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Sample records for physical realism stereochemistry

  1. Structural realism beyond physics.

    PubMed

    Tulodziecki, Dana

    2016-10-01

    The main purpose of this paper is to test structural realism against (one example from) the historical record. I begin by laying out an existing challenge to structural realism - that of providing an example of a theory exhibiting successful structures that were abandoned - and show that this challenge can be met by the miasma theory of disease. However, rather than concluding that this is an outright counterexample to structural realism, I use this case to show why it is that structural realism, in its current form, has trouble dealing with theories outside physics. I end by making some concrete suggestions for structural realists to pursue if, indeed, they are serious about extending structural realism to other domains.

  2. Does Quantum Physics Refute Realism, Materialism and Determinism?

    NASA Astrophysics Data System (ADS)

    Bunge, Mario

    2012-10-01

    It is argued that the correct answer to the three questions in the title is "no": that the theses being denied derive from traditional philosophy, not from the way the quantum theories are used. For example, the calculation of the energy spectrum of an atom assumes the autonomous existence of the atom, rather than its dependence upon the observer. However, it is also suggested that the problem has been unnecessarily complicated by a careless use of the terms `realism', `materialism', and `determinism'. Precise definitions of these words are proposed.

  3. Shifting to structures in physics and biology: a prophylactic for promiscuous realism.

    PubMed

    French, Steven

    2011-06-01

    Within the philosophy of science, the realism debate has been revitalised by the development of forms of structural realism. These urge a shift in focus from the object oriented ontologies that come and go through the history of science to the structures that remain through theory change. Such views have typically been elaborated in the context of theories of physics and are motivated by, first of all, the presence within such theories of mathematical equations that allow straightforward representation of the relevant structures; and secondly, the implications of such theories for the individuality and identity of putative objects. My aim in this paper is to explore the possibility of extending such views to biological theories. An obvious concern is that within the context of the latter it is typically insisted that we cannot find the kinds of highly mathematised structures that structural realism can point to in physics. I shall indicate how the model-theoretic approach to theories might help allay such concerns. Furthermore, issues of identity and individuality also arise within biology. Thus Dupré has recently noted that there exists a 'General Problem of Biological Individuality' which relates to the issue of how one divides 'massively integrated and interconnected' systems into discrete components. In response Dupré advocates a form of 'Promiscuous Realism' that holds, for example, that there is no unique way of dividing the phylogenetic tree into kinds. Instead I shall urge serious consideration of those aspects of the work of Dupré and others that lean towards a structuralist interpretation. By doing so I hope to suggest possible ways in which a structuralist stance might be extended to biology.

  4. For or against structural realism? A verdict from high energy physics

    NASA Astrophysics Data System (ADS)

    Nounou, Antigone M.

    2015-02-01

    When it comes to supporting the main ontic structural realist thesis, that we are better off with a metaphysics purged of objects, its proponents have to meet several challenges, three of which are to ensure that objects can be recast in terms of structure alone at both the level of theory and the level of ontology, to justify on physical grounds that structure exists in the world in a way that affects the goings-on in it, and to show that the relation between objects and structure is non-reciprocal, so that structure is ontologically prior to objects but not the converse. Assuming-tacitly or explicitly-that the objects of physics can be thus recast using symmetry group structure, supporters of the thesis have, therefore, to meet the remaining challenges. The present paper discusses and contests two such attempts, which typify arguments in favor of ontic structural realism from high-energy physics.

  5. Practical Stereochemistry.

    PubMed

    Kellogg, Richard M

    2017-03-01

    The relationship between fundamental and applied is often uneasy, particularly in modern political climates. A familiar political view, aimed negatively at the scientific community, is that the former is a waste of money whereas the latter gives value for investment. The answer that fundamental is required as the basis for practical suffers from the fact that the timelines between fundamental and practical are often long and the routes contorted and unexpected. This has been my experience. In this Account, examples are given from the research in which I have been involved wherein quite fundamental considerations have led to various applications. The longer the time, the clearer and broader the relationship. Fundamental can and does lead to application. They need and depend on each other. I have seen this both from the side of academia and from small companies. In the course of the past 40 plus years, I have been involved in various aspects of stereochemistry and, in particular, chirality. It has been rewarding to see that several of the developments, most originally grounded in fundamental research considerations, have been used in the chemical community and given new dimensions and often practical applications by others. In this Account, a path-not planned deliberately by me-from orbital symmetry and Woodward-Hoffmann rules through crown ethers to conformational analysis to diastereomeric resolutions to deracemizations powered by Ostwald ripening and the Gibbs-Thomson effect to nucleation to helicenes is described. In order of discussion, the orbital symmetry aspects have via an unusual and unpredicted path has resulted in, among other things, a synthesis of hindered alkenes useful for the production of molecular motors. The crown ether aspects led to discovery of the utility of cesium salts particularly for racemization sensitive nucleophilic substitutions. Work on diastereomeric resolutions has concentrated on the mechanistic as well as practical

  6. Realism vs. Constructivism in Contemporary Physics: The Impact of the Debate on the Understanding of Quantum Theory and Its Instructional Process

    ERIC Educational Resources Information Center

    Karakostas, Vassilios; Hadzidaki, Pandora

    2005-01-01

    In the present study we attempt to incorporate the philosophical dialogue about physical reality into the instructional process of quantum mechanics. Taking into account that both scientific realism and constructivism represent, on the basis of a rather broad spectrum, prevalent philosophical currents in the domain of science education, the…

  7. A Quiz on Stereochemistry.

    ERIC Educational Resources Information Center

    Ghosh, Abhik

    1987-01-01

    Presents five problems on organic stereochemistry in the form of an open-book quiz meant for senior undergraduates and graduate students in chemistry. Provides some acceptable solutions to the problems. (TW)

  8. Extensional scientific realism vs. intensional scientific realism.

    PubMed

    Park, Seungbae

    2016-10-01

    Extensional scientific realism is the view that each believable scientific theory is supported by the unique first-order evidence for it and that if we want to believe that it is true, we should rely on its unique first-order evidence. In contrast, intensional scientific realism is the view that all believable scientific theories have a common feature and that we should rely on it to determine whether a theory is believable or not. Fitzpatrick argues that extensional realism is immune, while intensional realism is not, to the pessimistic induction. I reply that if extensional realism overcomes the pessimistic induction at all, that is because it implicitly relies on the theoretical resource of intensional realism. I also argue that extensional realism, by nature, cannot embed a criterion for distinguishing between believable and unbelievable theories.

  9. Color realism and color science.

    PubMed

    Byrne, Alex; Hilbert, David R

    2003-02-01

    The target article is an attempt to make some progress on the problem of color realism. Are objects colored? And what is the nature of the color properties? We defend the view that physical objects (for instance, tomatoes, radishes, and rubies) are colored, and that colors are physical properties, specifically, types of reflectance. This is probably a minority opinion, at least among color scientists. Textbooks frequently claim that physical objects are not colored, and that the colors are "subjective" or "in the mind." The article has two other purposes: First, to introduce an interdisciplinary audience to some distinctively philosophical tools that are useful in tackling the problem of color realism and, second, to clarify the various positions and central arguments in the debate. The first part explains the problem of color realism and makes some useful distinctions. These distinctions are then used to expose various confusions that often prevent people from seeing that the issues are genuine and difficult, and that the problem of color realism ought to be of interest to anyone working in the field of color science. The second part explains the various leading answers to the problem of color realism, and (briefly) argues that all views other than our own have serious difficulties or are unmotivated. The third part explains and motivates our own view, that colors are types of reflectances and defends it against objections made in the recent literature that are often taken as fatal.

  10. Quantum mechanics is compatible with realism

    SciTech Connect

    Burgos, M.E.

    1987-08-01

    A new paradox of quantum mechanics has recently been proposed by an author claiming that any attempt to inject realism in physical theory is bound to lead to inconsistencies. In this paper the author shows that the mentioned paradox is not such a one and that at present there are no reasons to reject realism.

  11. Mario Bunge's Scientific Realism

    NASA Astrophysics Data System (ADS)

    Cordero, Alberto

    2012-10-01

    This paper presents and comments on Mario Bunge's scientific realism. After a brief introduction in Sects. 1 and 2 outlines Bunge's conception of realism. Focusing on the case of quantum mechanics, Sect. 3 explores how his approach plays out for problematic theories. Section 4 comments on Bunge's project against the background of the current debate on realism in contemporary analytic philosophy.

  12. Can a virtual supermarket bring realism into the lab? Comparing shopping behavior using virtual and pictorial store representations to behavior in a physical store.

    PubMed

    van Herpen, Erica; van den Broek, Eva; van Trijp, Hans C M; Yu, Tian

    2016-12-01

    Immersive virtual reality techniques present new opportunities for research into consumer behavior. The current study examines whether the increased realism of a virtual store compared to pictorial (2D) stimuli elicits consumer behavior that is more in line with behavior in a physical store. We examine the number, variety, and type of products selected, amount of money spent, and responses to price promotions and shelf display, in three product categories (fruit & vegetables, milk, and biscuits). We find that virtual reality elicits behavior that is more similar to behavior in the physical store compared to the picture condition for the number of products selected (Milk: Mstore = 1.19, Mvirtual = 1.53, Mpictures = 2.58) and amount of money spent (Milk: Mstore = 1.27, Mvirtual = 1.53, Mpictures = 2.60 Euro), and for the selection of products from different areas of the shelf, both vertically (purchases from top shelves, milk and biscuits: Pstore = 21.6%, Pvirtual = 33.4%, Ppictures = 50.0%) and horizontally (purchase from left shelf, biscuits: Pstore = 35.5%, Pvirtual = 53.3%, Ppictures = 66.7%). This indicates that virtual reality can improve realism in responses to shelf allocation. Virtual reality was not able to diminish other differences between lab and physical store: participants bought more products and spent more money (for biscuits and fruit & vegetables), bought more national brands, and responded more strongly to price promotions in both virtual reality and pictorial representations than in the physical store. Implications for the use of virtual reality in studies of consumer food choice behavior as well as for future improvement of virtual reality techniques are discussed.

  13. Mario Bunge's Scientific Realism

    ERIC Educational Resources Information Center

    Cordero, Alberto

    2012-01-01

    This paper presents and comments on Mario Bunge's scientific realism. After a brief introduction in Sects. 1 and 2 outlines Bunge's conception of realism. Focusing on the case of quantum mechanics, Sect. 3 explores how his approach plays out for problematic theories. Section 4 comments on Bunge's project against the background of the current…

  14. Moral realism in nursing.

    PubMed

    Edwards, Steven D

    2014-04-01

    For more than 15 years Professor Per Nortvedt has been arguing the case for moral realism in nursing and the health-care context more generally. His arguments focus on the clinical contexts of nursing and medicine and are supplemented by a series of persuasive examples. Following a description of moral realism, and the kinds of considerations that support it, criticisms of it are developed that seem persuasive. It is argued that our moral responses are explained by our beliefs as opposed to moral realities. In particular, two key arguments presented by Nortvedt are challenged: the so-called argument from convergence and the argument from clinical sensitivity. Both of these key planks in the case for moral realism are rejected, and an alternative 'social conditioning' account briefly sketched, which, it is claimed, has the same explanatory power as Nortvedt's thesis but does not rest on an appeal to independently existing moral properties.

  15. Stereochemistry of the Brivaracetam Diastereoisomers.

    PubMed

    Qiu, Shi; Tehrani, Kourosch Abbaspour; Sergeyev, Sergey; Bultinck, Patrick; Herrebout, Wouter; Mathieu, Benoit

    2016-03-01

    The stereochemistry of all four stereoisomers of brivaracetam was determined using vibrational circular dichroism (VCD) spectroscopy. By comparing experimentally obtained VCD spectra and computationally simulated ones, the absolute configurations can be confidently assigned without prior knowledge of their relative stereochemistry. Neither the corrected mean absolute errors analysis of the nuclear magnetic resonance (NMR) data, nor the matching of experimental and calculated infrared spectra allowed the diastereoisomers to be distinguished. VCD spectroscopy itself suffices to establish the absolute configurations of all diastereoisomers. The relative stereochemistry could also be statistically confirmed by matching experimental and computed NMR spectra using the CP3 algorithm. The combination of VCD and NMR is recommended for molecules bearing more than one chiral center, as the relative configurations obtained from NMR serve as an independent check for those established with VCD. Analysis of the calculated VCD spectra reveals that the localized NH2 scissoring mode at around 1600 cm(-1) is characteristic for intramolecular hydrogen bonding, while the orientation of the ethyl group is reflected by the delocalized modes between 1150 and 1050 cm(-1).

  16. "Old" and "New" Realism in Adolescents' Literature

    ERIC Educational Resources Information Center

    Oliver, Jo Ellen

    1978-01-01

    Discusses whether the "old" realism has matured and the "new" realism (drugs, abortion, and homosexuality) in current books for young people. Compares "Skinny" (in the traditional vein) and "Mom, the Wolf Man and Me" (in terms of new realism). (JM)

  17. Psychology Needs Realism, Not Instrumentalism

    ERIC Educational Resources Information Center

    Haig, Brian D.

    2005-01-01

    In this article, the author presents his comments on "Realism, Instrumentalism, and Scientific Symbiosis: Psychological Theory as a Search for Truth and the Discovery of Solutions" by John T. Cacioppo, Gun R. Semin and Gary G. Berntson. In the original article, the authors recommended the combined use of the philosophies of scientific realism and…

  18. Depressive Realism: Wiser or Quieter?

    ERIC Educational Resources Information Center

    Blanco, Fernando; Matute, Helena; Vadillo, Miguel A.

    2009-01-01

    Depressive realism consists of the lower personal control over uncontrollable events perceived by depressed as compared to nondepressed individuals. In this article, we propose that the realism of depressed individuals is caused not by an increased accuracy in perception, but by their more comprehensive exposure to the actual environmental…

  19. Preoperational Graphic Representation: From Intellectual Realism to Visual Realism in Draw a House-Tree Task.

    ERIC Educational Resources Information Center

    Kalyan-Masih, Violet

    In a pilot study of children's drawings of "a house with a tree behind it," Piagetian sequence (scribbling, fortuitous realism, failed realism, intellectual realism, and visual realism) was tentatively supported. Children's strategies in decentering from intellectual to visual realism were noted. The study reported in this paper was…

  20. What is ontic structural realism?

    NASA Astrophysics Data System (ADS)

    Ainsworth, Peter Mark

    In recent years a doctrine known as ontic structural realism (OSR) has achieved a degree of notoriety, but many people remain confused as to what exactly the doctrine amounts. In this paper three main variants of OSR are defined and discussed: (i) OSR1, which is the view that relations are ontologically primitive but objects and properties are not; (ii) OSR2, which is the view that objects and relations are ontologically primitive but properties are not; (iii) OSR3, which is the view that properties and relations are ontologically primitive but objects are not. Proponents of OSR claim that it is a "naturalistic" metaphysics, arguing that metaphysical views that take objects and/or properties as ontologically primitive are undermined by contemporary physics. In this paper it is argued that OSR1 and OSR2 are themselves undermined by contemporary physics. On the other hand, it is also argued that considerations about the objects of quantum mechanics and general relativity do seem to suggest that we should abandon some of our "common-sense" metaphysical intuitions, and that OSR3 is one of the metaphysical views that is compatible with what these theories seem to tell us about fundamental ontology.

  1. Structural realism versus deployment realism: A comparative evaluation.

    PubMed

    Lyons, Timothy D

    2016-10-01

    In this paper I challenge and adjudicate between the two positions that have come to prominence in the scientific realism debate: deployment realism and structural realism. I discuss a set of cases from the history of celestial mechanics, including some of the most important successes in the history of science. To the surprise of the deployment realist, these are novel predictive successes toward which theoretical constituents that are now seen to be patently false were genuinely deployed. Exploring the implications for structural realism, I show that the need to accommodate these cases forces our notion of "structure" toward a dramatic depletion of logical content, threatening to render it explanatorily vacuous: the better structuralism fares against these historical examples, in terms of retention, the worse it fares in content and explanatory strength. I conclude by considering recent restrictions that serve to make "structure" more specific. I show however that these refinements will not suffice: the better structuralism fares in specificity and explanatory strength, the worse it fares against history. In light of these case studies, both deployment realism and structural realism are significantly threatened by the very historical challenge they were introduced to answer.

  2. Local realism of macroscopic correlations.

    PubMed

    Ramanathan, R; Paterek, T; Kay, A; Kurzyński, P; Kaszlikowski, D

    2011-08-05

    We identify conditions under which correlations resulting from quantum measurements performed on macroscopic systems (systems composed of a number of particles of the order of the Avogadro number) can be described by local realism. We argue that the emergence of local realism at the macroscopic level is caused by an interplay between the monogamous nature of quantum correlations and the fact that macroscopic measurements do not reveal properties of individual particles.

