinum(IV) complexes are promising candidates in the fight against cancer. In order to rationalize the further development of this class of compounds, detailed studies on their mechanisms of action, toxicity, and resistance must be provided and structure–activity relationships must be drawn. Herein, we report on theoretical and QSAR investigations of a series of 53 novel bis-, tris-, and tetrakis(carboxylato)platinum(IV) complexes, synthesized and tested for cytotoxicity in our laboratories. The hybrid DFT functional wb97x was used for optimization of the structure geometry and calculation of the descriptors. Reliable and robust QSAR models with good explanatory and predictive properties were obtained for both the cisplatin sensitive cell line CH1 and the intrinsically cisplatin resistant cell line SW480, with a set of four descriptors. PMID:23214999

  16. 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.

  17. 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

  18. 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

  19. Dutch Primary Schoolchildren's Perspectives of Activity-Friendly School Playgrounds: A Participatory Study.

    PubMed

    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

  20. 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

  1. 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. PMID:24692183

  2. 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

  3. Low-Income, Urban Children's Perspectives on Physical Activity: A Photovoice Project.

    PubMed

    Heidelberger, Lindsay; Smith, Chery

    2016-06-01

    Objectives The purpose of this research was to have ethnically diverse, 9- to 13-year-olds who live in urban, low-income households use Photovoice to represent their physical activity practices and their perception of their physical activity environment. Methods Photovoice methodology was used to allow children to capture their physical activity habits and environment through photographs and interviews. The Social Cognitive Theory was used as the theoretical framework. Heights and weights were taken for all children and BMI was calculated. Photographs were analyzed by recording the content of usable photos in SPSS software. Qualitative analysis of the interview transcripts used the open coding method. Results Participants were 24 children (15 male, 9 female) living in inner city, low-income households. On average, children were 10.9 years old and the mean BMI-for-age percentile was 72 %. Children took a total of 377 pictures and 339 of these were usable. Three themes were identified across interviews and photographs, (a) types of activity, (b) social environment, and (c) physical environment where activity took place. Conclusions for Practice This study provides insight into low-income, urban children's physical activity habits and environment using a novel approach. Potential ways to increase moderate to high intensity activity among this population are to involve church-based organizations, create more safe places to play by increasing green space in urban areas, and to provide financial support for after-school programs and community centers. PMID:26694042

  4. “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

  5. 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.

  6. 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…

  7. MSW Students' Perspectives on Social Work Goals and Social Activism before and after Completing Graduate Education

    ERIC Educational Resources Information Center

    Mizrahi, Terry; Dodd, Sarah-Jane

    2013-01-01

    This article analyzes perspectives on the goals of the social work profession and social activism of a cohort of MSW students before and after attending their graduate program. This study provides insights into the question about whether and how preexisting values, experiences, and background characteristics affect beginning and ending…

  8. 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).…

  9. 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…

  10. 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…

  11. One pot synthesis of biologically active pregnane derivatives, their single crystal structures, spectroscopic characterization and theoretical calculations

    NASA Astrophysics Data System (ADS)

    Sethi, Arun; Bhatia, Akriti; Bhatia, Gitika; Shrivastava, Atul; Prakash, Rohit

    2013-11-01

    One pot allylic oxidation of 3β-acetoxypregna-5,16-diene-20-one (2) and nucleophilic addition at C-16 position of 3β-hydroxypregna-5,16-diene-20-one (3) yielded 3β-acetoxypregna-5,16-diene-7,20-dione (4) and 3β-hydroxy-16α-(5'-hydroxypentyloxy)-pregn-5-ene-20-one (5) respectively in high yield. A detailed theoretical study supported by X-ray analysis of compounds 4 and 5 has been carried out. Conformational analysis of compounds 4 and 5 was done with the help of crystal structure, which crystallize out in orthorhombic form having P212121 space group. Structural characterization of compounds 4 and 5 was done with the aid of 1H, 13C NMR, IR, UV, ESI-MS and ESI-HRMS. The molecular geometries and vibrational frequencies for compounds 4 and 5 in the ground state were calculated using the Density functional theory (DFT) with 6-31G(d,p) basis set and compared with experimental data. 1H and 13C nuclear magnetic resonance magnetic shifts of 4 and 5 were calculated using GIAO method and compared with the experimental data. UV-Vis spectra of both the compounds were recorded and electronic properties such as HOMO-LUMO energies were calculated by time dependent TD-DFT approach. The compounds were screened for their anti-hyperlipidemic and anti-oxidant activity.

  12. A theoretical approach to the photochemical activation of matrix isolated aluminum atoms and their reaction with methane.

    PubMed

    Pacheco-Blas, M A; Novaro, O A; Pacheco-Sánchez, J H

    2010-11-01

    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 ((2)P:3s(2)3p(1)) and the lowest excited states ((2)S:3s(2)4s(1) and (2)D:3s(2)3d(1)) of an aluminum atom interacting with a methane molecule (CH(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 (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(4)) lower lying states (2)P and (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(3) intermediate that eventually leads to the final pair of products H+AlCH(3) and HAl+CH(3). PMID:21054032

  13. 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}.

  14. 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.

  15. 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

    2015-10-01

    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]. PMID:26412132

  16. Targeting histone methylation for cancer therapy: enzymes, inhibitors, biological activity and perspectives.

    PubMed

    Song, Yongcheng; Wu, Fangrui; Wu, Jingyu

    2016-01-01

    Post-translational methylation of histone lysine or arginine residues plays important roles in gene regulation and other physiological processes. Aberrant histone methylation caused by a gene mutation, translocation, or overexpression can often lead to initiation of a disease such as cancer. Small molecule inhibitors of such histone modifying enzymes that correct the abnormal methylation could be used as novel therapeutics for these diseases, or as chemical probes for investigation of epigenetics. Discovery and development of histone methylation modulators are in an early stage and undergo a rapid expansion in the past few years. A number of highly potent and selective compounds have been reported, together with extensive preclinical studies of their biological activity. Several compounds have been in clinical trials for safety, pharmacokinetics, and efficacy, targeting several types of cancer. This review summarizes the biochemistry, structures, and biology of cancer-relevant histone methylation modifying enzymes, small molecule inhibitors and their preclinical and clinical antitumor activities. Perspectives for targeting histone methylation for cancer therapy are also discussed. PMID:27316347

  17. 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. PMID:26945637

  18. Chapter 2: Theoretical Models for Understanding Physical Activity Behavior among Children and Adolescents--Social Cognitive Theory and Self-Determination Theory

    ERIC Educational Resources Information Center

    Motl, Robert W.

    2007-01-01

    The study of physical activity behavior in youth generally lacks a sufficient theoretical foundation for examining variables that influence that behavior. This is a major limitation because theory guides the search for determinants of behavior and the subsequent interplay between research findings and application. Theory offers a systematically…

  19. Physical Violence between Siblings: A Theoretical and Empirical Analysis

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  20. Understanding the relationships among HIV/AIDS-related stigma, health service utilization, and HIV prevalence and incidence in Sub-Saharan Africa: a multi-level theoretical perspective.