  3. Local Realism of Macroscopic Correlations

    NASA Astrophysics Data System (ADS)

    Ramanathan, R.; Paterek, T.; Kay, A.; Kurzyński, P.; Kaszlikowski, D.

    2011-08-01

    We identify conditions under which correlations resulting from quantum measurements performed on macroscopic systems (systems composed of a number of particles of the order of the Avogadro number) can be described by local realism. We argue that the emergence of local realism at the macroscopic level is caused by an interplay between the monogamous nature of quantum correlations and the fact that macroscopic measurements do not reveal properties of individual particles.

  4. Orbital State Uncertainty Realism

    NASA Astrophysics Data System (ADS)

    Horwood, J.; Poore, A. B.

    2012-09-01

    Fundamental to the success of the space situational awareness (SSA) mission is the rigorous inclusion of uncertainty in the space surveillance network. The *proper characterization of uncertainty* in the orbital state of a space object is a common requirement to many SSA functions including tracking and data association, resolution of uncorrelated tracks (UCTs), conjunction analysis and probability of collision, sensor resource management, and anomaly detection. While tracking environments, such as air and missile defense, make extensive use of Gaussian and local linearity assumptions within algorithms for uncertainty management, space surveillance is inherently different due to long time gaps between updates, high misdetection rates, nonlinear and non-conservative dynamics, and non-Gaussian phenomena. The latter implies that "covariance realism" is not always sufficient. SSA also requires "uncertainty realism"; the proper characterization of both the state and covariance and all non-zero higher-order cumulants. In other words, a proper characterization of a space object's full state *probability density function (PDF)* is required. In order to provide a more statistically rigorous treatment of uncertainty in the space surveillance tracking environment and to better support the aforementioned SSA functions, a new class of multivariate PDFs are formulated which more accurately characterize the uncertainty of a space object's state or orbit. The new distribution contains a parameter set controlling the higher-order cumulants which gives the level sets a distinctive "banana" or "boomerang" shape and degenerates to a Gaussian in a suitable limit. Using the new class of PDFs within the general Bayesian nonlinear filter, the resulting filter prediction step (i.e., uncertainty propagation) is shown to have the *same computational cost as the traditional unscented Kalman filter* with the former able to maintain a proper characterization of the uncertainty for up to *ten

  5. Introducing Stereochemistry to Non-science Majors

    NASA Astrophysics Data System (ADS)

    Luján-Upton, Hannia

    2001-04-01

    Stereochemistry is often a difficult topic for both science and non-science majors to learn. The topics covered in most undergraduate textbooks, although fundamental, seem very abstract to most students. This manuscript describes two simple exercises that can be used to introduce concepts associated with stereochemistry such as "sameness", superimposability, chirality, enantiomers, optical activity, polarimetry, and racemic mixtures. One exercise compares chirality in hands with the achiral nature of two textbooks. The other exercise involves a murder mystery, the solution of which hinges upon understanding the concept of optical activity, specifically in natural products such as toxins from poisonous mushrooms.

  6. Earth Observing System Covariance Realism

    NASA Technical Reports Server (NTRS)

    Zaidi, Waqar H.; Hejduk, Matthew D.

    2016-01-01

    The purpose of covariance realism is to properly size a primary object's covariance in order to add validity to the calculation of the probability of collision. The covariance realism technique in this paper consists of three parts: collection/calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics. An empirical cumulative distribution function (ECDF) Goodness-of-Fit (GOF) method is employed to determine if a covariance is properly sized by comparing the empirical distribution of Mahalanobis distance calculations to the hypothesized parent 3-DoF chi-squared distribution. To realistically size a covariance for collision probability calculations, this study uses a state noise compensation algorithm that adds process noise to the definitive epoch covariance to account for uncertainty in the force model. Process noise is added until the GOF tests pass a group significance level threshold. The results of this study indicate that when outliers attributed to persistently high or extreme levels of solar activity are removed, the aforementioned covariance realism compensation method produces a tuned covariance with up to 80 to 90% of the covariance propagation timespan passing (against a 60% minimum passing threshold) the GOF tests-a quite satisfactory and useful result.

  7. [Depressive realism: happiness or objectivity].

    PubMed

    Birinci, Fatih; Dirik, Gülay

    2010-01-01

    Realism is described as objective evaluations and judgments about the world; however, some research indicates that judgments made by "normal" people include a self-favored, positive bias in the perception of reality. Additionally, some studies report that compared to normal people, such cognitive distortions are less likely among depressive people. These findings gave rise to the depressive realism hypothesis. While results of several studies verify the notion that depressive people evaluate reality more objectively, other studies fail to support this hypothesis. Several causes for these inconsistent findings have been proposed, which can be characterized under 3 headings. One proposed explanation suggests that what is accepted as "realistic" in these studies is not quite objective and is in fact ambiguous. According to another perspective, the term "depressive" used in these studies is inconsistent with the criteria of scientific diagnostic methods. Another suggests that the research results can only be obtained under the specific experimental conditions. General negativity and limited processing are popular approaches used for explaining the depressive realism hypothesis. Nowadays, the debate over this hypothesis continues. The present review focuses on frequently cited research related to depressive realism and discusses the findings.

  8. Absolute stereochemistry of altersolanol A and alterporriols.

    PubMed

    Kanamaru, Saki; Honma, Miho; Murakami, Takanori; Tsushima, Taro; Kudo, Shinji; Tanaka, Kazuaki; Nihei, Ken-Ichi; Nehira, Tatsuo; Hashimoto, Masaru

    2012-02-01

    The absolute stereochemistry of altersolanol A (1) was established by observing a positive exciton couplet in the circular dichroism (CD) spectrum of the C3,C4-O-bis(2-naphthoyl) derivative 10 and by chemical correlations with known compound 8. Before the discussion, the relative stereochemistry of 1 was confirmed by X-ray crystallographic analysis. The shielding effect at C7'-OMe group by C1-O-benzoylation established the relative stereochemical relationship between the C8-C8' axial bonding and the C1-C4/C1'-C4' polyol moieties of alterporriols E (3), an atropisomer of the C8-C8' dimer of 1. As 3 could be obtained by dimerization of 1 in vitro, the absolute configuration of its central chirality elements (C1-C4) must be identical to those of 1. Spectral comparison between the experimental and theoretical CD spectra supported the above conclusion. Axial stereochemistry of novel C4-O-deoxy dimeric derivatives, alterporriols F (4) and G (5), were also revealed by comparison of their CD spectra to those of 2 and 3.

  9. The Stereochemistry of Biochemical Molecules: A Subject to Revisit

    ERIC Educational Resources Information Center

    Centelles, Josep J.; Imperial, Santiago

    2005-01-01

    Although Fischer's convention for stereoisomers is useful for simple molecules, the stereochemistry of complex biochemical molecules is often poorly indicated in textbooks. This article reports on errors in stereochemistry of complex hydrosoluble vitamin B12 molecule. Twenty-five popular biochemistry textbooks were examined for their treatment of…

  10. Young Adult Realism: Conventions, Narrators, and Readers.

    ERIC Educational Resources Information Center

    Ross, Catherine Sheldrick

    1985-01-01

    Examination of a subset of books popular with young adults--problem novels or young adult realism--is based on deductions concerning nature of reading response that text invites. Young adult realism as formula of popular culture, changes in conventions, narrators and narratees, and identification and distance are discussed. (34 references) (EJS)

  11. Interrogating the "Real" in Young Adult Realism.

    ERIC Educational Resources Information Center

    Brown, Joanne

    1999-01-01

    Discusses the complexities of defining "realism," examining how the term fueled many discussions in the author's college adolescent literature course. Looks at how writers and critics define the term. Shares alternatives to circuitous arguments about the relative realism of a text that helps students explore texts in effective ways that can lead…

  12. The Universities and the Challenge of Realism

    ERIC Educational Resources Information Center

    Evans, Mary

    2010-01-01

    Universities are often enjoined to "get" with the "real world". In this article, Mary Evans gives an account of interpretations of literary realism in order to consider the "coercive realism" of the contemporary university. The prevailing assumptions that universities must contribute to the "real" world are…

  13. Ethical Realism: A Guide to Action?

    ERIC Educational Resources Information Center

    Matkin, Gary

    2008-01-01

    This article presents the author's response to Gary Miller's essay entitled "Ethical Realism and Continuing Education." In his essay, Dr. Miller has provided a valuable opportunity to reflect on the practice of continuing education (CE) leadership. Dr. Miller reviews six principles that are encapsulated in the concept of ethical realism, but are…

  14. Nosology, ontology and promiscuous realism.

    PubMed

    Binney, Nicholas

    2015-06-01

    Medics may consider worrying about their metaphysics and ontology to be a waste of time. I will argue here that this is not the case. Promiscuous realism is a metaphysical position which holds that multiple, equally valid, classification schemes should be applied to objects (such as patients) to capture different aspects of their complex and heterogeneous nature. As medics at the bedside may need to capture different aspects of their patients' problems, they may need to use multiple classification schemes (multiple nosologies), and thus consider adopting a different metaphysics to the one commonly in use.

  15. Stereochemistry in subcomponent self-assembly.

    PubMed

    Castilla, Ana M; Ramsay, William J; Nitschke, Jonathan R

    2014-07-15

    CONSPECTUS: As Pasteur noted more than 150 years ago, asymmetry exists in matter at all organization levels. Biopolymers such as proteins or DNA adopt one-handed conformations, as a result of the chirality of their constituent building blocks. Even at the level of elementary particles, asymmetry exists due to parity violation in the weak nuclear force. While the origin of homochirality in living systems remains obscure, as does the possibility of its connection with broken symmetries at larger or smaller length scales, its centrality to biomolecular structure is clear: the single-handed forms of bio(macro)molecules interlock in ways that depend upon their handednesses. Dynamic artificial systems, such as helical polymers and other supramolecular structures, have provided a means to study the mechanisms of transmission and amplification of stereochemical information, which are key processes to understand in the context of the origins and functions of biological homochirality. Control over stereochemical information transfer in self-assembled systems will also be crucial for the development of new applications in chiral recognition and separation, asymmetric catalysis, and molecular devices. In this Account, we explore different aspects of stereochemistry encountered during the use of subcomponent self-assembly, whereby complex structures are prepared through the simultaneous formation of dynamic coordinative (N → metal) and covalent (N═C) bonds. This technique provides a useful method to study stereochemical information transfer processes within metal-organic assemblies, which may contain different combinations of fixed (carbon) and labile (metal) stereocenters. We start by discussing how simple subcomponents with fixed stereogenic centers can be incorporated in the organic ligands of mononuclear coordination complexes and communicate stereochemical information to the metal center, resulting in diastereomeric enrichment. Enantiopure subcomponents were then

  16. Hardy's test for local realism

    NASA Astrophysics Data System (ADS)

    Nguyen, Quynh; Dregli, Aurelio

    2014-03-01

    We demonstrated the violation of Bell inequality using entangled photons produced by spontaneous parametric down-conversion. The experiment is based on a local realism test originally proposed by Lucien Hardy. Polarized entangled photons is produced in down-conversion through a pair of beta barium borate crystals. Polarization is adjusted by half wave plates and quartz plates. Single photons travel down two separate paths, each pass through a half-wave plate and a broad band polarizing beam splitter. Light from the beam splitter is collected by lens and focused into optic fibers that direct light into a single photon counting module. Coincidence counting is done using time-to-amplitude converter/single-channel-analyzer units. The probabilities in Bell-Clauser-Horne inequality is calculated by the ratio of the measured coincidence counts on the transmitted laser beams to the total number of coincidence. The counting is done by a LabVIEW program. We find the data to violate local realism by 30 standard deviation. The experiment is based on straight forward quantum mechanical calculations and experimental techniques more accessible to undergraduate students than other methods of testing Bell inequalities.

  17. Familiar faces rendered strange: Why inconsistent realism drives characters into the uncanny valley

    PubMed Central

    Chattopadhyay, Debaleena; MacDorman, Karl F.

    2016-01-01

    Computer-modeled characters resembling real people sometimes elicit cold, eerie feelings. This effect, called the uncanny valley, has been attributed to uncertainty about whether the character is human or living or real. Uncertainty, however, neither explains why anthropomorphic characters lie in the uncanny valley nor their characteristic eeriness. We propose that realism inconsistency causes anthropomorphic characters to appear unfamiliar, despite their physical similarity to real people, owing to perceptual narrowing. We further propose that their unfamiliar, fake appearance elicits cold, eerie feelings, motivating threat avoidance. In our experiment, 365 participants categorized and rated objects, animals, and humans whose realism was manipulated along consistency-reduced and control transitions. These data were used to quantify a Bayesian model of categorical perception. In hypothesis testing, we found reducing realism consistency did not make objects appear less familiar, but only animals and humans, thereby eliciting cold, eerie feelings. Next, structural equation models elucidated the relation among realism inconsistency (measured objectively in a two-dimensional Morlet wavelet domain inspired by the primary visual cortex), realism, familiarity, eeriness, and warmth. The fact that reducing realism consistency only elicited cold, eerie feelings toward anthropomorphic characters, and only when it lessened familiarity, indicates the role of perceptual narrowing in the uncanny valley. PMID:27611063

  18. Familiar faces rendered strange: Why inconsistent realism drives characters into the uncanny valley.

    PubMed

    Chattopadhyay, Debaleena; MacDorman, Karl F

    2016-09-01

    Computer-modeled characters resembling real people sometimes elicit cold, eerie feelings. This effect, called the uncanny valley, has been attributed to uncertainty about whether the character is human or living or real. Uncertainty, however, neither explains why anthropomorphic characters lie in the uncanny valley nor their characteristic eeriness. We propose that realism inconsistency causes anthropomorphic characters to appear unfamiliar, despite their physical similarity to real people, owing to perceptual narrowing. We further propose that their unfamiliar, fake appearance elicits cold, eerie feelings, motivating threat avoidance. In our experiment, 365 participants categorized and rated objects, animals, and humans whose realism was manipulated along consistency-reduced and control transitions. These data were used to quantify a Bayesian model of categorical perception. In hypothesis testing, we found reducing realism consistency did not make objects appear less familiar, but only animals and humans, thereby eliciting cold, eerie feelings. Next, structural equation models elucidated the relation among realism inconsistency (measured objectively in a two-dimensional Morlet wavelet domain inspired by the primary visual cortex), realism, familiarity, eeriness, and warmth. The fact that reducing realism consistency only elicited cold, eerie feelings toward anthropomorphic characters, and only when it lessened familiarity, indicates the role of perceptual narrowing in the uncanny valley.

  19. Critical realism in nursing: an emerging approach.

    PubMed

    Schiller, Catharine J

    2016-04-01

    Critical realism, a philosophical framework originally developed by Roy Bhaskar in the 1970s, represents a relatively new approach to research generally and to nursing research in particular. This article explores the ontological and epistemological tenets of critical realism and examines the application of critical realist principles to nursing research and practice through a review of the literature. It is evident that few published nursing research studies have, as of yet, utilized critical realism as their paradigm of choice. Both the strengths and limitations of the presentation and use of critical realism in these studies are discussed in this article. Given the varying degrees of success of the authors in explicating critical realism as a philosophical framework, the value of critical realism to the research study, and the ways in which usage of the critical realist framework influenced development of the study and interpretation of findings, it is evident that the quality of future publications espousing the use of critical realism must continue to be strengthened significantly.

  20. Realism and Impartiality: Making Sustainability Effective in Decision-Making.

    PubMed

    Bastons, Miquel; Armengou, Jaume

    2016-11-24

    There is both individual and collective widespread concern in society about the impact of human activity and the effects of our decisions on the physical and social environment. This concern is included within the idea of sustainability. The meaning of the concept is still ambiguous and its practical effectiveness disputed. Like many other authors, this article uses as a starting point the definition proposed by the World Commission on Environment and Development (Our common future, Oxford University Press, Oxford, 1987), considering it to be a proposal for changing the assessment of the effects of decisions, from at least two perspectives: (1) what effects we should consider and (2) how we should assess them. Based on this double perspective, sustainability is explored as a method for decision-making which both expands the assessment of the consequences, and also provides an objective criterion for such assessment. It will be argued that the idea of sustainability, seen from this perspective, brings to decision-making two qualities which had been partially lost: realism and impartiality. In turn, the criteria for realism and impartiality in decision-making can be used to identify the limitations of some partial approaches to sustainability, which suffer from insufficient realism (emotional altruism), insufficient impartiality (tactical altruism) or both phenomena at once (egoism). The article concludes by demonstrating how realism and impartiality provide the basis for a new form of sustainable decision-making (ethical sustainability), which is dependent on the development of two moral virtues, prudence and benevolence, and which brings practical effectiveness and ethical sense to the concept of sustainability.

  1. Depressive realism: a meta-analytic review.

    PubMed

    Moore, Michael T; Fresco, David M

    2012-08-01

    The current investigation represents the first meta-analysis of the depressive realism literature. A search of this literature revealed 75 relevant studies representing 7305 participants from across the US and Canada, as well as from England, Spain, and Israel. Results generally indicated a small overall depressive realism effect (Cohen's d=-.07). Overall, however, both dysphoric/depressed individuals (d=.14) and nondysphoric/nondepressed individuals evidenced a substantial positive bias (d=.29), with this bias being larger in nondysphoric/nondepressed individuals. Examination of potential moderator variables indicated that studies lacking an objective standard of reality (d=-.15 versus -.03, for studies possessing such a standard) and that utilize self-report measures to measure symptoms of depression (d=.16 versus -.04, for studies which utilize structured interviews) were more likely to find depressive realism effects. Methodological paradigm was also found to influence whether results consistent with depressive realism were found (d's ranged from -.09 to .14).

  2. Social acceptance of comparative optimism and realism.

    PubMed

    Milhabet, I; Verlhiac, J F

    2011-10-01

    Studies of optimism and realism (the accuracy of people's outlook on the future) seek to understand the respective effects of these elements on social approbation. Two experiments examined how comparative optimism (vs. pessimism) and realism (vs. unrealism) interacted to influence the targets' social acceptance based on their perceptions about the future. The results showed that realism, or accuracy of prediction, increased the positive social effects of a comparatively optimistic outlook on the future. In contrast, targets who exhibited comparative pessimism were more socially acceptable when their predictions were unrealistic rather than realistic. This phenomenon was examined by also considering the polarity of the events about which judgments were expressed. These results contribute to the body of research about the relationship between optimism and pessimism and the relationship between optimism and realism.

  3. The methodological defense of realism scrutinized.

    PubMed

    Wray, K Brad

    2015-12-01

    I revisit an older defense of scientific realism, the methodological defense, a defense developed by both Popper and Feyerabend. The methodological defense of realism concerns the attitude of scientists, not philosophers of science. The methodological defense is as follows: a commitment to realism leads scientists to pursue the truth, which in turn is apt to put them in a better position to get at the truth. In contrast, anti-realists lack the tenacity required to develop a theory to its fullest. As a consequence, they are less likely to get at the truth. My aim is to show that the methodological defense is flawed. I argue that a commitment to realism does not always benefit science, and that there is reason to believe that a research community with both realists and anti-realists in it may be better suited to advancing science. A case study of the Copernican Revolution in astronomy supports this claim.

  4. Relative stereochemistry of the A ring of plant bile pigments

    SciTech Connect

    Schoenleber, R.W.; Kim, Y.; Rapoport, H.

    1984-05-02

    The synthesis and characterization, including the stereochemistry, of a series of 3,4-dihydropyrromethenones and 2,3-dihydrodioxobilins are described. High-resolution /sup 1/H NMR spectral analysis allows the determination of the A ring coupling constants for a series of cis and trans model compounds. From these data and correlations, the relative stereochemistry in the A ring of phycocyanin and similar bile pigment structures can be concluded.

  5. Cosmology and the Demise of Color Realism

    NASA Astrophysics Data System (ADS)

    Hockey, Thomas

    2011-04-01

    Scientific realism is a bulwark of modern metaphysics, especially entity realism. Scientists expect there to be real objects in nature that may be enumerated and measured using objective properties. (Rest mass is an example.) Is color one of these properties? The question, "What is the color of the Universe?" unexpectedly leads to the conclusion that it is not. Astronomers use the concept of color at their ontological peril.

  6. Investigating Realism in the Arts: Can Elements of Realism Be Identified in "Enter Achilles" (Lloyd Newson)?

    ERIC Educational Resources Information Center

    Wall, Mellina

    2006-01-01

    This paper investigates realism both as an artistic attitude within the arts, and more specifically in relation to Lloyd Newson's "Enter Achilles". There is initially a discussion of realism, focusing on the theories of Lukacs and Brecht in relation to art, and an attempt to relate these ideas more specifically to dance. Discussion of "Enter…

  7. Realism Assessment of Sonic Boom Simulators

    NASA Technical Reports Server (NTRS)

    Sullivan, Brenda M.; Davies, Patrica; Hodgdon, Kthleen K.; Salamone, Joseph A., III; Pilon, Anthony

    2008-01-01

    Developments in small supersonic aircraft design are predicted to result in low-intensity sonic booms. Booms generated by current aircraft are similar to those that led to the ban on commercial supersonic fli ght over the US, so are unsuitable for parametric studies of psychoac oustic response to low-intensity booms. Therefore, simulators have be en used to study the impact of predicted low-intensity sonic booms. H owever, simulators have been criticized because, when simulating conv entional-level booms, the sounds were observed to be unrealistic by p eople experienced in listening to sonic booms. Thus, two studies were conducted to measure the perceived realism of three sonic boom simul ators. Experienced listeners rated the realism of conventional sonic boom signatures when played in these simulators. The effects on percei ved realism of factors such as duration of post-boom noise, exclusion of very low frequency components, inclusion of ground reflections, a nd type of simulator were examined. Duration of post-boom noise was f ound to have a strong effect on perceived realism, while type of simu lator had a weak effect. It was determined that post-boom noise had t o be at least 1.5 seconds long for the sound to be rated very realist ic. Loudness level did not affect realism for the range of sounds pla yed in the tests (80-93 dB ASEL).

  8. Realism, functions, and the a priori: Ernst Cassirer's philosophy of science.

    PubMed

    Heis, Jeremy

    2014-12-01

    This paper presents the main ideas of Cassirer's general philosophy of science, focusing on the two aspects of his thought that--in addition to being the most central ideas in his philosophy of science--have received the most attention from contemporary philosophers of science: his theory of the a priori aspects of physical theory, and his relation to scientific realism.

  9. The sad truth about depressive realism.

    PubMed

    Allan, Lorraine G; Siegel, Shepard; Hannah, Samuel

    2007-03-01

    In one form of a contingency judgement task individuals must judge the relationship between an action and an outcome. There are reports that depressed individuals are more accurate than are non-depressed individuals in this task. In particular, nondepressed individuals are influenced by manipulations that affect the salience of the outcome, especially outcome probability. They overestimate a contingency if the probability of an outcome is high--the "outcome-density effect". In contrast, depressed individuals display little or no outcome-density effect. This apparent knack for depressives not to be misled by outcome density in their contingency judgements has been termed "depressive realism", and the absence of an outcome-density effect has led to the characterization of depressives as "sadder but wiser". We present a critical summary of the depressive realism literature and provide a novel interpretation of the phenomenon. We suggest that depressive realism may be understood from a psychophysical analysis of contingency judgements.

  10. Must Metaethical Realism Make a Semantic Claim?

    PubMed

    Kahane, Guy

    2013-02-01

    Mackie drew attention to the distinct semantic and metaphysical claims made by meta ethical realists, arguing that although our evaluative discourse is cognitive and objective, there are no objective evaluative facts. This distinction, however, also opens up a reverse possibility: that our evaluative discourse is antirealist, yet objective values do exist. I suggest that this seemingly far-fetched possibility merits serious attention; realism seems com mitted to its intelligibility, and, despite appearances, it isn't incoherent, ineffable, inherently implausible or impossible to defend. I argue that reflection on this possibility should lead us to revise our understanding of the debate between realists and antirealists. It is not only that the realist's semantic claim is insufficient for realism to be true, as Mackie argued; it's not even necessary. Robust metaethical realism is best understood as making a purely metaphysical claim. It is thus not enough for antirealists to show that our discourse is antirealist. They must directly attack the realist's metaphysical claim.

  11. New Tests of Macroscopic Local Realism

    NASA Astrophysics Data System (ADS)

    Reid, M. D.

    We show that quantum mechanics predicts an Einstein-Podolsky-Rosen paradox (EPR), and also a contradiction with local hidden variable theories, for photon number measurements which have limited resolving power, to the point of imposing an uncertainty in the photon number result which is macroscopic in absolute terms. We show how this can be interpreted as a failure of a new, very strong premise, called macroscopic local realism. We link this premise to the Schrodinger-cat paradox. Our proposed experiments ensure all fields incident on each measurement apparatus are macroscopic. We show that an alternative measurement scheme corresponds to balanced homodyne detection of quadrature phase amplitudes. The implication is that where either EPR correlations or failure of local realism is predicted for quadrature phase amplitude measurements, one can potentially perform a modified experiment which would lead to conclusions about the much stronger premise of macroscopic local realism.

  12. Metacognitive Realism: A Cognitive Style or a Learning Strategy?

    ERIC Educational Resources Information Center

    Jans, Veronique; Leclercq, Dieudonne

    1997-01-01

    Identifies metacognitive realism as the accurate assessment by a learner of their knowledge on a subject. Considers whether realism in metacognition is a stable trait, and possible influences. Briefly reviews the literature and experimental evidence and concludes that metacognitive realism is both style and strategy. (MJP)

  13. 48 CFR 1515.404-475 - Cost realism.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Cost realism. 1515.404-475... METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1515.404-475 Cost realism. The EPA structured approach is not required when the contracting officer is evaluating cost realism in a...

  14. 48 CFR 1515.404-475 - Cost realism.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Cost realism. 1515.404-475... METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1515.404-475 Cost realism. The EPA structured approach is not required when the contracting officer is evaluating cost realism in a...

  15. 48 CFR 1515.404-475 - Cost realism.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Cost realism. 1515.404-475... METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1515.404-475 Cost realism. The EPA structured approach is not required when the contracting officer is evaluating cost realism in a...

  16. 48 CFR 1515.404-475 - Cost realism.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Cost realism. 1515.404-475... METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1515.404-475 Cost realism. The EPA structured approach is not required when the contracting officer is evaluating cost realism in a...

  17. Critical Realism and Statistical Methods--A Response to Nash

    ERIC Educational Resources Information Center

    Scott, David

    2007-01-01

    This article offers a defence of critical realism in the face of objections Nash (2005) makes to it in a recent edition of this journal. It is argued that critical and scientific realisms are closely related and that both are opposed to statistical positivism. However, the suggestion is made that scientific realism retains (from statistical…

  18. 48 CFR 1515.404-475 - Cost realism.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Cost realism. 1515.404-475... METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1515.404-475 Cost realism. The EPA structured approach is not required when the contracting officer is evaluating cost realism in a...

  19. Queer Genes: Realism, Sexuality and Science

    PubMed Central

    Griffiths, David Andrew

    2016-01-01

    What are ‘gay genes’ and are they real? This article looks at key research into these hypothesized gay genes, made possible, in part, by the Human Genome Project. I argue that the complexity of both genetics and human sexuality demands a truly critical approach: one that takes into account feminist epistemologies of science and queer approaches to the body, while putting into conversation resources from agential realism and critical realism. This approach is able to maintain the agential complexity of genetic materiality, while also critically challenging the seemingly stable relationships between sex, gender and sexuality. PMID:28058037

  20. Queer Genes: Realism, Sexuality and Science.

    PubMed

    Griffiths, David Andrew

    2016-10-19

    What are 'gay genes' and are they real? This article looks at key research into these hypothesized gay genes, made possible, in part, by the Human Genome Project. I argue that the complexity of both genetics and human sexuality demands a truly critical approach: one that takes into account feminist epistemologies of science and queer approaches to the body, while putting into conversation resources from agential realism and critical realism. This approach is able to maintain the agential complexity of genetic materiality, while also critically challenging the seemingly stable relationships between sex, gender and sexuality.

  1. Aesthetic Description and Realism in Art Education.

    ERIC Educational Resources Information Center

    Brown, Neil C. M.

    1989-01-01

    Looks at the usefulness of a stable realism for questions related to the description and understanding of art works. Explores two theories which may resolve the antagonism between representational meanings and their assertion as true properties of the work: (1) Wiggin's concept of authentic effect; and (2) Petit's theory of rectification and…

  2. Inspirational Realism: Chesley Bonestell and Astronomical Art

    NASA Astrophysics Data System (ADS)

    Perkowitz, S.

    2013-04-01

    At the very beginning of the space age, some sixty years ago, the American artist and illustrator Chesley Bonestell portrayed planets, stars, and spacecraft with stunning, near-photographic realism. Collaborating with experts like rocket pioneer Wernher von Braun, Bonestell's renditions combined the best scientific and engineering knowledge of the time, and scientific exactness, with artistic imagination.

  3. Locality and realism in contextual theories

    SciTech Connect

    Hoekzema, D.

    1987-08-01

    Two types of contextual theories are distinguished and shown to be related. For theories of each type a criterion of locality is formulated which is weaker than the classical requirement of separability at spacelike intervals. The relations between the concepts of locality, realism, and ontic chance are discussed.

  4. Testing nonlocal realism with entangled coherent states

    SciTech Connect

    Paternostro, Mauro; Jeong, Hyunseok

    2010-03-15

    We investigate the violation of nonlocal realism using entangled coherent states (ECSs) under nonlinear operations and homodyne measurements. We address recently proposed Leggett-type inequalities, including a class of optimized incompatibility inequalities proposed by Branciard et al. [Nature Phys. 4, 681 (2008)], and thoroughly assess the effects of detection inefficiency.

  5. Violation of local realism versus detection efficiency

    SciTech Connect

    Massar, Serge; Pironio, Stefano

    2003-12-01

    We put bounds on the minimum detection efficiency necessary to violate local realism in Bell experiments. These bounds depend on simple parameters like the number of measurement settings or the dimensionality of the entangled quantum state. We derive them by constructing explicit local hidden variable models which reproduce the quantum correlations for sufficiently small detectors efficiency.

  6. Realism and constructivism in social perception.

    PubMed

    Kihlstrom, John F

    2017-01-01

    Jussim's critique of social psychology's embrace of error and bias is needed and often persuasive. In opting for perceptual realism over social constructivism, however, he seems to ignore a third choice - a cognitive constructivism which has a long and distinguished history in the study of nonsocial perception, and which enables us to understand both accuracy and error.

  7. An Engaging Illustration of the Physical Differences among Menthol Stereoisomers

    ERIC Educational Resources Information Center

    Treadwell, Edward M.; Black, T. Howard

    2005-01-01

    An experiment illustrating stereochemical principles, like different physical properties in achiral environments, assignment of absolute stereochemistry, and the stereoisomeric relationships to differences in absolute stereochemistry is devised. A demonstration of how enantiomers have the same physical properties until placed in chiral…

  8. An Adventure in Stereochemistry: Alice in Mirror Image Land

    ERIC Educational Resources Information Center

    Dinan, Frank J.; Yee, Gordon T.

    2004-01-01

    This case is based on an article that considered the problems that would arise if a person were to cross over into a mirror-image environment (Yee 2002). Some of the stereochemistry problems posed in that article are woven into this case study. (Contains 8 figures.)

  9. Dynamic Stereochemistry: A Simple Approach to Delineating Relative Configuration

    ERIC Educational Resources Information Center

    Mandal, Dipak K.

    2007-01-01

    A simple approach for delineating the stereochemistry of the products relative to that of the reactants in reactions involving stereogenic centers is addressed. The reaction at the tetrahedral center involves the cleavage of a bond to one of the ligands in the reactant and the resulting new ligand in the product is labeled by affixing prime to the…

  10. The ontology of quantum field theory: Structural realism vindicated?

    PubMed

    Glick, David

    2016-10-01

    In this paper I elicit a prediction from structural realism and compare it, not to a historical case, but to a contemporary scientific theory. If structural realism is correct, then we should expect physics to develop theories that fail to provide an ontology of the sort sought by traditional realists. If structure alone is responsible for instrumental success, we should expect surplus ontology to be eliminated. Quantum field theory (QFT) provides the framework for some of the best confirmed theories in science, but debates over its ontology are vexed. Rather than taking a stand on these matters, the structural realist can embrace QFT as an example of just the kind of theory SR should lead us to expect. Yet, it is not clear that QFT meets the structuralist's positive expectation by providing a structure for the world. In particular, the problem of unitarily inequivalent representations threatens to undermine the possibility of QFT providing a unique structure for the world. In response to this problem, I suggest that the structuralist should endorse pluralism about structure.