    PubMed

    Williams, Leslie D

    2014-03-01

    HIV-positive individuals often face community-wide discrimination or public shame and humiliation as a result of their HIV-status. In Sub-Saharan Africa, high HIV incidence coupled with unique cultural contexts make HIV-positive individuals particularly likely to experience this kind of HIV/AIDS-related (HAR) stigma. To date, there is a relatively small amount of high-quality empirical literature specific to HAR stigma in this context, supporting the notion that a better understanding of this phenomenon is needed to inform potential interventions. This paper provides a thorough review of the literature specific to HAR stigma in Sub-Saharan Africa, finding (a) qualitative support for the existence of important relationships between HAR stigma and health service utilization and barriers; (b) a need for more quantitative study of stigma and its relationships both to health service utilization and to HIV outcomes directly; and (c) a disconnect between methodological techniques used in this context-specific literature and well-known theories about stigma as a general phenomenon. This paper then draws from its empirical literature review, as well as from well-known theoretical frameworks from multiple disciplines, to propose a theoretical framework for the ecological and multilevel relationships among HAR stigma, health service utilization, and HIV outcomes in this context. PMID:24477769

  1. 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

  2. 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

  3. Peer education for advance care planning: volunteers’ perspectives on training and community engagement activities

    PubMed Central

    Seymour, Jane E; Almack, Kathryn; Kennedy, Sheila; Froggatt, Katherine

    2013-01-01

    Background Peer education by volunteers may aid attitudinal change, but there is little understanding of factors assisting the preparation of peer educators. This study contributes to conceptual understandings of how volunteers may be prepared to work as peer educators by drawing on an evaluation of a training programme for peer education for advance care planning (ACP). Objectives To report on volunteers’ perspectives on the peer education training programme, their feelings about assuming the role of volunteer peer educators and the community engagement activities with which they engaged during the year after training. To examine broader implications for peer education. Design Participatory action research employing mixed methods of data collection. Participants Twenty-four older volunteers and eight health and social care staff. Data collection methods Evaluative data were gathered from information provided during and at the end of training, a follow-up survey 4 months post-training; interviews and focus groups 6 and 12 months post-training. Findings Volunteers’ personal aims ranged from working within their communities to using what they had learnt within their own families. The personal impact of peer education was considerable. Two-thirds of volunteers reported community peer education activities 1 year after the training. Those who identified strongly with a community group had the most success. Conclusion We reflect on the extent to which the programme aided the development of ‘critical consciousness’ among the volunteers: a key factor in successful peer education programmes. More research is needed about the impact on uptake of ACP in communities. PMID:21615641

  4. Job Change in Perspective.

    ERIC Educational Resources Information Center

    Black, David R.; Loughead, Teri A.

    1990-01-01

    Defines current perspectives on voluntary job change, documents its prevalence in North America, lists positive and negative effects, and considers theoretical frameworks, counseling interventions, and research needs. (22 references) (SK)

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Theoretical study of cw to short pulse conversion in an active cw-injected ring cavity with a Yb3+:YAG amplifier.

    PubMed

    Huang, Zhiyun; Bourdet, Gilbert L

    2007-05-10

    The short laser pulse generated from an active cw-injected ring cavity with Yb3+:YAG crystal, which is treated as the homogeneously broadened amplifier, is studied theoretically. Based on the derived results, the impacts of the amplifier length, the seeding laser intensity and frequency, the pump intensity, the efficiency of the acousto-optic modulator (AOM), and the frequency shift generated by the AOM on the performance of the laser pulse are analyzed. PMID:17446920

  12. 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…

  13. Economic Aspects of Blindness and Low Vision: A New Perspective.

    ERIC Educational Resources Information Center

    Kirchner, C.

    1995-01-01

    This discussion of theoretical perspectives on disability's economic aspects urges development of better measures of productive activity by persons with blindness in paid and unpaid work; considers other personal characteristics that may account for dependence, such as old age or illness; and suggests that some costs are created by social…

  14. Structural, Spectroscopic, And Theoretical Elucidation of a Redox-Active Pincer-Type Ancillary Applied in Catalysis

    SciTech Connect

    Adhikari, D.; Mossin, S.; Basuli, F.; Huffman, J.C.; Szilagyi, R.K.; Meyer, K.; Mindiola, D.J.

    2009-05-11

    Pincer-type ligands are believed to be very robust scaffolds that can support multifarious functionalities as well as highly reactive metal motifs applied in organometallic chemistry, especially in the realm of catalysis. In this paper, we describe the redox and, therefore, noninnocent behavior of a PNP (PNP{sup -} = N[2-P(CHMe{sub 2}){sub 2}-4-methylphenyl]{sub 2}) pincer ancillary bound to nickel. A combination of structural, spectroscopic, and theoretical techniques suggests that this type of framework can house an electron hole when coordinated to Ni(II).

  15. 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

  16. 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.

  17. 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 design along…

  18. 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

  19. Synthesis and theoretical calculations of carbazole substituted chalcone urea derivatives and studies their polyphenol oxidase enzyme activity.

    PubMed

    Nixha, Arleta Rifati; Arslan, Mustafa; Atalay, Yusuf; Gençer, Nahit; Ergün, Adem; Arslan, Oktay

    2013-08-01

    Synthesis of carbazole substituted chalcone urea derivatives and their polyphenol oxidase enzyme activity effects on the diphenolase activity of banana tyrosinase were evaluated. Tyrosinase has been purified from banana on an affinity gel comprised of Sepharose 4B-L-tyrosine-p-aminobenzoic acid. The results showed that most of the compounds (3,4,5a,5d-h) inhibited and some of them (5c,5i-l) activated the tyrosinase enzyme activity. The molecular calculations were performed using Gaussian software for the synthesized compounds to explain the experimental results. PMID:22803668

  20. 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…

  1. The Institutional Perspective on School Improvement. Final Report.

    ERIC Educational Resources Information Center

    Clune, William H.

    The insights of various theoretical perspectives on school improvement can be integrated in a common framework called "the institutional perspective" when the sensitivity of each theoretical perspective to the nature of decision making for school improvement is taken into account. The institutional perspective thus generated considers the…

  2. 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

  3. 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

  4. Molecular orbital calculations, experimental and theoretical UV spectra of granulatimides and didemnimides, biologically active polycyclic heteroaromatic alkaloids from the ascidian Didemnum granulatum

    NASA Astrophysics Data System (ADS)

    Camargo, A. J.; Oliveira, J. H. H. L.; Trsic, M.; Berlinck, R. G. S.

    2001-01-01

    A detailed computational study was performed for compounds granulatimide, isogranulatimide, and didemnimides A, D, and E, using the semiempirical Austin model 1 quantum chemical method. The electronic features and structural parameters were confronted with the inhibition of the G2 cell cycle checkpoint of mammalian cancer cells. All compounds were submitted to a rigorous conformational analysis using the Tripos 5.2 force field implemented in the Spartan 5.01 program. The electronic density in specific regions of the molecules appears to play a pivotal role towards activity. The molecular planarity creates a broad negative electrostatic potential on the two sides of the active compounds (granulatimide and isogralulatimide) and a positive potential in their central core, while the non-planar compounds (didemnimides A, D, and E, which are inactive) present an asymmetric potential scattered over the molecules. These electrostatic potential features are likely to be the modulator of hydrophobicity or lipophilicity of the compounds, which appear correlated with activity. The hydrogen attached to the N atom of the pyrrole moiety of indole is more positive for active compounds than for the inactive molecules. The theoretical electronic spectra were obtained for all compounds using the configuration interaction method, with the AM1 routine. All transitions present π→π ∗ nature. The theoretical results are in good agreement with experimental values.