  11. Prediction of Stereochemistry using Q2MM

    PubMed Central

    2016-01-01

    screens on a range of transition metal-catalyzed reactions that are important from both an industrial and an academic perspective. In this Account, we provide an overview of the continued improvement of the prediction of stereochemistry using Q2MM-derived TSFFs using four examples from different stages of development: (i) Pd-catalyzed allylation, (ii) OsO4-catalyzed asymmetric dihydroxylation (AD) of alkenes, (iii) Rh-catalyzed hydrogenation of enamides, and (iv) Ru-catalyzed hydrogenation of ketones. In the current form, correlation coefficients of 0.8–0.9 between calculated and experimental ee values are typical for a wide range of substrate–ligand combinations, and suitable ligands can be predicted for a given substrate with ∼80% accuracy. Although the generation of a TSFF requires an initial effort and will therefore be most useful for widely used reactions that require frequent screening campaigns, the method allows for a rapid virtual screen of large ligand libraries to focus experimental efforts on the most promising substrate–ligand combinations. PMID:27064579

  12. Prediction of Stereochemistry using Q2MM.

    PubMed

    Hansen, Eric; Rosales, Anthony R; Tutkowski, Brandon; Norrby, Per-Ola; Wiest, Olaf

    2016-05-17

    transition metal-catalyzed reactions that are important from both an industrial and an academic perspective. In this Account, we provide an overview of the continued improvement of the prediction of stereochemistry using Q2MM-derived TSFFs using four examples from different stages of development: (i) Pd-catalyzed allylation, (ii) OsO4-catalyzed asymmetric dihydroxylation (AD) of alkenes, (iii) Rh-catalyzed hydrogenation of enamides, and (iv) Ru-catalyzed hydrogenation of ketones. In the current form, correlation coefficients of 0.8-0.9 between calculated and experimental ee values are typical for a wide range of substrate-ligand combinations, and suitable ligands can be predicted for a given substrate with ∼80% accuracy. Although the generation of a TSFF requires an initial effort and will therefore be most useful for widely used reactions that require frequent screening campaigns, the method allows for a rapid virtual screen of large ligand libraries to focus experimental efforts on the most promising substrate-ligand combinations.

  13. Applying ontological realism to medically unexplained syndromes.

    PubMed

    Doing-Harris, Kristina; Meystre, Stephane M; Samore, Matthew; Ceusters, Werner

    2013-01-01

    The past decade has witnessed an increased interest in what are called "medically unexplained syndromes" (MUS). We address the question of whether structuring the domain knowledge for MUS can be achieved by applying the principles of Ontological Realism in light of criticisms about their usefulness in areas where science has not yet led to insights univocally endorsed by the relevant communities. We analyzed whether the different perspectives held by MUS researchers can be represented without taking any particular stance and whether existing ontologies based on Ontological Realism can be further built upon. We did not find refutation of the applicability of the principles. We found the Ontology of General Medical Science and Information Artifact Ontology to provide useful frameworks for analyzing certain MUS controversies, although leaving other questions open.

  14. Increasing Realism in Virtual Marksmanship Simulators

    DTIC Science & Technology

    2012-12-01

    2) improving or enhancing a factor, such as graphics quality , will have a positive effect on a participants objective score and/or their subjective...realism of virtual marksmanship simulators, and (2) improving or enhancing a factor, such as graphics quality , will have a positive effect on a...enhance the overall simulation? H02: Improving or enhancing a factor, such as graphics quality , will have no discernible effect on a participant’s

  15. Perceived game realism: a test of three alternative models.

    PubMed

    Ribbens, Wannes

    2013-01-01

    Perceived realism is considered a key concept in explaining the mental processing of media messages and the societal impact of media. Despite its importance, little is known about its conceptualization and dimensional structure, especially with regard to digital games. The aim of this study was to test a six-factor model of perceived game realism comprised of simulational realism, freedom of choice, perceptual pervasiveness, social realism, authenticity, and character involvement and to assess it against an alternative single- and five-factor model. Data were collected from 380 male digital game users who judged the realism of the first-person shooter Half-Life 2 based upon their previous experience with the game. Confirmatory factor analysis was applied to investigate which model fits the data best. The results support the six-factor model over the single- and five-factor solutions. The study contributes to our knowledge of perceived game realism by further developing its conceptualization and measurement.

  16. Violation of smooth observable macroscopic realism in a harmonic oscillator.

    PubMed

    Leshem, Amir; Gat, Omri

    2009-08-14

    We study the emergence of macrorealism in a harmonic oscillator subject to consecutive measurements of a squeezed action. We demonstrate a breakdown of dynamical realism in a wide parameter range that is maximized in a scaling limit of extreme squeezing, where it is based on measurements of smooth observables, implying that macroscopic realism is not valid in the harmonic oscillator. We propose an indirect experimental test of these predictions with entangled photons by demonstrating that local realism in a composite system implies dynamical realism in a subsystem.

  17. Reinvestigation of the Branimycin Stereochemistry at Position 17-C.

    PubMed

    Čikoš, Ana; Triballeau, Nicolas; Hubbard, Paul A; Žiher, Dinko; Stouten, Pieter F W; Doyon, Julien G P-O; Deschrijver, Tiny; Wouters, Johan; Lépine, Renaud H M; Saniere, Laurent

    2016-02-19

    A conformational study of branimycin was performed using single-crystal X-ray crystallography to characterize the solid-state form, while a combination of NMR spectroscopy and molecular modeling was employed to gain information about the solution structure. Comparison of the crystal structure with its solution counterpart showed no significant differences in conformation, confirming the relative rigidity of the tricyclic system. However, these experiments revealed that the formerly proposed stereochemistry of branimycin at 17-C should be revised.

  18. Stereochemistry of bistricyclic aromatic enes and related polycyclic systems.

    PubMed

    Biedermann, P Ulrich; Agranat, Israel

    2014-01-01

    Bistricyclic aromatic enes (BAEs) and related polycyclic systems are a class of molecular materials that display a rich variety of conformations, dynamic stereochemistry and switchable chirality, color, and spectroscopic properties. This is due to the a subtle interplay of the inherent preference for planarity of aromatic systems and the competing necessity of non-planarity due to intramolecular overcrowding in the fjord regions built into the general molecular structure of BAEs. The conformational, dynamic, and spectroscopic properties may be designed and fine-tuned, e.g., by variation of the bridging groups X and Y, the overcrowding in the fjord regions, extensions of the aromatic system, or other modifications of the general BAE structure, based on the fundamental understanding of the structure-property relationships (SPR). The present review provides an analysis of the conformational spaces and the dynamic stereochemistry of overcrowded bistricyclic aromatic enes applying fundamental symmetry considerations. The symmetry analysis presented here allows deeper insight into the conformations, chirality, and the mechanisms of the dynamic stereochemistry, and will be instrumental in future computational studies.

  19. Handling of tautomerism and stereochemistry in compound registration.

    PubMed

    Gobbi, Alberto; Lee, Man-Ling

    2012-02-27

    Automated registration of compounds from external sources is necessitated by the numerous compound acquisitions from vendors and by the increasing number of collaborations with external partners. A prerequisite for automating compound registration is a robust module for determining the structural novelty of the input structures. Any such tool needs to be able to take uncertainty about stereochemistry into account and to identify tautomeric forms of the same compound. It also needs to validate structures for potential mistakes in connectivity and stereochemistry. Genentech has implemented a Structure Normalization Module based on toolkits offered by OpenEye Scientific Software. The module is incorporated in a graphical application for single compound registration and in scripts for bulk registration. It is also used for checking compounds submitted by our collaborators via partner-specific Internet sites. The Genentech Structure Normalization Module employs the widely used V2000 molfile format to accommodate structures received from a wide variety of sources. To determine how much information is known about the stereochemistry of each compound, the module requires a separate stereochemical assignment. A structural uniqueness check is performed by comparing the canonical SMILES of a standard tautomer. This paper offers a discussion of the steps taken to validate the chemical structure and generate the canonical SMILES of the standard tautomer. It also describes the integration of the validation module in compound registration pathways.

  20. Revised stereochemistry of ceramide-trafficking inhibitor HPA-12 by X-ray crystallography analysis.

    PubMed

    Ueno, Masaharu; Huang, Yi-Yong; Yamano, Akihito; Kobayashi, Shū

    2013-06-07

    In response to Berkeš's report revising the stereochemistry of HPA-12, an important ceramide-trafficking inhibitor that was discovered and synthesized and its stereochemistry determined in 2001, the synthesis and the stereochemistry were reinvestigated. A large-scale synthetic method for HPA-12 based on a Zn-catalyzed asymmetric Mannich-type reaction in water was developed. Single crystals of HPA-12 for X-ray crystallographic analysis were obtained from ethyl propionate/n-hexane, and the stereochemistry was definitely determined to be 1R,3S, consistent with Berkeš's revised structure.

  1. Introduction of the (-)-berkelic acid side chain and assignment of the C-22 stereochemistry.

    PubMed

    Wu, Xiaoxing; Zhou, Jingye; Snider, Barry B

    2009-08-21

    A Kiyooka aldol condensation of an aldehyde with a trimethylsilyl ketene acetal and the oxazaborolidinone prepared from N-Ts-(S)-valine gives two of the four possible aldol adducts, which were oxidized and deprotected to complete the synthesis of (-)-berkelic acid and (-)-22-epi-berkelic acid. This synthesis establishes the absolute stereochemistry and assigns the stereochemistry at C-22. A biosynthetic pathway is proposed that is consistent with the known absolute stereochemistry at the quaternary carbon of spiciferone A, spicifernin, and berkelic acid and provides a simple explanation for the differing stereochemistry at C-18 and C-19 of spicifernin and berkelic acid.

  2. Ideas of Western Man: Expressionism and Realism: English, Humanities.

    ERIC Educational Resources Information Center

    Hall, Peggy; Knappe, Shirley

    The course, "Ideas of Western Man: Expressionism and Realism," involves the analysis of some predominant schools and man's changing thought through the study of literature. In studying Expressionism and Realism as they have affected contemporary American Culture, philosophy is emphasized, and painting, sculpture, and music are used for…

  3. Dramaturging Non-Realism: Creating a New Vocabulary.

    ERIC Educational Resources Information Center

    Haring-Smith, Tori

    2003-01-01

    Discusses the experiences of a professional and academic dramaturg as she learns how to respond to non-realist plays. Proposes that non-realism is not simply the absence of realism but is a form in itself. Presents a vocabulary for non-realist texts. Notes that to create this vocabulary the features of its style should be defined. Discusses the…

  4. Comparison of Linear Microinstability Calculations of Varying Input Realism

    SciTech Connect

    G. Rewoldt

    2003-09-08

    The effect of varying ''input realism'' or varying completeness of the input data for linear microinstability calculations, in particular on the critical value of the ion temperature gradient for the ion temperature gradient mode, is investigated using gyrokinetic and gyrofluid approaches. The calculations show that varying input realism can have a substantial quantitative effect on the results.

  5. Exorcising the Racism Phantasm: Racial Realism in Educational Research

    ERIC Educational Resources Information Center

    Blaisdell, Benjamin

    2016-01-01

    Based on a 3-year ethnographic project at a public elementary school in North Carolina, this article discusses how the concept of racial realism can be useful to researchers trying to live up to the goals of critical race studies in school-based research. Racial realism maintains that racism is a permanent aspect of U.S. society and schools. A…

  6. Earth Observation System Flight Dynamics System Covariance Realism

    NASA Technical Reports Server (NTRS)

    Zaidi, Waqar H.; Tracewell, David

    2016-01-01

    This presentation applies a covariance realism technique to the National Aeronautics and Space Administration (NASA) Earth Observation System (EOS) Aqua and Aura spacecraft based on inferential statistics. The technique consists of three parts: collection calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics.

  7. Emergent Paradigm: Critical Realism and Transformative Research in Educational Administration

    ERIC Educational Resources Information Center

    Egbo, Benedicta

    2005-01-01

    This paper explores the prospects of using critical realism as a guiding philosophy for critical inquiry in the field of educational administration. A relatively recent philosophy in the social sciences, critical realism offers an alternative framework for researchers engaged in empirical work that is aimed at transforming undesirable social…

  8. Response: Critical Realism--Response to Longhofer and Floersch

    ERIC Educational Resources Information Center

    Briar-Lawson, Katharine

    2012-01-01

    This article addresses key challenges posed by critical realism, proposed by Longhofer and Floersch, as a philosophical underpinning for a science of social work. As a response to Longhofer and Floersch, it is argued that critical realism may be instructive in debates about structural conditions that dictate more inclusive interventions and…

  9. Measurement contextuality is implied by macroscopic realism

    SciTech Connect

    Chen Zeqian; Montina, A.

    2011-04-15

    Ontological theories of quantum mechanics provide a realistic description of single systems by means of well-defined quantities conditioning the measurement outcomes. In order to be complete, they should also fulfill the minimal condition of macroscopic realism. Under the assumption of outcome determinism and for Hilbert space dimension greater than 2, they were all proved to be contextual for projective measurements. In recent years a generalized concept of noncontextuality was introduced that applies also to the case of outcome indeterminism and unsharp measurements. It was pointed out that the Beltrametti-Bugajski model is an example of measurement noncontextual indeterminist theory. Here we provide a simple proof that this model is the only one with such a feature for projective measurements and Hilbert space dimension greater than 2. In other words, there is no extension of quantum theory providing more accurate predictions of outcomes and simultaneously preserving the minimal labeling of events through projective operators. As a corollary, noncontextuality for projective measurements implies noncontextuality for unsharp measurements. By noting that the condition of macroscopic realism requires an extension of quantum theory, unless a breaking of unitarity is invoked, we arrive at the conclusion that the only way to solve the measurement problem in the framework of an ontological theory is by relaxing the hypothesis of measurement noncontextuality in its generalized sense.

  10. Retinal vascular tree reconstruction with anatomical realism.

    PubMed

    Lin, Kai-Shun; Tsai, Chia-Ling; Tsai, Chih-Hsiangng; Sofka, Michal; Chen, Shih-Jen; Lin, Wei-Yang

    2012-12-01

    Motivated by the goals of automatically extracting vessel segments and constructing retinal vascular trees with anatomical realism, this paper presents and analyses an algorithm that combines vessel segmentation and grouping of the extracted vessel segments. The proposed method aims to restore the topology of the vascular trees with anatomical realism for clinical studies and diagnosis of retinal vascular diseases, which manifest abnormalities in either venous and/or arterial vascular systems. Vessel segments are grouped using extended Kalman filter which takes into account continuities in curvature, width, and intensity changes at the bifurcation or crossover point. At a junction, the proposed method applies the minimum-cost matching algorithm to resolve the conflict in grouping due to error in tracing. The system was trained with 20 images from the DRIVE dataset, and tested using the remaining 20 images. The dataset contained a mixture of normal and pathological images. In addition, six pathological fluorescein angiogram sequences were also included in this study. The results were compared against the groundtruth images provided by a physician, achieving average success rates of 88.79% and 90.09%, respectively.

  11. Julio Cortázar quotes on normal and abnormal movements: magical realism or reality?

    PubMed

    Merello, Marcelo

    2006-08-01

    Together with Mario Vargas Llosa and Gabriel García Márquez, Julio Cortázar was one of the most representative authors of the Latin American magical realism genre. Within his extensive body of work, many descriptions of characters suffering physical disabilities, as well as situations suggesting such medical conditions, can be extracted. In this review, two short stories by Cortázar are presented. In the first one, the main character could easily be a man suffering from corticobasal degeneration; in the second, an old woman with symptoms suggestive of progressive supranuclear palsy is clearly depicted. Despite the fact that one of the main ingredients in Cortázar's magical realism is fiction, cases described here fit real medical conditions quite well, making it hard to believe that they represent purely fantastic descriptions rather than the product of Cortázar's inquisitive observation and the description of real patients.

  12. Observing Local Realism Violations with a Combination of Sensitive and Insensitive Detectors

    SciTech Connect

    Yurke, B.; Stoler, D.

    1997-12-01

    Several systems are exhibited in which the establishment of local realism violation is achieved even when some of the detectors employed are insensitive. The insensitive detectors are homodyne detectors whose task is to determine if the amplitude of a coherent state is {alpha} or {minus}{alpha} . This determination can be achieved with low quantum efficiency detectors when {vert_bar}{alpha}{vert_bar} is large. The other detectors employed determine whether there is an even number or an odd number of photons in a state. These detectors are sensitive since they are required to resolve the difference of one photon. For the examples given, the local realism violation is not diminished as {vert_bar}{alpha}{vert_bar} is increased. {copyright} {ital 1997} {ital The American Physical Society}

  13. Total Synthesis and Absolute Stereochemistry of the Proteasome Inhibitors Cystargolides A and B

    PubMed Central

    Tello-Aburto, Rodolfo; Hallada, Liam P.; Niroula, Doleshwar; Rogelj, Snezna

    2015-01-01

    The absolute stereochemistry of the cystargolides was determined by total synthesis. Evaluation of synthetic cystargolides and derivatives showed that the natural (2S,3R) stereochemistry is essential for activity. Moreover, benzyl esters (−)-10 and (−)-15 were found to be about 100 times more potent, and to selectively kill MCF-7 cancerous cells. PMID:26400369

  14. Total synthesis and absolute stereochemistry of the proteasome inhibitors cystargolides A and B.

    PubMed

    Tello-Aburto, Rodolfo; Hallada, Liam P; Niroula, Doleshwar; Rogelj, Snezna

    2015-10-28

    The absolute stereochemistry of the cystargolides was determined by total synthesis. Evaluation of synthetic cystargolides and derivatives showed that the natural (2S,3R) stereochemistry is essential for activity. Moreover, benzyl esters (-)-10 and (-)-15 were found to be about 100 times more potent, and to selectively kill MCF-7 cancerous cells.

  15. Development of a Web-Based, Student-Centered Stereochemistry Tutorial

    ERIC Educational Resources Information Center

    Burrmann, Nicola J.; Moore, John W.

    2013-01-01

    A Web-based stereochemistry tutorial is described that details the core definitions and structural representations of stereochemistry in an organic chemistry course. The Cahn-Ingold-Prelog rules and their application for assigning "R" and "S" orientations to stereocenters and "E" and "Z" orientations to…

  16. A Simple and Novel Approach to Delineating Stereochemistry of Electrocyclic Reactions

    ERIC Educational Resources Information Center

    Mandal, Dipak K.

    2012-01-01

    The dynamic stereochemistry of electrocyclic reactions (a class of pericyclic reactions) stems from the operation of either conrotatory (con) or disrotatory (dis) mode of ring-closing and ring-opening processes. Difficulty is often encountered in depicting product stereochemistry resulting from such movements of substituents. A novel, simple,…

  17. Stereochemistry of enzymatic water addition to C=C bonds.

    PubMed

    Chen, Bi-Shuang; Otten, Linda G; Hanefeld, Ulf

    2015-01-01

    Water addition to carbon-carbon double bonds using hydratases is attracting great interest in biochemistry. Most of the known hydratases are involved in primary metabolism and to a lesser extent in secondary metabolism. New hydratases have recently been added to the toolbox, both from natural sources or artificial metalloenzymes. In order to comprehensively understand how the hydratases are able to catalyse the water addition to carbon-carbon double bonds, this review will highlight the mechanistic and stereochemical studies of the enzymatic water addition to carbon-carbon double bonds, focusing on the syn/anti-addition and stereochemistry of the reaction.

  18. Functional realism: a defense of narrative medicine.

    PubMed

    Vannatta, Seth; Vannatta, Jerry

    2013-02-01

    In this paper we (1) define and describe the practice of narrative medicine, (2) reveal the need for narrative medicine by exposing the presuppositions that give rise to its discounting, including a reductive empiricism and a strict dichotomy between scientific fact and narrative value, (3) show evidence of the effects of education in narrative competence in the medical clinic, and (4) present Peircean realism as the proper conceptual model for our argument that the medical school curriculum committees should give space to the employment of the scientific and literary knowledge in medical practice. On account of our argument, we contend that the medical community should tend to latitude and openness with regard to the tools we use to resolve medical problems. These tools include both biomedical and narrative knowledge.

  19. Improving the physiological realism of experimental models.

    PubMed

    Vinnakota, Kalyan C; Cha, Chae Y; Rorsman, Patrik; Balaban, Robert S; La Gerche, Andre; Wade-Martins, Richard; Beard, Daniel A; Jeneson, Jeroen A L

    2016-04-06

    The Virtual Physiological Human (VPH) project aims to develop integrative, explanatory and predictive computational models (C-Models) as numerical investigational tools to study disease, identify and design effective therapies and provide an in silico platform for drug screening. Ultimately, these models rely on the analysis and integration of experimental data. As such, the success of VPH depends on the availability of physiologically realistic experimental models (E-Models) of human organ function that can be parametrized to test the numerical models. Here, the current state of suitable E-models, ranging from in vitro non-human cell organelles to in vivo human organ systems, is discussed. Specifically, challenges and recent progress in improving the physiological realism of E-models that may benefit the VPH project are highlighted and discussed using examples from the field of research on cardiovascular disease, musculoskeletal disorders, diabetes and Parkinson's disease.

  20. Happiness, Psychology, and Degrees of Realism.

    PubMed

    Lavazza, Andrea

    2016-01-01

    The recent emphasis on a realist ontology that cannot be overshadowed by subjectivist or relativist perspectives seems to have a number of consequences for psychology as well. My attempt here is to analyse the relationship between happiness as a state of the individual and the states of the external world and the brain events related to (or, in some hypotheses, causally responsible for) its occurrence. It can be maintained that different degrees of realism are suitable to describe the states of happiness and this fact might have relevant psychological implications, namely for the so-called positive psychology. This is especially true now that there are methods available to induce subjective states of happiness unrelated to the external conditions usually taken to be linked to such states.

  1. Happiness, Psychology, and Degrees of Realism

    PubMed Central

    Lavazza, Andrea

    2016-01-01

    The recent emphasis on a realist ontology that cannot be overshadowed by subjectivist or relativist perspectives seems to have a number of consequences for psychology as well. My attempt here is to analyse the relationship between happiness as a state of the individual and the states of the external world and the brain events related to (or, in some hypotheses, causally responsible for) its occurrence. It can be maintained that different degrees of realism are suitable to describe the states of happiness and this fact might have relevant psychological implications, namely for the so-called positive psychology. This is especially true now that there are methods available to induce subjective states of happiness unrelated to the external conditions usually taken to be linked to such states. PMID:27536261

  2. Cost Realism Handbook for Assuring More Realistic Contractor Cost Proposals

    DTIC Science & Technology

    1985-05-01

    realism. Solicitation: Specify cost realism in addition ,:) Government estimated cost as cost evaluation sub- - ieria in the solicitation and specify the...Analogy techniques involve extrapolations from actual costs for similar systems. Other techniques may include the use of industry wide factors. Parametric...of sources (e.g., actual costs for similar systems and industry wide factors) may be used to supplement the estimates based on specific contractor

  3. Unified Synthesis of 10-Oxygenated Lycopodium Alkaloids: Impact of C10-Stereochemistry on Reactivity.

    PubMed

    Saha, Mrinmoy; Li, Xin; Collett, Nathan D; Carter, Rich G

    2016-07-15

    The pronounced impact of the C10 stereochemistry on the successful construction of a polycyclic Lycopodium alkaloid scaffold has been explored. A wide range of reaction conditions and functionality were investigated to control a keto sulfone Michael addition to construct the C7-C12 linkage. An unexpected, overriding impact of the C10 stereochemistry in stereoselectivity and reaction rate in the Michael addition was observed. Furthermore, divergent reactivity of a conformationally accelerated, intramolecular Mannich cyclization based on the C10 stereochemistry was discovered. The successful execution of this synthetic route resulted in the total synthesis of all three known 10-oxygenated Lycopodium alkaloids: 10-hydroxylycopodine, paniculine, and deacetylpaniculine.

  4. Relationships between the stereochemistry and biological activity of fungal phytotoxins.

    PubMed

    Evidente, Antonio; Andolfi, Anna; Cimmino, Alessio

    2011-10-01

    Toxins produced by phytopathogenic fungi assume great importance because of their involvement in several plant diseases. Although such pathogens are known to have seriously damaged crops, forest, and environmental resources, they represent a very important tool to develop new environmentally friendly herbicides and fungicides. This review deals with the relationships between the biological activity of some phytotoxins produced by pathogenic fungi for major forest plants and for damaging weeds and their stereochemistry. In particular, the methods used to determine their relative and/or absolute configuration will be illustrated. These include the application of Mosher's and Murata's methods, X-ray diffractometric analysis, circular dichroism, and the use of computational methods to determine the theoretical optical rotatory power as well as the CD spectrum. The importance of determining the absolute configuration to achieve the total synthesis of some phytotoxins, interesting for their potential practical application, is also discussed.

  5. Costs and benefits of realism and optimism

    PubMed Central

    Bortolotti, Lisa; Antrobus, Magdalena

    2015-01-01

    Purpose of review What is the relationship between rationality and mental health? By considering the psychological literature on depressive realism and unrealistic optimism, it was hypothesized that, in the context of judgments about the self, accurate cognitions are psychologically maladaptive and inaccurate cognitions are psychologically adaptive. Recent studies recommend being cautious in drawing any general conclusion about the style of thinking and mental health. Recent findings Recent investigations suggest that people with depressive symptoms are more accurate than controls in tasks involving time perception and estimates of personal circumstances, but not in other tasks. Unrealistic optimism remains a robust phenomenon across a variety of tasks and domains, and researchers are starting to explore its neural bases. However, the challenge is to determine to what extent and in what way unrealistic optimism is beneficial. Summary We should revisit the hypothesis that optimistic cognitions are psychologically adaptive, whereas realistic thinking is not. Realistic beliefs and expectations can be conducive to wellbeing and good functioning, and wildly optimistic cognitions have considerable psychological costs. PMID:25594418

  6. Van't Hoff, Le Bel, and the Development of Stereochemistry: A Reassessment.

    ERIC Educational Resources Information Center

    Grossman, Robert B.

    1989-01-01

    Shows that two theories of stereochemistry were very different theories, grounded in different assumptions and were intended to explain different phenomena. Presents the original theories and later developments which caused a blending of the theories. (Author/MVL)

  7. Determination of the Absolute Stereochemistry of Secondary Alcohols: An Advanced Organic Chemistry Experiment for Undergraduate Students.

    ERIC Educational Resources Information Center

    Bandaranayake, Wickramasinghe M.

    1980-01-01

    Describes experiments which can be completed in five four-hour laboratory sessions, including two synthesis (alpha-phenylbutyric and alpha-phenylbutyric acid anhydride) and determining the absolute stereochemistry of secondary alcohols using the synthetic products. (JN)

  8. Stereochemistry of 10-sulfoxidation catalyzed by a soluble delta9 desaturase

    SciTech Connect

    Tremblay, A.E.; Shanklin, J.; Tan, N.; Whittle, E.; Hodgson, D. J.; Dawson, B.; Buist, P. H.

    2010-03-21

    The stereochemistry of castor stearoyl-ACP 9 desaturase-mediated 10-sulfoxidation has been determined. This was accomplished by 19F NMR analysis of a fluorine-tagged product, 18-fluoro-10-thiastearoyl ACP S-oxide, in combination with a chiral solvating agent, (R)-AMA. Sulfoxidation proceeds with the same stereoselectivity as hydrogen removal from the parent stearoyl substrate. These data validate the use of thia probes to determine the stereochemistry and cryptoregiochemistry of desaturase-mediated oxidations.

  9. Asymmetric total synthesis of (-)-lundurine B and determination of its absolute stereochemistry.

    PubMed

    Nakajima, Masaya; Arai, Shigeru; Nishida, Atsushi

    2015-04-01

    A total synthesis of the Kopsia tenuis alkaloid (-)-lundurine B has been achieved. A quaternary chiral carbon has been created by an asymmetric deprotonation using a symmetric spiro cyclohexanone intermediate with a chiral lithium amide. The hexacyclic skeleton was sequentially constructed through metal-mediated reactions. The absolute stereochemistry of intermediate 5 has been unambiguously established by X-ray crystallographic analysis. This is the first description of the absolute stereochemistry of Kopsia tenuis alkaloids based on chemical synthesis.

  10. Absolute Stereochemistry of 1,2-Diols from Lipids of Thermomicrobia.

    PubMed

    Lagutin, Kirill; Wong, Herbert; Vyssotski, Mikhail; MacKenzie, Andrew

    2016-03-01

    1,2-Diol based phospholipids are a well-known feature of bacteria from the class Thermomicrobia. Since these bacteria contain only lipids with an alkyldiol-1-phosphate backbone instead of sn-glycero-3-phosphate, it is important to elucidate the stereochemistry of the 1,2-diols. We have studied the absolute stereochemistry of long-chain 1,2-diols isolated from Thermorudis pharmacophila (formerly known as Thermomicrobia sp. WKT50.2) by nuclear magnetic resonance (NMR) using α-methoxyphenylacetic acid (MPA). Low-temperature (-60 °C) NMR of bis-(R)-MPA ester showed (R) stereochemistry of the 1,2-diols. This is the first report concerning the stereochemistry of natural 1,2-diols, which replace the glyceride moiety in phospholipids. The (R) stereochemistry of the diols is expected as it is the same configuration as for the common bacterial lipid backbone-sn-glycero-3-phosphate. This is the first application of low-temperature NMR of a single MPA derivative for assignment of stereochemistry of natural 1,2-diols. The results were confirmed by the comparison of NMR data with bis-(R)-MPA ester of (R) and rac-1,2-octanediol.

  11. An Essay for Educators: Epistemological Realism Really is Common Sense

    NASA Astrophysics Data System (ADS)

    Cobern, William W.; Loving, Cathleen C.

    2008-04-01

    “What is truth?” Pontius Pilot asked Jesus of Nazareth. For many educators today this question seems quaintly passé. Rejection of “truth” goes hand-in-hand with the rejection of epistemological realism. Educational thought over the last decade has instead been dominated by empiricist, anti-realist, instrumentalist epistemologies of two types: first by psychological constructivism and later by social constructivism. Social constructivism subsequently has been pressed to its logical conclusion in the form of relativistic multiculturalism. Proponents of both psychological constructivism and social constructivism value knowledge for its utility and eschew as irrelevant speculation any notion that knowledge is actually about reality. The arguments are largely grounded in the discourse of science and science education where science is “western” science; neither universal nor about what is really real. The authors defended the notion of science as universal in a previous article. The present purpose is to offer a commonsense argument in defense of critical realism as an epistemology and the epistemically distinguished position of science (rather than privileged) within a framework of epistemological pluralism. The paper begins with a brief cultural survey of events during the thirty-year period from 1960-1990 that brought many educators to break with epistemological realism and concludes with comments on the pedagogical importance of realism. Understanding the cultural milieu of the past forty years is critical to understanding why traditional philosophical attacks on social constructivist ideas have proved impotent defenders of scientific realism.

  12. Time perception and depressive realism: judgment type, psychophysical functions and bias.

    PubMed

    Kornbrot, Diana E; Msetfi, Rachel M; Grimwood, Melvyn J

    2013-01-01

    The effect of mild depression on time estimation and production was investigated. Participants made both magnitude estimation and magnitude production judgments for five time intervals (specified in seconds) from 3 sec to 65 sec. The parameters of the best fitting psychophysical function (power law exponent, intercept, and threshold) were determined individually for each participant in every condition. There were no significant effects of mood (high BDI, low BDI) or judgment (estimation, production) on the mean exponent, n = .98, 95% confidence interval (.96-1.04) or on the threshold. However, the intercept showed a 'depressive realism' effect, where high BDI participants had a smaller deviation from accuracy and a smaller difference between estimation and judgment than low BDI participants. Accuracy bias was assessed using three measures of accuracy: difference, defined as psychological time minus physical time, ratio, defined as psychological time divided by physical time, and a new logarithmic accuracy measure defined as ln (ratio). The ln (ratio) measure was shown to have approximately normal residuals when subjected to a mixed ANOVA with mood as a between groups explanatory factor and judgment and time category as repeated measures explanatory factors. The residuals of the other two accuracy measures flagrantly violated normality. The mixed ANOVAs of accuracy also showed a strong depressive realism effect, just like the intercepts of the psychophysical functions. There was also a strong negative correlation between estimation and production judgments. Taken together these findings support a clock model of time estimation, combined with additional cognitive mechanisms to account for the depressive realism effect. The findings also suggest strong methodological recommendations.

  13. Does Quantum Physics Refute Realism, Materialism and Determinism?

    ERIC Educational Resources Information Center

    Bunge, Mario

    2012-01-01

    It is argued that the correct answer to the three questions in the title is "no": that the theses being denied derive from traditional philosophy, not from the way the quantum theories are used. For example, the calculation of the energy spectrum of an atom assumes the autonomous existence of the atom, rather than its dependence upon the observer.…

  14. Stereochemistry of ulapualides, a new family of tris-oxazole-containing macrolide ionophores from marine nudibranchs. A molecular mechanics study

    NASA Astrophysics Data System (ADS)

    Maddock, John; Pattenden, Gerald; Wight, Paul G.

    1993-10-01

    A molecular mechanics study of the marine metabolite ulapualide A, which is suggested to have ionophorie properties, has been carried out on various metal chelated complexes in order to predict the stereochemistry of the natural product. The results suggest a stereochemistry for ulapualide A which is closely similar to structurally related marine metabolites, whose stereochemistries have been established by X-ray crystallography and by partial synthesis.

  15. Looking for treasure in stereochemistry-land. A path marked by curiosity, obstinacy, and serendipity.

    PubMed

    Juaristi, Eusebio

    2012-06-01

    Over the past 40 years, much of my research has evolved around various topics of conformational analysis and asymmetric synthesis. This Perspective describes some of my salient contributions in eight different areas of organic stereochemistry: (1) conformational analysis of six-membered rings, (2) evaluation of stereoelectronic interactions in (1)J(C-H) one-bond coupling constants in six-membered rings, (3) eclipsed conformation in cis-2-tert-butyl-5-(tert-butylsulfonyl)-1,3-dioxane, (4) determination of enthalpic and entropic contributions to ΔG°(CH(2)Ph) and ΔG°(t-Bu), (5) study of the "attractive gauche effect" in O-C-C-O segments, (6) examination of salt effects on conformational equilibria, (7) asymmetric synthesis of β-amino acids, and (8) asymmetric organocatalysis and "Green" chemistry. It will be appreciated that a basic understanding of the principles of physical organic chemistry has been essential in all projects. Furthermore, curiosity, enthusiasm, obstinacy, and paying attention to unexpected observations will lead to many new (stereo)chemical discoveries.