  5. 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.

  6. 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.

  7. [Activity and Future Perspective of Local Independent Clinical Trial Group (OGSG)].

    PubMed

    Tsujinaka, Toshimasa

    2016-04-01

    Osaka Gastrointestinal Cancer Chemotherapy Study Group (OGSG) was established in 2000 and has been conducting investigator initiated multi-institutional collaboration trials regarding the treatment of gastrointestinal cancer, especially using chemotherapeutic agents. Although organization of OGSG has been renovated to perform post-marketing clinical trials with high quality, OGSG is now facing severe financial crisis because of shortage of donation from pharmaceutical companies. Here, present problems and future perspectives are discussed. PMID:27220796

  8. 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. PMID:26743995

  9. 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…

  10. 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.

  11. Lipoic acid and dihydrolipoic acid. A comprehensive theoretical study of their antioxidant activity supported by available experimental kinetic data.

    PubMed

    Castañeda-Arriaga, Romina; Alvarez-Idaboy, J Raul

    2014-06-23

    The free radical scavenging activity of lipoic acid (LA) and dihydrolipoic acid (DHLA) has been studied in nonpolar and aqueous solutions, using the density functional theory and several oxygen centered radicals. It was found that lipoic acid is capable of scavenging only very reactive radicals, while the dehydrogenated form is an excellent scavenger via a hydrogen transfer mechanism. The environment plays an important role in the free radical scavenging activity of DHLA because in water it is deprotonated, and this enhances its activity. In particular, the reaction rate constant of DHLA in water with an HOO(•) radical is close to the diffusion limit. This has been explained on the basis of the strong H-bonding interactions found in the transition state, which involve the carboxylate moiety, and it might have implications for other biological systems in which this group is present. PMID:24881907

  12. Small-Pore Molecular Sieves SAPO-34 with Chabazite Structure: Theoretical Study of Silicon Incorporation and Interrelated Catalytic Activity

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Lewis, James; Liu, Zhongmin

    2011-03-01

    The catalytic conversion of methonal to olefin (MTO) has attracted attention both in industrial and academic fields. Strong evidence shows that small-pore molecular sieves with certain amount silicon incorporated (SAPO) present promising high catalytic activity in MTO conversion. Using DFT, we study the structural and electronic properties of chabazite SAPO-34. Although there are extensively experimental results show that silicon incorporation does not change the overall structure as the original AlPO structure, local structural changes are still created by silicon substitution, which probably accounted for the high catalytic activity. It is noted that the catalytic activity of SAPO-34 presents increasing trend along with the silicon incorporation amount increasing and maintain a flat peak even with more silicon incorporated. Hence, there is an optimal silicon incorporation amount which possibly yields the highest catalytic MTO conversion.

  13. 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. PMID:19339300

  14. A theoretical perspective on neutrino physics

    SciTech Connect

    Marciano, W.J. )

    1989-09-01

    A survey of sin{sup 2} {theta}{sub W}, {rho}, CKM matrix, and axial-isoscalar neutral current measurements via neutrino scattering is presented. Loop effects due to heavy top or a fourth generation are described. Neutrino oscillations are discussed in a three generation mixing framework and some motivation for {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillation searches is given. 15 refs., 1 tab.

  15. 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…

  16. 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

  17. [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. PMID:21834446

  18. Theoretical Perspectives on Chicano Personality Development.

    ERIC Educational Resources Information Center

    Garza, Raymond T.; Lipton, Jack P.

    1982-01-01

    Traditional theories of personality development are critically examined, emphasizing their applications to Mexican Americans. A preliminary framework for an interactional model of multiculturalism and personality development which can synthesize and integrate the effects of Chicano culture on the development of personality is proposed and…

  19. 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

  20. 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,…

  1. Affect and Problem Solving: Two Theoretical Perspectives.

    ERIC Educational Resources Information Center

    McLeod, Douglas B.

    Cognitive factors related to problem solving have been explored, but affective factors also play an important role in the teaching of mathematical problem solving. This paper outlines the theories of George Mandler and Bernard Weiner, providing a useful background for research related to affect and problem solving. Data related to the two theories…

  2. Theoretical Perspectives on the Internationalization of Firms

    ERIC Educational Resources Information Center

    Rask, Morten; Strandskov, Jesper; Hakonsson, Dorthe Dojbak

    2008-01-01

    The purpose of this article is to build a coherent framework of the four main theories relating to the internationalization of firms, in order to facilitate better business teaching and research. Yet, theories of the internationalization of firms are broad and rest on different underlying assumptions. With the purpose of clarifying the potential…

  3. 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. PMID:25779985

  4. The hydrolysis activity of Adenosine triphosphate in myosin: a theoretical analysis of anomeric effects and the nature of transition state

    PubMed Central

    Yang, Yang; Cui, Qiang

    2009-01-01

    Combined quantum mechanical/molecular mechanical (QM/MM) calculations with density functional theory are employed to analyze two issues related to the hydrolysis activity of Adenosine triphosphate (ATP) in myosin. First, we compare the geometrical properties and electronic structure of ATP in the open (post-rigor) and closed (pre-powerstroke) active sites of the myosin motor domain. Compared to both solution and the open active-site cases, the scissile Pγ-O3β bond of ATP in the closed active-site is shown to be substantially elongated. Natural Bond Orbital (NBO) analysis clearly shows that this structural feature is correlated with the stronger anomeric effects in the closed active site, which involve charge transfers from the lone-pairs in the non-bridging oxygen in the γ phosphate to the anti-bonding orbital of the scissile bond. However, an energetic analysis finds that the ATP molecule is not significantly destabilized by the Pγ-O3β bond elongation. Therefore, despite the notable perturbations in the geometry and electronic structure of ATP as its environment changes from solution to the hydrolysis-competent active site, ground state destabilization is unlikely to play a major role in enhancing the hydrolysis activity in myosin. Second, two-dimensional potential energy maps are used to better characterize the energetic landscape near the hydrolysis transition state. The results indicate that the transition state region is energetically flat and a range of structures representative of different mechanisms according to the classical nomenclature (e.g., “associative”, “dissociative” and “concerted”) are very close in energy. Therefore, at least in the case of ATP hydrolysis in myosin, the energetic distinction between different reaction mechanisms following the conventional nomenclature is likely small. This study highlights the importance of (i). explicitly evaluating the relevant energetic properties for determining whether a factor is essential

  5. The Evolution of Galaxies: an Infrared Perspective

    NASA Astrophysics Data System (ADS)

    Popescu, Cristina C.; Tuffs, Richard J.

    2010-06-01

    Understanding the infrared emission of galaxies is critical to observational and theoretical investigations of the condensation of galaxies out of the intergalactic medium and the conversion of gas into stars over cosmic time. From an observational perspective, about half of all photons emitted within galaxies are locally absorbed by dust grains, necessitating a self-consistent analysis of the panchromatic emission of galaxies to quantify star-formation and AGN activity as a function of epoch and environment. From a theoretical perspective, physical processes involving dust are expected to play a major role in regulating the accumulation of baryons in galaxies and their condensation into stars on scales ranging from Mpc down to sub-pc. All this requires a quantitative analysis of the interaction between dust, gas and radiation. Here we review progress in the modelling of some of these processes.

  6. 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)

  7. 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.

  8. 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.

  9. Synthesis, structural characterization, antimicrobial activities and theoretical investigations of some 4-(4-aminophenylsulfonyl) phenylimino) methyl)-4-(aryldiazenyl) phenol.

    PubMed

    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. PMID:27294547

  10. 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.

  11. 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

    2014-07-01

    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. PMID:24844618

  12. 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).

  13. A Theoretical-Experimental Study on the Structure and Activity of Certain Quinolones and the Interaction of Their Cu(II)-Complexes on a DNA Model

    PubMed Central

    Robles, J.; Martín-Polo, J.; Álvarez-Valtierra, L.; Hinojosa, L.

    2000-01-01

    Theoretical electronic Structure methods have been employed to study the structure and activity of certain (free) quinolones and the interaction of their Cu(II)-complexes on a DNA model (Rhodamine 6G (rhod)). As a manner of assessing the generated geometries, the nalidixic acid geometrical parameters obtained were tested against the crystallographic ones and it was found that the average error in the calculated geometries is small. The present study allows us to (1) Rationalize the observed differences in antibiotic activities through their electronic hardnesses. (2) Suggest a plausible mechanism of action for these drugs through formation of a reactive intermediate (or carrier) which would consist of a quinolone anion coordinated to an adequate metal center (Cu(II) in this study). (3) We find that, through this model of DNA (modeled with rhod) the interaction seems to be mediated by an effective π-π stacking. (4) Finally, an in vitro experiment was designed so that the intercalation process in DNA could be experimentally modeled as well. The quenching of the rhod fluorescence is proportional to the strength of the Cu(II)-complex-rhod interaction and therefore provides a quantitative measurement of the “intercalating” capacity of the quinolones and their copper complexes. These results agree well with the theoretical total adduct formation energies. PMID:18475962

  14. 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

  15. A theoretical study of the high-latitude winter F region at solar minimum for low magnetic activity

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    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.

  16. Theoretical insights on the catalytic activity and mechanism for oxygen reduction reaction at Fe and P codoped graphene.

    PubMed

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

    2016-05-14

    The non-precious metal graphene catalyst doped with Fe-Px are recently proposed as a promising candidate in substituting Pt for catalyzing oxygen reduction reaction (ORR) in fuel cells. Systematic DFT calculations are performed to investigate the catalytic activity and the ORR mechanism on the Fe-Px (x = 1-4) system in acid medium in this work. Our results indicated that the configuration with one Fe and two P atoms codoped at zigzag edge site (Fe-P2-zig-G) is the most stable, in excellent agreement with the experimental observation that the ratio of Fe and P is nearly 1 : 2. The four-electron reduction mechanism for ORR on the Fe-P2-zig-G is via the competing OOH hydrogenation pathways (to form either OH + OH or O + H2O). The rate determining step is the O2 hydrogenation with an energy barrier of 0.43 eV, much smaller that of calculated 0.80 eV for pure Pt. In addition, the highest energy barrier of the studied ORR mechanism is the O2 dissociation with an energy barrier of 0.70 eV, a value also smaller than that of pure Pt. This demonstrated that the zigzag edge site of the Fe-P2 codoped graphene should be active for the ORR. PMID:27094325

  17. Quantitative structure-activity relationship analysis of substituted arylazo pyridone dyes in photocatalytic system: Experimental and theoretical study.

    PubMed

    Dostanić, J; Lončarević, D; Zlatar, M; Vlahović, F; Jovanović, D M

    2016-10-01

    A series of arylazo pyridone dyes was synthesized by changing the type of the substituent group in the diazo moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The structural and electronic properties of the investigated dyes was calculated at the M062X/6-31+G(d,p) level of theory. The observed good linear correlations between atomic charges and Hammett σp constants provided a basis to discuss the transmission of electronic substituent effects through a dye framework. The reactivity of synthesized dyes was tested through their decolorization efficiency in TiO2 photocatalytic system (Degussa P-25). Quantitative structure-activity relationship analysis revealed a strong correlation between reactivity of investigated dyes and Hammett substituent constants. The reaction was facilitated by electron-withdrawing groups, and retarded by electron-donating ones. Quantum mechanical calculations was used in order to describe the mechanism of the photocatalytic oxidation reactions of investigated dyes and interpret their reactivities within the framework of the Density Functional Theory (DFT). According to DFT based reactivity descriptors, i.e. Fukui functions and local softness, the active site moves from azo nitrogen atom linked to benzene ring to pyridone carbon atom linked to azo bond, going from dyes with electron-donating groups to dyes with electron-withdrawing groups. PMID:27209516

  18. 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.

  19. 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.

  20. 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

  1. 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. PMID:22576733

  2. 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…

  3. Active performance of tetrahedral groups to SHG response: theoretical interpretations of Ge/Si-containing borate crystals.

    PubMed

    Li, Linping; Yang, Zhihua; Lei, Bing-Hua; Kong, Qingrong; Lee, Ming-Hsein; Zhang, Bingbing; Pan, Shilie; Zhang, Jun

    2016-02-17

    As potential candidates for deep-UV nonlinear optical (NLO) crystals, borosilicates and borogermanates, which contain NLO-active groups such as B-O, Si-O and Ge-O, have fascinated many scientists. The crystal structures, electronic structures and optical properties of seven borates in different B/R (R = Si, Ge) ratios have been studied using DFT methods. Through the SHG-density, we find that besides the recognized contribution of the π-conjugation configuration of BO3 to second harmonic generation (SHG), the tetrahedra have a non-negligible influence. This is because the non-bonding p orbitals of the bridging oxygen in the tetrahedra are observably closer to the Fermi level than those in BO3, which is observed in the PDOS of Rb4Ge3B6O17 and RbGeB3O7. This conclusion would be very meaningful in the understanding of the relationship between the crystal structure and nonlinear optical properties. PMID:26844983

  4. Correlation between theoretical descriptor and catalytic oxygen reduction activity of graphene supported palladium and palladium alloy electrocatalysts

    NASA Astrophysics Data System (ADS)

    Seo, Min Ho; Choi, Sung Mook; Lee, Dong Un; Kim, Won Bae; Chen, Zhongwei

    2015-12-01

    The oxygen reduction reaction, ORR, performances of graphene-supported palladium (Pd) and palladium alloys (Pd3X: X = Ag, Co and Fe) catalysts with highly dispersed catalyst particles are investigated in acidic and alkaline conditions using a rotating disk electrode, RDE. Graphene nanosheet, GNS, supported Pd based catalysts are fabricated without surfactant through the impregnation of Pd and 2nd metal precursors on GNS, leading to small and uniformly dispersed nanoparticles, even when high metal loading of up to 60 wt.% are deposited on supports. The ab-initio density functional theory, DFT, calculations, which are based on the d-band center theory, have been applied to correlate with the results of the ORR performances obtained by half-cell tests. Additionally, the cohesive energy, Ecoh, and dissolution potential, Um, for the Pd nanoparticles have been calculated to understand thermodynamic stability. To elucidate the d-band center shift, the Pd 3d5/2 core-level binding energies for Pd/GNS, Pd3Ag/GNS, Pd3Fe/GNS and Pd3Co/GNS have been investigated by X-ray photoelectron spectroscopy, XPS. The GNS-supported Pd, or Pd-based alloy-nanoparticle catalyst shows good ORR activity under acidic and alkaline conditions, suggesting it may offer potential replacement for Pt for use in cathode electrodes of anion-exchange membrane fuel cell, AEMFC, and acid based polymer electrolyte fuel cell, PEMFC.