  16. Real Gardens with Real Toads: A New Sort of Realism in Poetry.

    ERIC Educational Resources Information Center

    Livingston, Myra Cohn

    1995-01-01

    Discusses realism in children's poetry and a New Realism which dates from the 1960s. Suggests that the denial of realism occupies much of the efforts of Mother Goose reformers, who have carried on "for eons" over the violence, mayhem, and cruelty in the old nursery rhymes. (RS)

  17. Scientific Symbiosis Represents the Mutual Benefit of Iteratively Adopting the Perspective of Realism and Instrumentalism

    ERIC Educational Resources Information Center

    Cacioppo, John T.; Berntson, Gary G.; Semin, Gu R.

    2005-01-01

    This article presents comments on "Psychology Needs Realism not Instrumentalism" by B. Haig, "Ontological and Epistemic Claims of Realism and Instrumentalism" by Lau and "The Scientific Denial of the Real and the Dialectic of Scientism and Humanism" by Ramey and Chrysikou which were all comments on the original article "Realism, Instrumentalism,…

  18. Piloting Augmented Reality Technology to Enhance Realism in Clinical Simulation.

    PubMed

    Vaughn, Jacqueline; Lister, Michael; Shaw, Ryan J

    2016-09-01

    We describe a pilot study that incorporated an innovative hybrid simulation designed to increase the perception of realism in a high-fidelity simulation. Prelicensure students (N = 12) cared for a manikin in a simulation lab scenario wearing Google Glass, a wearable head device that projected video into the students' field of vision. Students reported that the simulation gave them confidence that they were developing skills and knowledge to perform necessary tasks in a clinical setting and that they met the learning objectives of the simulation. The video combined visual images and cues seen in a real patient and created a sense of realism the manikin alone could not provide.

  19. Effects of stereochemistry and copolymerization on the LCST of PNIPAm.

    PubMed

    de Oliveira, Tiago E; Mukherji, Debashish; Kremer, Kurt; Netz, Paulo A

    2017-01-21

    Poly(N-isopropylacrylamide) (PNIPAm) is a smart polymer that presents a lower critical transition temperature (LCST) of 305 K. Interestingly, this transition point falls within the range of the human body temperature, making PNIPAm a highly suitable candidate for bio-medical applications. However, it is sometimes desirable to have a rather flexible tuning of the LCST of these polymers to further increase their range of applications. In this work, we use all-atom molecular dynamics simulations to study the LCST of PNIPAm-based (co-)polymers. We study different molecular architectures where the polymer sequences are tuned either by modifying its stereochemistry or by the co-polymerization of PNIPAm with acrylamide (Am) units. Our analysis connects global polymer conformations with the microscopic intermolecular interactions. These findings suggest that the collapse of a PNIPAm chain upon heating is dependent on the hydration structure around the monomers, which is strongly dependent on the tacticity and the presence of more hydrophilic acrylamide monomers. Our results are found to be in good agreement with the existing experimental data.

  20. Effects of stereochemistry and copolymerization on the LCST of PNIPAm

    NASA Astrophysics Data System (ADS)

    de Oliveira, Tiago E.; Mukherji, Debashish; Kremer, Kurt; Netz, Paulo A.

    2017-01-01

    Poly(N-isopropylacrylamide) (PNIPAm) is a smart polymer that presents a lower critical transition temperature (LCST) of 305 K. Interestingly, this transition point falls within the range of the human body temperature, making PNIPAm a highly suitable candidate for bio-medical applications. However, it is sometimes desirable to have a rather flexible tuning of the LCST of these polymers to further increase their range of applications. In this work, we use all-atom molecular dynamics simulations to study the LCST of PNIPAm-based (co-)polymers. We study different molecular architectures where the polymer sequences are tuned either by modifying its stereochemistry or by the co-polymerization of PNIPAm with acrylamide (Am) units. Our analysis connects global polymer conformations with the microscopic intermolecular interactions. These findings suggest that the collapse of a PNIPAm chain upon heating is dependent on the hydration structure around the monomers, which is strongly dependent on the tacticity and the presence of more hydrophilic acrylamide monomers. Our results are found to be in good agreement with the existing experimental data.

  1. Accurate stereochemistry for two related 22,26-epiminocholestene derivatives

    SciTech Connect

    Vega-Baez, José Luis; Sandoval-Ramírez, Jesús; Meza-Reyes, Socorro; Montiel-Smith, Sara; Gómez-Calvario, Victor; Bernès, Sylvain

    2008-04-01

    Regioselective opening of ring E of solasodine under various conditions afforded (25R)-22,26-epimino@@cholesta-5,22(N)-di@@ene-3β,16β-diyl diacetate (previously known as 3,16-diacetyl pseudosolasodine B), C{sub 31}H{sub 47}NO{sub 4}, or (22S,25R)-16β-hydr@@oxy-22,26-epimino@@cholesta-5-en-3β-yl acetate (a derivative of the naturally occurring alkaloid oblonginine), C{sub 29}H{sub 47}NO{sub 3}. In both cases, the reactions are carried out with retention of chirality at the C16, C20 and C25 stereogenic centers, which are found to be S, S and R, respectively. Although pseudosolasodine was synthesized 50 years ago, these accurate assignments clarify some controversial points about the actual stereochemistry for these alkaloids. This is of particular importance in the case of oblonginine, since this compound is currently under consideration for the treatment of aphasia arising from apoplexy; the present study defines a diastereoisomerically pure compound for pharmacological studies.

  2. Total Synthesis, Assignment of the Relative and Absolute Stereochemistry, and Structural Reassignment of Phostriecin (aka Sultriecin)

    PubMed Central

    Burke, Christopher P.; Haq, Nadia; Boger, Dale L.

    2010-01-01

    A total synthesis of phostriecin (2) previously known as sultriecin (1), its structural reassignment as a phosphate versus sulfate monoester, and the assignment of its relative and absolute stereochemistry are disclosed herein. Key elements of the work, which provided first the originally assigned sulfate monoester 1 and then the reassigned and renamed phosphate monoester 2, relied on diagnostic 1H NMR spectroscopic properties of the natural product for the assignment of relative and absolute stereochemistry as well as the subsequent structural reassignment, and a convergent asymmetric total synthesis to provide the unequivocal authentic materials. Key steps of the synthetic approach include a Brown allylation for diastereoselective introduction of the C9 stereochemistry, an asymmetric CBS reduction to establish the lactone C5-stereochemistry, diastereoselective oxidative ring expansion of an α-hydroxyfuran to access the pyran lactone precursor, and single-step installation of the sensitive Z,Z,E-triene unit through a chelation-controlled cuprate addition with installation of the C11 stereochemistry. The approach allows ready access to analogues that can now be used to probe important structural features required for PP2A inhibition, the mechanism of action defined herein. PMID:20108904

  3. Total synthesis, assignment of the relative and absolute stereochemistry, and structural reassignment of phostriecin (aka Sultriecin).

    PubMed

    Burke, Christopher P; Haq, Nadia; Boger, Dale L

    2010-02-24

    A total synthesis of phostriecin (2), previously known as sultriecin (1), its structural reassignment as a phosphate versus sulfate monoester, and the assignment of its relative and absolute stereochemistry are disclosed herein. Key elements of the work, which provided first the originally assigned sulfate monoester 1 and then the reassigned and renamed phosphate monoester 2, relied on diagnostic (1)H NMR spectroscopic properties of the natural product for the assignment of relative and absolute stereochemistry as well as the subsequent structural reassignment, and a convergent asymmetric total synthesis to provide the unequivocal authentic materials. Key steps of the synthetic approach include a Brown allylation for diastereoselective introduction of the C9 stereochemistry, an asymmetric CBS reduction to establish the lactone C5-stereochemistry, diastereoselective oxidative ring expansion of an alpha-hydroxyfuran to access the pyran lactone precursor, and single-step installation of the sensitive Z,Z,E-triene unit through a chelation-controlled cuprate addition with installation of the C11 stereochemistry. The approach allows ready access to analogues that can now be used to probe important structural features required for protein phosphatase 2A inhibition, the mechanism of action defined herein.

  4. Realism and Romance: The Study of Media Effects.

    ERIC Educational Resources Information Center

    Tuchman, Gaye

    1993-01-01

    Compares and contrasts two studies representing diametrical approaches (Romanticism versus Realism) toward the issue of agency and media effects: P. Willis's "Common Culture" and W. A. Gamson's "Talking Politics." Argues that both studies find that people make their own uses of media. (SR)

  5. Still Playing It Safe: Restricted Realism in Teen Novels

    ERIC Educational Resources Information Center

    Abramson, Jane

    1976-01-01

    The restrictions on teen fiction result in books that succeed only in mirroring a slick surface realism that too often acts as a cover-up. It disguises the fact that, at their core, most realistic novels are unrealistic and, far worse, dishonest. (Author)

  6. A New Sort of Realism in Poetry--Part 2.

    ERIC Educational Resources Information Center

    Livingston, Myra Cohn

    1995-01-01

    Discusses challenges to realistic poetry in school libraries. Addresses what New Realism is being accepted today in the world of poetry. Discusses the author's experiences in dealing with a publisher who wanted a book of poetry about jolly parents and patient grandparents, not a book about families as they really are. (RS)

  7. A Quest to Explain the Extreme Realism in Newbery Books

    ERIC Educational Resources Information Center

    Miguez, Betsy Bryan; Goetting, Denise

    2006-01-01

    The quest to explain the extreme realism found in some Newbery Award books led the authors to discover that there is no unified view of childhood affecting children's literature today. While some adults feel that children must be protected against the evil surrounding them, others feel that they must be prepared to face the world in which they…

  8. The JPL Cost Risk Analysis Approach that Incorporates Engineering Realism

    NASA Technical Reports Server (NTRS)

    Harmon, Corey C.; Warfield, Keith R.; Rosenberg, Leigh S.

    2006-01-01

    This paper discusses the JPL Cost Engineering Group (CEG) cost risk analysis approach that accounts for all three types of cost risk. It will also describe the evaluation of historical cost data upon which this method is based. This investigation is essential in developing a method that is rooted in engineering realism and produces credible, dependable results to aid decision makers.

  9. An Exploration of Adolescents' Perceptions of Videogame Realism

    ERIC Educational Resources Information Center

    Malliet, Steven

    2006-01-01

    An attempt is made to translate the concept of perceived realism from the domain of general media studies to the domain of videogame studies. In order to make such a translation, a thorough knowledge and integration is required of the simulation aspects that distinguish videogames from older media such as film or television. The different meanings…

  10. Ontological and Epistemic Claims of Realism and Instrumentalism

    ERIC Educational Resources Information Center

    Lau, Michael Y.

    2005-01-01

    This article presents comments on "Realism, Instrumentalism, and Scientific Symbiosis: Psychological Theory as a Search for Truth and the Discovery of Solutions" by John T. Cacioppo, Gun R. Semin and Gary G. Berntson. While Lau admires the authors efforts to negotiate symbiosis with seemingly incommensurate realist and instrumentalist positions in…

  11. Navigating through virtual environments: visual realism improves spatial cognition.

    PubMed

    Meijer, Frank; Geudeke, Branko L; van den Broek, Egon L

    2009-10-01

    Recent advances in computer technology have significantly facilitated the use of virtual environments (VE) for small and medium enterprises (SME). However, achieving visual realism in such VE requires high investments in terms of time and effort, while its usefulness has not yet become apparent from research. Other qualities of VE, such as the use of large displays, proved its effectiveness in enhancing the individual user's spatial cognition. The current study assessed whether the same benefits apply for visual realism in VE. Thirty-two participants were divided into two groups, who explored either a photorealistic or a nonrealistic supermarket presented on a large screen. The participants were asked to navigate through the supermarket on a predetermined route. Subsequently, spatial learning was tested in four pen-and-paper tests that assessed how accurately they had memorized the route and the environment's spatial layout. The study revealed increased spatial learning from the photorealistic compared to the nonrealistic supermarket. Specifically, participants performed better on tests that involved egocentric spatial knowledge. The results suggest visual realism is useful because it increases the user's spatial knowledge in the VE. Therefore, the current study provides clear evidence that it is worthwhile for SME to invest in achieving visual realism in VE.

  12. An Essay for Educators: Epistemological Realism Really is Common Sense

    ERIC Educational Resources Information Center

    Cobern, William W.; Loving, Cathleen C.

    2008-01-01

    "What is truth?" Pontius Pilot asked Jesus of Nazareth. For many educators today this question seems quaintly passe. Rejection of "truth" goes hand-in-hand with the rejection of epistemological realism. Educational thought over the last decade has instead been dominated by empiricist, anti-realist, instrumentalist epistemologies of two types:…

  13. The role of testing realism on experimentally obtained stereotype strength.

    PubMed

    Hoffmann, Errol R; Whitfield, Richard C

    2011-01-01

    It has been shown (Hoffmann 2009) that pencil-and-paper tests, when used to determine stereotype strength, may yield data quite different to that obtained from hardware tests. The purpose of this research was to determine the level of realism required in order to have stereotypes that are consistent with real-world values. It is surprising that there does not appear to be any published research addressing this problem; all previous researches have considered either paper/pencil or hardware tests or sometimes both, but no level of simulation in between these techniques. In order to determine the effect of level of testing realism, a specific example was chosen to test, that of water tap operation stereotypes. Tests used verbal questioning, photographs of tap arrangements, a partial hardware arrangement and finally a full hardware setup. The results of these four levels of realism were very different and illustrated that, only with a full realistic simulation, did participants respond as might be expected in a real-world environment, illustrating the importance of testing realism when determining population stereotypes. This result has strong implications for product designers when selecting appropriate layouts of displays and controls and the linkages relating these.

  14. Critical Realism: An Emancipatory Philosophy for Applied Linguistics.

    ERIC Educational Resources Information Center

    Corson, David

    1997-01-01

    Presents six areas in applied linguistics that might be reformed: (1) the hegemonic nature of theories; (2) dictionary-making; (3) language planning; (4) linguistic nomenclatures; (5) the treatment of standard and non-standard varieties; and (6) the delivery of second language programs. Argues that if critical realism guided applied linguistics,…

  15. Young People: Victims of Realism in Books and in Life

    ERIC Educational Resources Information Center

    Jordan, June

    1973-01-01

    The author's credo is not to write anything unless it is usable, good news, or usable information to interdict and humanely supersede the reality of some particular bad news. She urges librarians and publishers to desist their perpetuation of the status quo under the mantle of realism. (Author/SJ)

  16. Quantum Realism, Information, and Epistemological Modesty

    NASA Astrophysics Data System (ADS)

    Grinbaum, Alexei

    2014-03-01

    It is usually asserted that physical theories, in particular quantum mechanics, support a certain view of what the world really is. To such claims I oppose an attitude of epistemological modesty. Ontological statements on the nature of reality, when made on the basis of quantum mechanics, appear unwarranted. I suggest that an epistemic loop connects physical theory grounded in informational notions, and a theory of information developed through a theoretical account of the physical support of information.

  17. Bringing critical realism to nursing practice: Roy Bhaskar's contribution.

    PubMed

    Williams, Lynne; Rycroft-Malone, Jo; Burton, Christopher R

    2017-04-01

    In the context of modern nursing practice that is embedded within complex social situations, critical discussions about the contribution of major philosophers are relevant and important. Whilst nurse theorists have advanced and shaped nursing as a discipline, other major philosophers can offer much to advance nursing enquiry. In this paper, we focus on philosopher Roy Bhaskar who, amongst others, developed critical realism, a philosophy for social science which connects with how many of us think about the world. Bhaskar's work focuses our attention on the interplay between structure and agency and on the search for the causative or generative mechanisms that explain the social world. Bhaskar was interested in human emancipation, and we suggest his work is of great importance to advance understanding of complex social situations. Critical realism has already been endorsed by a range of disciplines, especially in research which focuses on real problems and acknowledges the complexities of the social world. In recent evidence from healthcare literature, there has been a surge in research using realist methodology (realist evaluation and realist synthesis), which is underpinned by the philosophy of critical realism and which offers a different perspective to understanding nursing and healthcare problems through the realist lens. However, we suggest that sufficient attention is not always paid to the philosophical roots of this methodology. In this paper, we provide insight into Bhaskar's work and demonstrate how research positioned within critical realism and realist methodology can advance nursing and healthcare-related knowledge. Through shining a light on Bhaskar, we illustrate how critical realism philosophy is a natural fit with human and health science enquiry, including nursing.