  5. 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.

  6. 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

  7. Disentangling AGN and starburst activities in NGC 6240 from an X-ray perspective

    NASA Astrophysics Data System (ADS)

    Wang, Junfeng

    2016-02-01

    The circum-nuclear region in an active galaxy is often complex with presence of high excitation gas, collimated radio outflow, and star formation activities, besides the actively accreting supermassive black hole. The unique spatial resolving power of Chandra X-ray imaging spectroscopy enables more investigations to disentangle the active galactic nuclei and starburst activities. For galaxies in the throes of a violent merging event such as NGC6240, we were able to resolve the high temperature gas surrounding its binary active black holes and discovered a large scale soft X-ray halo.

  8. Case managers' and independent living counselors' perspectives on health promotion activities for individuals with physical and developmental disabilities.

    PubMed

    James, Aimee S; Shireman, Theresa I

    2010-01-01

    A fundamental component of maximizing the quality of life for individuals with disabilities is quality health care. We describe the perspectives of case managers and independent living counselors on the role of health promotion as a component of targeted case management services. Respondents held health promotion as an essential element of maximizing the quality of life for individuals with disabilities, although they spent more time on social services as compared to medical services. Their confidence in assisting the individuals they serve with respect to health promotion and disease management activities was demonstrably weaker than their reported knowledge levels for most items. Barriers to accessing those services might create this apparent disconnect between knowledge and confidence. PMID:21104516

  9. A theoretical study of O2 activation by the Au7-cluster on Mg(OH)2: roles of surface hydroxyls and hydroxyl defects.

    PubMed

    Jia, Chuanyi; Fan, Weiliu

    2015-11-11

    Using density functional theory (DFT) calculations, we investigated O2 activation by the Au7-cluster supported on the perfect and hydroxyl defective Mg(OH)2(0001) surface. It is revealed that hydroxyl groups on the perfect Mg(OH)2(0001) surface can not only enhance the stability of the Au7-cluster, but also help the adsorption of the O2 molecule through hydrogen-bonding interactions with the 2nd-layered interfacial Au sites. Density of states (DOS) analysis shows that the d-band centers of the 2nd-layered interfacial Au atoms are very close to the Fermi level, which thereby reduce the Pauli repulsion and promote the O2 adsorption. These two responses make the 2nd-layered interfacial Au atoms favor O2 activation. Interestingly, the surface hydrogen atoms activated by the 1st-layered Au atoms can facilitate the O2 dissociation process as well. Such a process is dynamically favorable and more inclined to occur at low temperatures compared to the direct dissociation process. Meanwhile, the hydroxyl defects of Mg(OH)2(0001) located right under the Au7-cluster can also up-shift the d-band centers of the surrounding Au atoms toward the Fermi level, enhancing its catalytic activity for O2 dissociation. In contrast, the d-band center of Au atoms surrounding the hydroxyl defect near the Au7-cluster exhibits an effective down-shift to lower energies, and therefore holds low activity. These results unveiled the roles of surface hydroxyls and hydroxyl defects on the Au/Mg(OH)2 catalyst in O2 activation and could provide a theoretical guidance for chemists to efficiently synthesize Au/hydroxide catalysts. PMID:26529519

  10. 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

  11. Physical Activity Status and Position of Governmental Employees in Changing Stage Based on the Trans-Theoretical Model in Hamadan, Iran.

    PubMed

    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

  12. 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

  13. Physical activity in older age: perspectives for healthy ageing and frailty.

    PubMed

    McPhee, Jamie S; French, David P; Jackson, Dean; Nazroo, James; Pendleton, Neil; Degens, Hans

    2016-06-01

    Regular physical activity helps to improve physical and mental functions as well as reverse some effects of chronic disease to keep older people mobile and independent. Despite the highly publicised benefits of physical activity, the overwhelming majority of older people in the United Kingdom do not meet the minimum physical activity levels needed to maintain health. The sedentary lifestyles that predominate in older age results in premature onset of ill health, disease and frailty. Local authorities have a responsibility to promote physical activity amongst older people, but knowing how to stimulate regular activity at the population-level is challenging. The physiological rationale for physical activity, risks of adverse events, societal and psychological factors are discussed with a view to inform public health initiatives for the relatively healthy older person as well as those with physical frailty. The evidence shows that regular physical activity is safe for healthy and for frail older people and the risks of developing major cardiovascular and metabolic diseases, obesity, falls, cognitive impairments, osteoporosis and muscular weakness are decreased by regularly completing activities ranging from low intensity walking through to more vigorous sports and resistance exercises. Yet, participation in physical activities remains low amongst older adults, particularly those living in less affluent areas. Older people may be encouraged to increase their activities if influenced by clinicians, family or friends, keeping costs low and enjoyment high, facilitating group-based activities and raising self-efficacy for exercise. PMID:26936444

  14. Perspectives on physical activity among immigrants and refugees to a small urban community in Minnesota

    PubMed Central

    Wieland, Mark L.; Tiedje, Kristina; Meiers, Sonja J.; Mohamed, Ahmed A.; Formea, Christine M.; Ridgeway, Jennifer L.; Asiedu, Gladys B.; Boyum, Ginny; Weis, Jennifer A.; Nigon, Julie A.; Patten, Christi; Sia, Irene G.

    2013-01-01

    BACKGROUND Immigrants and refugees to the United States exhibit relatively low levels of physical activity, but reasons for this disparity are poorly understood. METHODS 16 gender and age-stratified focus groups were conducted among 127 participants from heterogenous immigrant and refugee groups (Cambodian, Mexican, Somali, Sudanese) in a small Minnesota urban community. RESULTS We found many similarities in perceived barriers and facilitators to physical activity between heterogeneous immigrant and refugee groups. While the benefits of physical activity were widely acknowledged, lack of familiarity and comfort with taking the first steps towards being physically active were the most significant barriers to physical activity. Participants described being motivated by social support from family, friends, and communities to be physically active. DISCUSSION Our findings suggest that shared experiences of immigration and associated social, economic, and linguistic factors influence how physical activity is understood, conceptualized and practiced. PMID:24052480

  15. 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.

  16. 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 organizational…

  17. Mechanisms of trichloramine removal with activated carbon: stoichiometric analysis with isotopically labeled trichloramine and theoretical analysis with a diffusion-reaction model.

    PubMed

    Sakuma, Miki; Matsushita, Taku; Matsui, Yoshihiko; Aki, Tomoko; Isaka, Masahito; Shirasaki, Nobutaka

    2015-01-01

    This study investigated the mechanism by which activated carbon removes trichloramine, a byproduct of water treatment that has a strongly offensive chlorinous odor. A stoichiometrical mass balance for ¹⁵N before and after activated carbon treatment of laboratory-prepared ¹⁵N-labeled trichloramine solutions clearly revealed that the mechanism of trichloramine removal with activated carbon was not adsorption but rather reductive decomposition to nitrogen gas. There was a weak positive correlation between the surface decomposition rate constant of trichloramine and the concentration of basic functional groups on the surface of the carbon particles, the suggestion being that the trichloramine may have been reduced by sulfhydryl groups (-SH) on the activated carbon surface. Efficient decomposition of trichloramine was achieved with super powdered activated carbon (SPAC), which was prepared by pulverization of commercially available PAC into very fine particles less than 1 μm in diameter. SPAC could decompose trichloramine selectively, even when trichloramine and free chlorine were present simultaneously in water, the indication being that the strong disinfection capability of residual free chlorine could be retained even after trichloramine was effectively decomposed. The residual ratio of trichloramine after carbon contact increased somewhat at low water temperatures of 1-5 °C. At these low temperatures, biological treatment, the traditional method for control of a major trichloramine precursor (ammonium nitrogen), is inefficient. Even at these low temperatures, SPAC could reduce the trichloramine concentration to an acceptable level. A theoretical analysis with a diffusion-reaction model developed in the present study revealed that the increase in the trichloramine residual with decreasing water temperature was attributable to the temperature dependence of the rate of the reductive reaction rather than to the temperature dependence of the diffusive mass

  18. Perspectives of pregnant and postpartum latino women on diabetes, physical activity, and health.

    PubMed

    Kieffer, Edith C; Willis, Sharla K; Arellano, Natalia; Guzman, Ricardo

    2002-10-01

    Impaired glucose tolerance and diabetes are prevalent among Latino women of childbearing age. Physical activity during and after pregnancy may contribute to weight control and improved metabolic status, but recommended activities may not be perceived as appropriate or feasible. To plan realistic and acceptable interventions, pregnant and postpartum Latino women in Detroit met in a focus group series to discuss their beliefs about diabetes and factors influencing their participation in regular physical activity during pregnancy and postpartum. Women believed that diabetes was primarily related to heredity and diet but not to physical activity. Exercise was believed to reduce stress and improve general health. Women suggested an organized group intervention, in a respected location, that offered safe physical activities within the context of a variety of activities for women and children. This strategy reduced concerns about safety and social acceptability while addressing their primary interest in social support. PMID:12238699

  19. 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…

  20. 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…

  1. Type 2 diabetes and dog walking: patients' longitudinal perspectives about implementing and sustaining physical activity

    PubMed Central

    Peel, Elizabeth; Douglas, Margaret; Parry, Odette; Lawton, Julia

    2010-01-01

    Background Physical activity is particularly important for people with type 2 diabetes, as evidence suggests that any reduction in sedentary time is good for metabolic health. Aim To explore type 2 diabetes patients' talk about implementing and sustaining physical activity. Design of study Longitudinal, qualitative study using repeat in-depth interviews with 20 patients over 4 years following clinical diagnosis. Setting Patients were recruited from 16 general practices and three hospitals across Lothian, Scotland. Results Discussion, and salience, of physical activity was marginal in patient accounts of their diabetes management. Patients claimed to have only received vague and non-specific guidance about physical activity from health professionals, and emphasised a perceived lack of interest and encouragement. Aside from walking, physical activities which were adopted tended to attenuate over time. Patients' accounts revealed how walking a dog assisted this kind of activity maintenance over time. Three main themes are highlighted in the analysis: 1) incidental walking; 2) incremental physical activity gains; and 3) augmenting physical activity maintenance. The problems arising from walking without a dog (for example, lack of motivation) are also examined. Conclusion Asking patients about pet preferences might seem tangential to medical interactions. However, encouraging dog walking or identifying another interest that promotes a regular commitment to undertake physical activity may yield long-term health benefits. PMID:20822690

  2. Future Directions of Inquiry in Adapted Physical Activity.

    ERIC Educational Resources Information Center

    Reid, Greg

    2000-01-01

    Sketches some future trends of inquiry in adapted physical activity. These include investigation into ethics in adapted physical activity. Empirically based issues of inquiry include physical activity as a dependent measure, diverse and changing populations, theoretical and applied research, nomothetic and idiographic research perspectives,…

  3. 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…

  4. 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…

  5. 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…

  6. 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…

  7. Science Teachers' Typology of CPD Activities: A Socio-Constructivist Perspective

    ERIC Educational Resources Information Center

    EL-Deghaidy, Heba; Mansour, Nasser; Alshamrani, Saeed

    2015-01-01

    This study presents a typology of continuing professional development (CPD) activities and provides a discussion related to each. The typology includes 2 main themes, which investigate the various types of activities and the content presented in CPD programmes. The study used qualitative methods (open-ended questionnaires in addition to…

  8. "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 physical…

  9. Policy, Pedagogy, and Priorities: Exploring Stakeholder Perspectives on Active Learning in the Maldives

    ERIC Educational Resources Information Center

    Di Biase, Rhonda

    2015-01-01

    Challenges of implementing active-learning reform have been reported across a range of countries and include the need for greater attention to contextual factors and practical realities in the reform process. This study investigates how teachers enact active-learning pedagogy within the Maldives. Using design-based research, it explores--through…

  10. A Developmental Perspective on the Role of Motor Skill Competence in Physical Activity: An Emergent Relationship

    ERIC Educational Resources Information Center

    Stodden, David F.; Goodway, Jacqueline D.; Langendorfer, Stephen J.; Roberton, Mary Ann; Rudisill, Mary E.; Garcia, Clersida; Garcia, Luis E.

    2008-01-01

    Although significant attention has been paid to promoting the importance of physical activity in children, adolescents, and adults, we do not currently understand how to promote sustained physical activity levels throughout the lifespan. We contend that previous research has failed to consider the dynamic and synergistic role that motor skill…

  11. [Active aging from the perspective of aged individuals who are functionally independent].

    PubMed

    Ferreira, Olivia Galvão Lucena; Maciel, Silvana Carneiro; Silva, Antonia Oliveira; dos Santos, Walberto Silva; Moreira, Maria Adelaide Silva P

    2010-12-01

    The objective of this study was to identify the social representations of the elderly regarding active aging. Semi-structured interviews were performed with 100 functionally independent aged individuals from João Pessoa, Paraiba, Brazil. The data was organized and analyzed using Alceste software. Results showed that the aged individuals' statements about active aging are permeated with positive contents. However, when aging is not associated with the word active, it is still represented as losses and disabilities. Despite the existence of losses during the process, active aging should be encouraged among the elderly, as it means living a quality, plentiful life. Maintaining the elderly functionally independent is the first step to achieving active aging and thus improving their quality of life. PMID:21337791

  12. Study Approaches, Processes and Strategies: Are Three Perspectives Better than One?

    ERIC Educational Resources Information Center

    Speth, Carol; Brown, Robert

    1988-01-01

    Describes study of 383 college students in educational psychology classes that was designed to determine how students describe study activities. Completed inventories are compared from three theoretical perspectives: cognitive processes, approaches to learning, and autonomous studying, and factor analyses are explained. (25 references) (LRW)