  18. Evaluating Ketoreductase Exchanges as a Means of Rationally Altering Polyketide Stereochemistry.

    PubMed

    Annaval, Thibault; Paris, Cédric; Leadlay, Peter F; Jacob, Christophe; Weissman, Kira J

    2015-06-15

    Modular polyketide synthases (PKSs) are multidomain multienzymes responsible for the biosynthesis in bacteria of a wide range of polyketide secondary metabolites of clinical value. The stereochemistry of these molecules is an attractive target for genetic engineering in attempts to produce analogues exhibiting novel therapeutic properties. The exchange of ketoreductase (KR) domains in model PKSs has been shown in several cases to predictably alter the configuration of the β-hydroxy functionalities but not of the α-methyl groups. By systematic screening of a broad panel of KR domains, we have identified two donor KRs that afford modification of α-methyl group stereochemistry. To the best of our knowledge, this provides the first direct in vivo evidence of KR-catalyzed epimerization. However, none of the introduced KRs afforded simultaneous alteration of methyl and hydroxy configurations in high yield. Therefore, swapping of whole modules might be necessary to achieve such changes in stereochemistry.

  19. Revision of the stereochemistry of elisabethatriene, a putative biosynthetic intermediate of pseudopterosins.

    PubMed

    Nasuda, Masayuki; Ohmori, Miho; Ohyama, Kiyoshi; Fujimoto, Yoshinori

    2012-01-01

    In the past, we have questioned the accuracy of the stereochemistry of elisabethatriene, a putative biosynthetic intermediate of pseudopterosins, in light of the configuration of elisabethatrienol isolated from Pseudopterogorgia elisabethae, which was represented as 1S,4R,9S,11S. We have reinvestigated the stereochemistry of elisabethatriene. Elisabethatriene with the reported 1S,4R,9R,11S configuration was synthesized starting from (-)-isopulegol in its enantiomeric form. The (1)H- and (13)C-NMR data of the synthesized compound differed from those reported for elisabethatriene. In addition to the fact that elisabethatriene is converted into pseudopterosins, this finding has allowed us to propose that elisabethatriene should have the 1S,4R,9S,11S stereochemistry, which is identical to that of elisabethatrienol.

  20. The effects of visual realism on search tasks in mixed reality simulation.

    PubMed

    Lee, Cha; Rincon, Gustavo A; Meyer, Greg; Höllerer, Tobias; Bowman, Doug A

    2013-04-01

    In this paper, we investigate the validity of Mixed Reality (MR) Simulation by conducting an experiment studying the effects of the visual realism of the simulated environment on various search tasks in Augmented Reality (AR). MR Simulation is a practical approach to conducting controlled and repeatable user experiments in MR, including AR. This approach uses a high-fidelity Virtual Reality (VR) display system to simulate a wide range of equal or lower fidelity displays from the MR continuum, for the express purpose of conducting user experiments. For the experiment, we created three virtual models of a real-world location, each with a different perceived level of visual realism. We designed and executed an AR experiment using the real-world location and repeated the experiment within VR using the three virtual models we created. The experiment looked into how fast users could search for both physical and virtual information that was present in the scene. Our experiment demonstrates the usefulness of MR Simulation and provides early evidence for the validity of MR Simulation with respect to AR search tasks performed in immersive VR.

  1. Host-Guest Assembly of a Molecular Reporter with Chiral Cyanohydrins for Assignment of Absolute Stereochemistry.

    PubMed

    Gholami, Hadi; Anyika, Mercy; Zhang, Jun; Vasileiou, Chrysoula; Borhan, Babak

    2016-06-27

    The absolute stereochemistry of cyanohydrins, derived from ketones and aldehydes, is obtained routinely, in a microscale and derivatization-free manner, upon their complexation with Zn-MAPOL, a zincated porphyrin host with a binding pocket comprised of a biphenol core. The host-guest complex leads to observable exciton-coupled circular dichroism (ECCD), the sign of which is easily correlated to the absolute stereochemistry of the bound cyanohydrin. A working model, based on the ECCD signal of cyanohydrins with known configuration, is proposed.

  2. [Dispositional optimism, pessimism and realism in technological potential entrepreneurs].

    PubMed

    López Puga, Jorge; García García, Juan

    2011-11-01

    Optimism has been classically considered a key trait in entrepreneurs' personality but it has been studied from a psychological point of view only in recent years. The main aim of this research is to study the relationship between dispositional optimism, pessimism and realism as a function of the tendency to create technology-based businesses. A sample of undergraduate students (n= 205) filled in an electronic questionnaire containing the Life Orientation Test-Revised after they were classified as potential technological entrepreneurs, potential general entrepreneurs and non-potential entrepreneurs. Our results show that technology-based entrepreneurs are more optimistic than non-potential entrepreneurs, whereas there were no statistical differences in pessimism and realism. The results are interpreted theoretically to define the potential entrepreneur and, from an applied perspective, to design training programmes to support future technological entrepreneurs.

  3. Strong Loophole-Free Test of Local Realism.

    PubMed

    Shalm, Lynden K; Meyer-Scott, Evan; Christensen, Bradley G; Bierhorst, Peter; Wayne, Michael A; Stevens, Martin J; Gerrits, Thomas; Glancy, Scott; Hamel, Deny R; Allman, Michael S; Coakley, Kevin J; Dyer, Shellee D; Hodge, Carson; Lita, Adriana E; Verma, Varun B; Lambrocco, Camilla; Tortorici, Edward; Migdall, Alan L; Zhang, Yanbao; Kumor, Daniel R; Farr, William H; Marsili, Francesco; Shaw, Matthew D; Stern, Jeffrey A; Abellán, Carlos; Amaya, Waldimar; Pruneri, Valerio; Jennewein, Thomas; Mitchell, Morgan W; Kwiat, Paul G; Bienfang, Joshua C; Mirin, Richard P; Knill, Emanuel; Nam, Sae Woo

    2015-12-18

    We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9×10^{-9} for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3×10^{-7}. We therefore reject the hypothesis that local realism governs our experiment.

  4. Adding computationally efficient realism to Monte Carlo turbulence simulation

    NASA Technical Reports Server (NTRS)

    Campbell, C. W.

    1985-01-01

    Frequently in aerospace vehicle flight simulation, random turbulence is generated using the assumption that the craft is small compared to the length scales of turbulence. The turbulence is presumed to vary only along the flight path of the vehicle but not across the vehicle span. The addition of the realism of three-dimensionality is a worthy goal, but any such attempt will not gain acceptance in the simulator community unless it is computationally efficient. A concept for adding three-dimensional realism with a minimum of computational complexity is presented. The concept involves the use of close rational approximations to irrational spectra and cross-spectra so that systems of stable, explicit difference equations can be used to generate the turbulence.

  5. Strong Loophole-Free Test of Local Realism*

    NASA Astrophysics Data System (ADS)

    Shalm, Lynden K.; Meyer-Scott, Evan; Christensen, Bradley G.; Bierhorst, Peter; Wayne, Michael A.; Stevens, Martin J.; Gerrits, Thomas; Glancy, Scott; Hamel, Deny R.; Allman, Michael S.; Coakley, Kevin J.; Dyer, Shellee D.; Hodge, Carson; Lita, Adriana E.; Verma, Varun B.; Lambrocco, Camilla; Tortorici, Edward; Migdall, Alan L.; Zhang, Yanbao; Kumor, Daniel R.; Farr, William H.; Marsili, Francesco; Shaw, Matthew D.; Stern, Jeffrey A.; Abellán, Carlos; Amaya, Waldimar; Pruneri, Valerio; Jennewein, Thomas; Mitchell, Morgan W.; Kwiat, Paul G.; Bienfang, Joshua C.; Mirin, Richard P.; Knill, Emanuel; Nam, Sae Woo

    2015-12-01

    We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9 ×10-9 for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3 ×10-7. We therefore reject the hypothesis that local realism governs our experiment.

  6. Biosynthesis of isoprenoids in Escherichia coli: stereochemistry of the reaction catalyzed by farnesyl diphosphate synthase.

    PubMed

    Leyes, A E; Baker, J A; Poulter, C D

    1999-10-07

    [formula: see text] Farnesyl diphosphate (FPP) synthase from Escherichia coli catalyzes the condensation of isopentenyl diphosphate (IPP) and geranyl diphosphate (GPP) with selective removal of the pro-R hydrogen at C2 of IPP, the same stereochemistry observed for the pig liver, yeast, and avian enzymes.

  7. Using NMR to Probe the Regio- and Stereochemistry of the Hydration of 1-Hexene

    ERIC Educational Resources Information Center

    Saba, Shahrokh; Clarke, Donald D.; Iwanoski, Christa; Lobasso, Thomas

    2010-01-01

    This undergraduate organic laboratory experiment complements previously described and popular experiments on hydration of 1-hexene where students experimentally establish the Markovnikov regioselectivity of alkene hydration. In this experiment, students explore not only the regiochemistry but also the stereochemistry of 1-hexene hydration and…

  8. A Wet-Lab Approach to Stereochemistry Using [superscript 31]P NMR Spectroscopy

    ERIC Educational Resources Information Center

    Fenton, Owen S.; Sculimbrene, Bianca R.

    2011-01-01

    Understanding stereochemistry is an important and difficult task for students to master in organic chemistry. In both introductory and advanced courses, students are encouraged to explore the spatial relationships between molecules, but this exploration is often limited either to the lecture hall or the confines of the library. As such, we sought…

  9. Hexuronic acid stereochemistry determination in chondroitin sulfate glycosaminoglycan oligosaccharides by electron detachment dissociation.

    PubMed

    Leach, Franklin E; Ly, Mellisa; Laremore, Tatiana N; Wolff, Jeremy J; Perlow, Jacob; Linhardt, Robert J; Amster, I Jonathan

    2012-09-01

    Electron detachment dissociation (EDD) has previously provided stereo-specific product ions that allow for the assignment of the acidic C-5stereochemistry in heparan sulfate glycosaminoglycans (GAGs), but application of the same methodology to an epimer pair in the chondroitin sulfate glycoform class does not provide the same result. A series of experiments have been conducted in which glycosaminoglycan precursor ions are independently activated by electron detachment dissociation (EDD), electron induced dissociation (EID), and negative electron transfer dissociation (NETD) to assign the stereochemistry in chondroitin sulfate (CS) epimers and investigate the mechanisms for product ion formation during EDD in CS glycoforms. This approach allows for the assignment of electronic excitation products formed by EID and detachment products to radical pathways in NETD, both of which occur simultaneously during EDD. The uronic acid stereochemistry in electron detachment spectra produces intensity differences when assigned glycosidic and cross-ring cleavages are compared. The variations in the intensities of the doubly deprotonated (0,2)X(3) and Y(3) ions have been shown to be indicative of CS-A/DS composition during the CID of binary mixtures. These ions can provide insight into the uronic acid composition of binary mixtures in EDD, but the relative abundances, although reproducible, are low compared with those in a CID spectrum acquired on an ion trap. The application of principal component analysis (PCA) presents a multivariate approach to determining the uronic acid stereochemistry spectra of these GAGs by taking advantage of the reproducible peak distributions produced by electron detachment.

  10. Implementation and Student Testing of a Web-Based, Student-Centered Stereochemistry Tutorial

    ERIC Educational Resources Information Center

    Burrmann, Nicola J.; Moore, John W.

    2015-01-01

    The implementation of a web-based stereochemistry tutorial, which allows students to select their preferred structural representation and method for making stereochemical comparisons between molecules, is discussed. The tutorial was evaluated by students in three different introductory organic chemistry courses at a large midwestern university.…

  11. Asymptotically optimal data analysis for rejecting local realism

    SciTech Connect

    Zhang, Yanbao; Glancy, Scott; Knill, Emanuel

    2011-12-15

    Reliable experimental demonstrations of violations of local realism are highly desirable for fundamental tests of quantum mechanics. One can quantify the violation witnessed by an experiment in terms of a statistical p value, which can be defined as the maximum probability according to local realism of a violation at least as high as that witnessed. Thus, high violation corresponds to small p value. We propose a prediction-based-ratio (PBR) analysis protocol whose p values are valid even if the prepared quantum state varies arbitrarily and local realistic models can depend on previous measurement settings and outcomes. It is therefore not subject to the memory loophole [J. Barrett et al., Phys. Rev. A 66, 042111 (2002)]. If the prepared state does not vary in time, the p values are asymptotically optimal. For comparison, we consider protocols derived from the number of standard deviations of violation of a Bell inequality and from martingale theory [R. Gill, e-print arXiv:quant-ph/0110137]. We find that the p values of the former can be too small and are therefore not statistically valid, while those derived from the latter are suboptimal. PBR p values do not require a predetermined Bell inequality and can be used to compare results from different tests of local realism independent of experimental details.

  12. The normativity of clinical health care: perspectives on moral realism.

    PubMed

    Nortvedt, Per

    2012-06-01

    The paper argues that a particular version of moral realism constitutes an important basis for ethics in medicine and health care. Moral realism is the position that moral value is a part of the fabric of relational and interpersonal reality. But even though moral values are subject to human interpretations, they are not themselves the sole product of these interpretations. Moral values are not invented but discovered by the subject. Moral realism argues that values are open to perception and experience and that moral subjectivity must be portrayed in how moral values are discovered and perceived by the human subject. Moral values may exist independent of the particular subject's interpretative evaluations as a part of reality. This epistemological point about normativity is particularly significant in medical care and in health care. The clinician perceives moral value in the clinical encounter in a way that is important for competent clinical understanding. Clinical understanding in medical care and health care bears on the encounter with moral values in the direct and embodied relations to patients, with their experiences of illness and their vulnerabilities. Good clinical care is then partly conditioned upon adequate understanding of such moral realities.

  13. Beyond the realism debate: The metaphysics of 'racial' distinctions.

    PubMed

    Lemeire, Olivier

    2016-10-01

    The current metaphysical race debate is very much focused on the realism question whether races exist. In this paper I argue against the importance of this question. Philosophers, biologists and anthropologists expect that answering this question will tell them something substantive about the metaphysics of racial classifications, and will help them to decide whether it is justified to use racial categories in scientific research and public policy. I argue that there are two reasons why these expectations are not fulfilled. First of all, the realism question about race leads to a very broad philosophical debate about the semantics of general terms and the criteria for real kinds, rather than to a debate about the metaphysics of racial categories specifically. Secondly, there is a type of race realism that is so toothless that it is almost completely uninformative about the metaphysics of race. In response to these worries, I argue that the metaphysical race debate should rather be focused on the question in what way and to what extent 'racial' distinctions can ground the epistemic practices of various scientific disciplines. I spell out what I mean by this, and go on to demonstrate that trying to answer this question leads to a more fruitful metaphysical debate.

  14. Critical Realism and Empirical Bioethics: A Methodological Exposition.

    PubMed

    McKeown, Alex

    2015-02-26

    This paper shows how critical realism can be used to integrate empirical data and philosophical analysis within 'empirical bioethics'. The term empirical bioethics, whilst appearing oxymoronic, simply refers to an interdisciplinary approach to the resolution of practical ethical issues within the biological and life sciences, integrating social scientific, empirical data with philosophical analysis. It seeks to achieve a balanced form of ethical deliberation that is both logically rigorous and sensitive to context, to generate normative conclusions that are practically applicable to the problem, challenge, or dilemma. Since it incorporates both philosophical and social scientific components, empirical bioethics is a field that is consistent with the use of critical realism as a research methodology. The integration of philosophical and social scientific approaches to ethics has been beset with difficulties, not least because of the irreducibly normative, rather than descriptive, nature of ethical analysis and the contested relation between fact and value. However, given that facts about states of affairs inform potential courses of action and their consequences, there is a need to overcome these difficulties and successfully integrate data with theory. Previous approaches have been formulated to overcome obstacles in combining philosophical and social scientific perspectives in bioethical analysis; however each has shortcomings. As a mature interdisciplinary approach critical realism is well suited to empirical bioethics, although it has hitherto not been widely used. Here I show how it can be applied to this kind of research and explain how it represents an improvement on previous approaches.

  15. Ways of knowing: realism, non-realism, nominalism and a typology revisited with a counter perspective for nursing science.

    PubMed

    Garrett, Bernard M; Cutting, Roger L

    2015-06-01

    In this paper, we reconsider the context of Barbara Carper's alternative ways of knowing, a prominent discourse in modern nursing theory in North America. We explore this relative to the concepts of realism, non-realism and nominalism, and investigate the philosophical divisions behind the original typology, particularly in relationship to modern scientific enquiry. We examine forms of knowledge relative to realist and nominalist positions and make an argument ad absurdum against relativistic interpretations of knowledge using the example of Borge's Chinese Emporium of Benevolent Knowledge. We propose a contentious postpositivist practical classification for nursing knowledge that demonstrates and supports the idea that knowledge has both individual and subjective components. This classification supports the practical application of nursing knowledge within the paradigm of realist postpositivist science.