  13. 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…

  14. 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…

  15. Perspective: agency and activism: rethinking health advocacy in the medical profession.

    PubMed

    Dobson, Sarah; Voyer, Stéphane; Regehr, Glenn

    2012-09-01

    Health advocacy is being formalized as a professional activity for physicians across North America, but the accommodation of this activity into conceptions of daily practice has been controversial and confusing. There appears to be a lack of clarity around what a physician should do as a health advocate and how this should manifest in daily practice. In this article, the authors explore how the medical community has characterized the health advocate role and the roots of the debates regarding its place within training and practice, using the example of the CanMEDS Health Advocate Role. They argue that the confusion might be a result of subsuming two distinct activities, agency and activism, under the rubric of health advocacy. They propose that these activities and their associated skills are sufficiently distinct as to merit separate discussions. Agency involves advancing the health of individual patients ("working the system"), and activism involves advancing the health of communities and populations ("changing the system"). The authors suggest that distinguishing between agency and activism within health advocacy provides opportunities to explore their distinct goals and skill sets in a manner that will advance the debate about health advocacy, a conversation that remains critically important to the medical profession. PMID:22836842

  16. Does Improving Exercise Capacity and Daily Activity Represent the Holistic Perspective of a New COPD Approach?

    PubMed

    Di Marco, Fabiano; Santus, Pierachille; Sotgiu, Giovanni; Blasi, Francesco; Centanni, Stefano

    2015-01-01

    In COPD patients a reduced daily activity has been well documented, resulting from both respiratory and non-respiratory manifestations of the disease. An evaluation by multisensory armband has confirmed that daily physical activity is mainly associated with dynamic hyperinflation, regardless of COPD severity. This aspect is crucial, since exercise capacity is closely correlated to life expectancy. Notwithstanding the causal key role of lung impairment in the patient's symptoms, some authors have suggested that other factors, such as systemic inflammation and co-morbidities, have an important role, particularly as mortality risk factors. Many studies suggest the efficacy of bronchodilators and rehabilitation in improving exercise capacity, and, speaking in terms of daily life, in increasing the number of days in which patients are able to perform their usual activities. On this evidence, the first aim in the management of COPD should be to improve exercise capacity and daily activity since these outcomes have direct effects on patients' quality of life, co-morbidities (heart and metabolic diseases), and prognosis. Thus, improving physical activity represents a modern approach aimed at dealing with both pulmonary and systemic manifestations of the disease. It is however worth of notice to remember that in patients affected by COPD the relationship between the improvement of "potential" exercise capacity and daily physical activity has been found to be only moderate to weak. Obtaining a significant behavior modification with regard to daily physical activity, together with the optimization of therapy thus represents currently the true challenge. PMID:26457460

  17. Empirical and theoretical investigation of the noise performance of indirect detection, active matrix flat-panel imagers (AMFPIs) for diagnostic radiology.

    PubMed

    Siewerdsen, J H; Antonuk, L E; el-Mohri, Y; Yorkston, J; Huang, W; Boudry, J M; Cunningham, I A

    1997-01-01

    Noise properties of active matrix, flat-panel imagers under conditions relevant to diagnostic radiology are investigated. These studies focus on imagers based upon arrays with pixels incorporating a discrete photodiode coupled to a thin-film transistor, both fabricated from hydrogenated amorphous silicon. These optically sensitive arrays are operated with an overlying x-ray converter to allow indirect detection of incident x rays. External electronics, including gate driver circuits and preamplification circuits, are also required to operate the arrays. A theoretical model describing the signal and noise transfer properties of the imagers under conditions relevant to diagnostic radiography, fluoroscopy, and mammography is developed. This frequency-dependent model is based upon a cascaded systems analysis wherein the imager is conceptually divided into a series of stages having intrinsic gain and spreading properties. Predictions from the model are compared with x-ray sensitivity and noise measurements obtained from individual pixels from an imager with a pixel format of 1536 x 1920 pixels at a pixel pitch of 127 microns. The model is shown to be in excellent agreement with measurements obtained with diagnostic x rays using various phosphor screens. The model is used to explore the potential performance of existing and hypothetical imagers for application in radiography, fluoroscopy, and mammography as a function of exposure, additive noise, and fill factor. These theoretical predictions suggest that imagers of this general design incorporating a CsI: Tl intensifying screen can be optimized to provide detective quantum efficiency (DQE) superior to existing screen-film and storage phosphor systems for general radiography and mammography. For fluoroscopy, the model predicts that with further optimization of a-Si:H imagers, DQE performance approaching that of the best x-ray image intensifier systems may be possible. The results of this analysis suggest strategies for

  18. Understanding the challenges to facilitating active learning in the resident conferences: a qualitative study of internal medicine faculty and resident perspectives

    PubMed Central

    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

  19. 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. PMID:25232675

  20. Baroreflex Activation Therapy in Heart Failure With Reduced Ejection Fraction: Available Data and Future Perspective.

    PubMed

    Halbach, Marcel; Fritz, Thorsten; Madershahian, Navid; Pfister, Roman; Reuter, Hannes

    2016-04-01

    Progression of heart failure with reduced ejection fraction (HFrEF) is promoted by sympathovagal imbalance. Baroreflex activation therapy, i.e., electrical stimulation of baroreceptors at the carotid sinus, can restore sympathovagal balance. Large animal studies of baroreflex activation therapy revealed improvements in cardiac function, susceptibility to ventricular arrhythmias, and a survival benefit as compared to untreated controls. Recently, the first randomized and controlled trial of optimal medical and device therapy alone or plus baroreflex activation therapy in patients suffering from HFrEF was published. It demonstrated a reasonable safety profile in this severely ill patient population. Moreover, the study found significant improvements in New York Heart Association class, quality of life, 6-min walk distance, and NT-proBNP levels. This review provides an overview on baroreflex activation therapy for the treatment of HFrEF-from the concept and preclinical findings to most recent clinical data and upcoming trials. PMID:26879389

  1. Learning Science in a First Grade Science Activity: A Vygotskian Perspective.

    ERIC Educational Resources Information Center

    Shepardson, Daniel P.

    1999-01-01

    Synthesizes the key aspects of Vygotsky's sociocultural theory of learning. Interprets classroom vignettes and child interviews from a first-grade science activity in light of Vygotsky's theory. (Author/CCM)

  2. 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

  3. Revisiting the mechanism of coagulation factor XIII activation and regulation from a structure/functional perspective.

    PubMed

    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

  4. 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. PMID:25617423

  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. 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

  7. 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

  8. Leisure Engagement: Medical Conditions, Mobility Difficulties, and Activity Limitations—A Later Life Perspective

    PubMed Central

    Nilsson, Ingeborg; Nyqvist, Fredrica; Gustafson, Yngve; Nygård, Mikael

    2015-01-01

    Objectives. This study aims to investigate the impact of medical conditions, mobility difficulties, and activity limitations on older people's engagement in leisure activities. Methods. The analyses are based on a cross regional survey carried out in 2010 in the Bothnia region (Northern Sweden and Western Finland). A posted questionnaire, which included questions on different aspects of leisure engagement, medical history, and health, was sent out to older persons in the region. The final sample consisted of 5435 persons aged 65, 70, 75, and 80 years. The data was analyzed by using ordinary least squares (OLS) multivariate regression. Results. The most important predictor of leisure engagement abstention among older people is the prevalence of activity limitations, whereas mobility difficulties and medical conditions play less important roles. The strong negative association between activity limitations and leisure engagement remains significant even after we control for individual, sociodemographic characteristics, and country. Discussion. This study provides a window into leisure engagement in later life and factors influencing the magnitude of engagement in leisure activities. PMID:26346706

  9. Conformational flexibility and structural dynamics in GPCR-mediated G protein activation: a perspective

    PubMed Central

    Preininger, Anita M.; Meiler, Jens; Hamm, Heidi

    2013-01-01

    Structure and dynamics of G proteins and their cognate receptors, both alone and in complex, are becoming increasingly accessible to experimental techniques. Understanding the conformational changes and timelines which govern these changes can lead to new insights into the processes of ligand binding and associated G protein activation. Experimental systems may involve the use of, or otherwise stabilize, non-native environments. This can complicate our understanding of structural and dynamical features of processes such as the ionic lock, Tryptophan toggle, and G protein flexibility. While elements in the receptor’s transmembrane helices and the C-terminal α5 helix of Gα undergo well defined structural changes, regions subject to conformational flexibility may be important in fine-tuning the interactions between activated receptors and G proteins. The pairing of computational and experimental approaches will continue to provide powerful tools to probe the conformation and dynamics of receptor-mediated G protein activation. PMID:23602809

  10. [Clinical relevance of antidepressant-induced activation syndrome: from a perspective of bipolar spectrum disorder].

    PubMed

    Tanaka, Teruaki; Inoue, Takeshi; Suzuki, Katsuji; Kitaichi, Yuji; Masui, Takuya; Denda, Kenzo; Koyama, Tsukasa

    2007-01-01

    Recent concerns have been raised regarding whether antidepressants, especially selective serotonin reuptake inhibitors (SSRIs) might increase suicidal tendencies and intense debate-rages over the pros and cons of their use. Although systematic reviews and population-based studies have been conducted, a consensus on this association remains to be established. Subsequently, the concept of so-called 'activation syndrome' associated with antidepressants has been accepted without its adequate verification. In the present report, we present our experience of seven cases considered of having 'activation syndrome' brought on by antidepressants, and examine its clinical relevance to bipolar spectrum disorder (Ghaemi, et al., 2001) both symptomatologically and diagnostically. Five patients, diagnosed as having major depressive disorder according to the diagnostic manual (DSM-IV), met the criteria of bipolar spectrum disorder and suffered from activation syndrome following the administration of SSRIs, mainly paroxetine. Similarly, hypomania developed in all five cases with depression; the diagnostic criteria of a hypomanic episode were not met. In the remaining two patients, who were both diagnosed with bipolar disorder, one showed irritability and insomnia through imipramine use, and the another developed a hypomanic and/or a mixed state after the co-administration of fluvoxamine and trazodone. From the results of our examination, 'bipolarity', which is the pivotal factor of bipolar spectrum, might exist behind the phenomenon recognized as activation syndrome, and be revealed by antidepressant treatment, just like manic switching. Moreover, the various problems encountered in the current practice of treating mood disorders, including unipolar-bipolar dichotomy, manic switching by antidepressants, and narrow criteria for a mixed episode, were pointed out a new through this concept of activation syndrome. Actually, the understanding of activation syndrome clinically leads to

  11. Australian perspective regarding recommendations for physical activity and exercise rehabilitation in pulmonary arterial hypertension

    PubMed Central

    Fowler, Robin; Jenkins, Sue; Maiorana, Andrew; Gain, Kevin; O’Driscoll, Gerry; Gabbay, Eli

    2011-01-01

    Aim To determine the opinion of health care professionals within Australia, regarding acceptable levels of exertion and symptoms, and referral for exercise rehabilitation in patients with pulmonary arterial hypertension (PAH). Method In 2010, 76 health care professionals at a specialist pulmonary hypertension meeting in Australia were surveyed using a self-administered questionnaire. The questionnaire included case studies of patients with PAH in World Health Organization (WHO) functional classes II–IV. For each case study, respondents were asked to report their opinion regarding the acceptable level of exertion and symptoms during daily activities, and whether they would refer the patient for exercise rehabilitation. Three additional questions asked about advice in relation to four specific physical activities. Results The response rate was 70% (n = 53). Overall, 58% of respondents recommended patients undertake daily activities ‘as tolerated’. There was no consensus regarding acceptable levels of breathlessness or fatigue, but the majority of respondents considered patients should have no chest pain (73%) and no more than mild light-headedness (92%) during daily activities. Overall, 63% of respondents would have referred patients for exercise rehabilitation. There was little difference in opinion regarding the acceptable level of exertion or symptoms, or referral for exercise rehabilitation, according to functional class. However, the patients’ functional class did influence the advice given regarding the specific physical activities. Conclusion In 2010, there were inconsistencies between individual health care professionals within Australia regarding appropriate levels of physical exertion and acceptable symptoms during daily activities. Almost two-thirds of the respondents reported they would refer patients for exercise rehabilitation. PMID:22247620

  12. 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 Bois and…

  13. 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. PMID:22288995

  14. 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…

  15. School Engagement among Aboriginal Students in Northern Canada: Perspectives From Activity Settings Theory

    ERIC Educational Resources Information Center

    Davison, Colleen M.; Hawe, Penelope

    2012-01-01

    Background: Educational disengagement is a public health concern among Aboriginal populations in many countries. It has been investigated previously in a variety of ways, with the conventional focus being on the children themselves. Activity settings are events and places, theorized in terms of their symbols, roles, time frame, funds, people, and…

  16. 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...

  17. Socio-Cultural Context for Online Learning: A Case Study Viewed from Activity Theory Perspective

    ERIC Educational Resources Information Center

    Liu, Xiaojing

    2004-01-01

    The complexities of digital age pose challenge to existing instruction technology theory as it applies to a distance learning environment. Through the lens of Activity Theory, this study takes a broad picture of an online course and examines the socio-cultural factors affecting the success of a distance course as well as their complex…

  18. Physical Education Lessons and Physical Activity Intentions within Spanish Secondary Schools: A Self-Determination Perspective

    ERIC Educational Resources Information Center

    Sanchez-Oliva, David; Sanchez-Miguel, Pedro Antonio; Leo, Francisco Miguel; Kinnafick, Florence-Emilie; García-Calvo, Tomás

    2014-01-01

    Grounded in Self-Determination Theory, the purpose of this study was to analyze how motivational processes within Physical Education classes can predict intention to participate in sport or physical activity outside of the school curriculum. Participants included 1,692 Spanish students aged 12-16 years (M = 13.34; SD = 0.76) who participated in…

  19. Discovery and structure activity relationships of 2-pyrazolines derived from chalcones from a pest management perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthesis of chalcones and 2-pyrazoline derivatives has been an active field of research due to the established pharmacological effects of these compounds. In this study, a series of chalcone (1a-i), 2-pyrazoline-1-carbothioamides (2a-i) and 2-pyrazoline-1-carboxamide derivatives (3a-g) were synthes...

  20. Students´ Perspectives on eLearning Activities in Person-Centered, Blended Learning Settings

    ERIC Educational Resources Information Center

    Haselberger, David; Motsching, Renate

    2016-01-01

    Blended or hybrid learning has become a frequent practice in higher education. In this article our primary research interest was to find out how students perceived eLearning activities in blended learning courses based on the person-centered paradigm. Through analyzing the content of a series of semi-structured interviews we found out that…