  16. On the realism of the re-engineered simple point charge water model

    SciTech Connect

    Chialvo, A.A. |

    1996-04-01

    The realism of the recently proposed high-temperature reparameterization of the simple point charge (SPC) water model [C. D. Berweger, W. F. van Gunsteren, and F. M{umlt u}ller-Plathe, Chem. Phys. Lett. {bold 232}, 429 (1995)] is tested by comparing the simulated microstructure and dielectric properties to the available experimental data. The test indicates that the new parameterization fails dramatically to describe the microstructural and dielectric properties of water at high temperature; it predicts rather strong short-range site{endash}site pair correlations, even stronger than those for water at ambient conditions, and a threefold smaller dielectric constant. Moreover, the resulting microstructure suggests that the high-temperature force-field parameters would predict a twofold higher critical density. The failure of the high-temperature parameterization is analyzed and some suggestions on alternative choices of the target properties for the weak-coupling are discussed. {copyright} {ital 1996 American Institute of Physics.}

  17. Hope Less: How a Healthy Dose of Realism Can Help in the ICU.

    PubMed

    Reis, Elizabeth

    2014-01-01

    The author's father died recently after a sudden heart attack. This essay discusses how the family's experiences in the cardiac intensive care unit surprised her, even though she is a member of the Ethics Committee and the Ethics Consult Team at her local hospital, and how this led her to reconsider the ways in which families and hospital physicians communicate about the process of dying. How should doctors balance their messages of hope and realism when the situation is grim? Important judgment calls needed to be made, yet the family did not fully understand what they needed to know to make good decisions, especially the importance of the timing of their decisions. A conversation early on about what would happen if the patient became physically stable--no matter how impaired--while all options remained on the table might usefully (and mercifully) transform hope at the end.

  18. Stereochemistry of 1,2-elimination and proton-transfer reactions: toward a unified understanding.

    PubMed

    Mohrig, Jerry R

    2013-07-16

    Many mechanistic and stereochemical studies have focused on the breaking of the C-H bond through base-catalyzed elimination reactions. When we began our research, however, chemists knew almost nothing about the stereospecificity of addition-elimination reactions involving conjugated acyclic carbonyl compounds, even though the carbonyl group is a pivotal functional group in organic chemistry. Over the last 25 years, we have studied the addition-elimination reactions of β-substituted acyclic esters, thioesters, and ketones in order to reach a comprehensive understanding of how electronic effects influence their stereochemistry. This Account brings together our understanding of the stereochemistry of 1,2-elimination and proton-transfer reactions, describing how each study has built upon previous work and contributed to our understanding of this field. When we began, chemists thought that anti stereospecificity in base-catalyzed 1,2-elimination reactions occurred via concerted E2 mechanisms, which provide a smooth path for anti elimination. Unexpectedly, we discovered that some E1cBirrev reactions produce the same anti stereospecificity as E2 reactions even though they proceed through diffusionally equilibrated, "free" enolate-anion intermediates. This result calls into question the conventional wisdom that anti stereochemistry must result from a concerted mechanism. While carrying out our research, we developed insights ranging from the role of historical contingency in the evolution of hydratase-dehydratase enzymes to the influence of buffers on the stereochemistry of H/D exchange in D2O. Negative hyperconjugation is the most important concept for understanding our results. This idea provides a unifying view for the largely anti stereochemistry in E1cBirrev elimination reactions and a basis for understanding the stereoelectronic influence of electron-withdrawing β-substituents on proton-transfer reactions.

  19. The German VR Simulation Realism Scale--psychometric construction for virtual reality applications with virtual humans.

    PubMed

    Poeschl, Sandra; Doering, Nicola

    2013-01-01

    Virtual training applications with high levels of immersion or fidelity (for example for social phobia treatment) produce high levels of presence and therefore belong to the most successful Virtual Reality developments. Whereas display and interaction fidelity (as sub-dimensions of immersion) and their influence on presence are well researched, realism of the displayed simulation depends on the specific application and is therefore difficult to measure. We propose to measure simulation realism by using a self-report questionnaire. The German VR Simulation Realism Scale for VR training applications was developed based on a translation of scene realism items from the Witmer-Singer-Presence Questionnaire. Items for realism of virtual humans (for example for social phobia training applications) were supplemented. A sample of N = 151 students rated simulation realism of a Fear of Public Speaking application. Four factors were derived by item- and principle component analysis (Varimax rotation), representing Scene Realism, Audience Behavior, Audience Appearance and Sound Realism. The scale developed can be used as a starting point for future research and measurement of simulation realism for applications including virtual humans.

  20. Time Perception and Depressive Realism: Judgment Type, Psychophysical Functions and Bias

    PubMed Central

    Kornbrot, Diana E.; Msetfi, Rachel M.; Grimwood, Melvyn J.

    2013-01-01

    The effect of mild depression on time estimation and production was investigated. Participants made both magnitude estimation and magnitude production judgments for five time intervals (specified in seconds) from 3 sec to 65 sec. The parameters of the best fitting psychophysical function (power law exponent, intercept, and threshold) were determined individually for each participant in every condition. There were no significant effects of mood (high BDI, low BDI) or judgment (estimation, production) on the mean exponent, n = .98, 95% confidence interval (.96–1.04) or on the threshold. However, the intercept showed a ‘depressive realism’ effect, where high BDI participants had a smaller deviation from accuracy and a smaller difference between estimation and judgment than low BDI participants. Accuracy bias was assessed using three measures of accuracy: difference, defined as psychological time minus physical time, ratio, defined as psychological time divided by physical time, and a new logarithmic accuracy measure defined as ln (ratio). The ln (ratio) measure was shown to have approximately normal residuals when subjected to a mixed ANOVA with mood as a between groups explanatory factor and judgment and time category as repeated measures explanatory factors. The residuals of the other two accuracy measures flagrantly violated normality. The mixed ANOVAs of accuracy also showed a strong depressive realism effect, just like the intercepts of the psychophysical functions. There was also a strong negative correlation between estimation and production judgments. Taken together these findings support a clock model of time estimation, combined with additional cognitive mechanisms to account for the depressive realism effect. The findings also suggest strong methodological recommendations. PMID:23990960

  1. Stereochemistry of the tadalafil diastereoisomers: a critical assessment of vibrational circular dichroism, electronic circular dichroism, and optical rotatory dispersion.

    PubMed

    Qiu, Shi; De Gussem, Ewoud; Tehrani, Kourosch Abbaspour; Sergeyev, Sergey; Bultinck, Patrick; Herrebout, Wouter

    2013-11-14

    The stereochemistry of all four stereoisomers of tadalafil is determined using vibrational circular dichroism (VCD), electronic circular dichroism (ECD), and optical rotatory dispersion (ORD) spectroscopy. By comparing experimentally obtained VCD spectra to computationally simulated ones, the absolute configuration of the enantiomeric pair (6R, 12aR)/(6S, 12aS) can be confidently assigned without prior knowledge of their relative stereochemistry. IR and NMR spectra are used to aid the assignment of the relative stereochemistry. The IR and VCD difference spectra further confirm the assignment of all stereoisomers. ECD and ORD spectra are used to investigate the complementarity of the three chiroptical techniques. VCD spectroscopy itself is found to have the ability to identify diastereoisomers, and simultaneous use of these chiroptical spectroscopic methods and NMR chemical shifts aids in increasing the reliability of stereochemistry assignment of diastereoisomers.

  2. Correction: Absolute stereochemistry and preferred conformations of urate degradation intermediates from computed and experimental circular dichroism spectra.

    PubMed

    Pipolo, Silvio; Percudani, Riccardo; Cammi, Roberto

    2016-04-14

    Correction for 'Absolute stereochemistry and preferred conformations of urate degradation intermediates from computed and experimental circular dichroism spectra' by Silvio Pipolo et al., Org. Biomol. Chem., 2011, 9, 5149-5155.

  3. ADDING REALISM TO NUCLEAR MATERIAL DISSOLVING ANALYSIS

    SciTech Connect

    Williamson, B.

    2011-08-15

    Two new criticality modeling approaches have greatly increased the efficiency of dissolver operations in H-Canyon. The first new approach takes credit for the linear, physical distribution of the mass throughout the entire length of the fuel assembly. This distribution of mass is referred to as the linear density. Crediting the linear density of the fuel bundles results in using lower fissile concentrations, which allows higher masses to be charged to the dissolver. Also, this approach takes credit for the fact that only part of the fissile mass is wetted at a time. There are multiple assemblies stacked on top of each other in a bundle. On average, only 50-75% of the mass (the bottom two or three assemblies) is wetted at a time. This means that only 50-75% (depending on operating level) of the mass is moderated and is contributing to the reactivity of the system. The second new approach takes credit for the progression of the dissolving process. Previously, dissolving analysis looked at a snapshot in time where the same fissile material existed both in the wells and in the bulk solution at the same time. The second new approach models multiple consecutive phases that simulate the fissile material moving from a high concentration in the wells to a low concentration in the bulk solution. This approach is more realistic and allows higher fissile masses to be charged to the dissolver.

  4. Mediated realism and the representation of a health care controversy.

    PubMed

    Petraglia, J

    1994-01-01

    Psychologists have recently identified "situated cognition" as an important issue for educators across disciplines. Accordingly, instructional technologists have been working on ways to make classroom materials more true-to-life and affectively engaging. In this article I review a study designed to investigate the ways in which differing realism conditions (delivered through interactive video) influenced users' understanding of the issue of euthanasia and the case of Dax Cowart. Based on the study's findings, I raise the issue of a possible trade-off between traditional values of objectivity and authenticity.

  5. Magical realism: a cultural intervention for traumatized Hispanic children.

    PubMed

    De Rios, M D

    1997-01-01

    A case study is presented of two Spanish-speaking immigrant children who were run over in an automobile accident and hospitalized, to describe a culturally congruent play-therapy technique. Drawing on the work of Pynoos and Nader, the author argues for an anthropological approach in play therapy to create hyperaroused states for the traumatized child and to use cultural super heroes-what is termed "magical realism." Such an approach can be used with Latin American traumatized children as well as with children from other Third World countries to provide a culturally appropriate intervention to treat the psychological sequelae of trauma.

  6. Faithful test of nonlocal realism with entangled coherent states

    SciTech Connect

    Lee, Chang-Woo; Jeong, Hyunseok; Paternostro, Mauro

    2011-02-15

    We investigate the violation of Leggett's inequality for nonlocal realism using entangled coherent states and various types of local measurements. We prove mathematically the relation between the violation of the Clauser-Horne-Shimony-Holt form of Bell's inequality and Leggett's one when tested by the same resources. For Leggett inequalities, we generalize the nonlocal realistic bound to systems in Hilbert spaces larger than bidimensional ones and introduce an optimization technique that allows one to achieve larger degrees of violation by adjusting the local measurement settings. Our work describes the steps that should be performed to produce a self-consistent generalization of Leggett's original arguments to continuous-variable states.

  7. Extreme Violation of Local Realism in Quantum Hypergraph States.

    PubMed

    Gachechiladze, Mariami; Budroni, Costantino; Gühne, Otfried

    2016-02-19

    Hypergraph states form a family of multiparticle quantum states that generalizes the well-known concept of Greenberger-Horne-Zeilinger states, cluster states, and more broadly graph states. We study the nonlocal properties of quantum hypergraph states. We demonstrate that the correlations in hypergraph states can be used to derive various types of nonlocality proofs, including Hardy-type arguments and Bell inequalities for genuine multiparticle nonlocality. Moreover, we show that hypergraph states allow for an exponentially increasing violation of local realism which is robust against loss of particles. Our results suggest that certain classes of hypergraph states are novel resources for quantum metrology and measurement-based quantum computation.

  8. Improving Realism in Reduced Gravity Simulators

    NASA Technical Reports Server (NTRS)

    Cowley, Matthew; Harvil, Lauren; Clowers, Kurt; Clark, Timothy; Rajulu, Sudhakar

    2010-01-01

    Since man was first determined to walk on the moon, simulating the lunar environment became a priority. Providing an accurate reduced gravity environment is crucial for astronaut training and hardware testing. This presentation will follow the development of reduced gravity simulators to a final comparison of environments between the currently used systems. During the Apollo program era, multiple systems were built and tested, with several NASA centers having their own unique device. These systems ranged from marionette-like suspension devices where the subject laid on his side, to pneumatically driven offloading harnesses, to parabolic flights. However, only token comparisons, if any, were made between systems. Parabolic flight allows the entire body to fall at the same rate, giving an excellent simulation of reduced gravity as far as the biomechanics and physical perceptions are concerned. While the effects are accurate, there is limited workspace, limited time, and high cost associated with these tests. With all mechanical offload systems only the parts of the body that are actively offloaded feel any reduced gravity effects. The rest of the body still feels the full effect of gravity. The Partial Gravity System (Pogo) is the current ground-based offload system used to training and testing at the NASA Johnson Space Center. The Pogo is a pneumatic type system that allows for offloaded motion in the z-axis and free movement in the x-axis, but has limited motion in the y-axis. The pneumatic system itself is limited by cylinder stroke length and response time. The Active Response Gravity Offload System (ARGOS) is a next generation groundbased offload system, currently in development, that is based on modern robotic manufacturing lines. This system is projected to provide more z-axis travel and full freedom in both the x and y-axes. Current characterization tests are underway to determine how the ground-based offloading systems perform, how they compare to parabolic

  9. Stereochemistry and spectroscopic analysis of bis-Betti base derivatives of 2,3-dihydroxynaphthalene.

    PubMed

    Zamani, Mehdi; Shafiee, Mehdi; Keshavarz, Mohammad Hossein

    2016-04-01

    Density functional theory (DFT) was used to study the stereochemistry, thermodynamic stability, and spectra of recently synthesized bis-Betti base derivatives of 2,3-dihydroxynaphthalene obtained through multicomponent reactions of 2,3-dihydroxynaphthalene with aminoisoxazole and benzaldehyde derivatives. The stereochemistry of the products was investigated by theoretically calculating the infrared (IR) and proton nuclear magnetic resonance ((1)H NMR) spectra of the diastereomers and comparing them to the corresponding experimental data. The thermochemical properties of the reactions, including the enthalpy, internal energy, entropy, and Gibbs free energy, were also calculated. The diastereoselectivity of the reactions was estimated from the equilibrium distribution of diastereomers. According to the results, the synthesis of bis-Betti bases is exothermic and accompanied by a decrease in entropy. The energy difference between the diastereomers is quite small, but the Gibbs free energy change for the equilibrium syn <−> anti favors the anti over syn configuration. These results are in good agreement with experimental observations.

  10. Chemical synthesis of the lantibiotic lacticin 481 reveals the importance of lanthionine stereochemistry.

    PubMed

    Knerr, Patrick J; van der Donk, Wilfred A

    2013-05-15

    Lantibiotics are a family of antibacterial peptide natural products characterized by the post-translational installation of the thioether-containing amino acids lanthionine and methyllanthionine. Until recently, only a single naturally occurring stereochemical configuration for each of these cross-links was known. The discovery of lantibiotics with alternative lanthionine and methyllanthionine stereochemistry has prompted an investigation of its importance to biological activity. Here, solid-supported chemical synthesis enabled the total synthesis of the lantibiotic lacticin 481 and analogues containing cross-links with non-native stereochemical configurations. Biological evaluation revealed that these alterations abolished the antibacterial activity in all of the analogues, revealing the critical importance of the enzymatically installed stereochemistry for the biological activity of lacticin 481.

  11. DAG tales: the multiple faces of diacylglycerol--stereochemistry, metabolism, and signaling.

    PubMed

    Eichmann, Thomas Oliver; Lass, Achim

    2015-10-01

    The neutral lipids diacylglycerols (DAGs) are involved in a plethora of metabolic pathways. They function as components of cellular membranes, as building blocks for glycero(phospho)lipids, and as lipid second messengers. Considering their central role in multiple metabolic processes and signaling pathways, cellular DAG levels require a tight regulation to ensure a constant and controlled availability. Interestingly, DAG species are versatile in their chemical structure. Besides the different fatty acid species esterified to the glycerol backbone, DAGs can occur in three different stereo/regioisoforms, each with unique biological properties. Recent scientific advances have revealed that DAG metabolizing enzymes generate and distinguish different DAG isoforms, and that only one DAG isoform holds signaling properties. Herein, we review the current knowledge of DAG stereochemistry and their impact on cellular metabolism and signaling. Further, we describe intracellular DAG turnover and its stereochemistry in a 3-pool model to illustrate the spatial and stereochemical separation and hereby the diversity of cellular DAG metabolism.

  12. Cp* Iridium Complexes Give Catalytic Alkane Hydroxylation with Retention of Stereochemistry

    SciTech Connect

    Zhou, Meng; Schley, Nathan D; Crabtree, Robert H

    2010-08-23

    A series of Cp*Ir complexes can catalyze C-H oxidation, with ceric ammonium nitrate as the terminal oxidant and water as the source of oxygen. Remarkably the hydroxylation of cis-decalin and 1,4-dimethylcyclohexane proceeds with retention of stereochemistry. With H2O18, cis-decalin oxidation gave 18O incorporation into the product cis-decalol.

  13. Synthesis and dynamic stereochemistry of 4-aryl-thiomorpholine-3,5-dione derivatives

    NASA Astrophysics Data System (ADS)

    Szawkało, Joanna; Maurin, Jan K.; Pluciński, Franciszek; Czarnocki, Zbigniew

    2015-01-01

    A series of new N-aryl-substituted thiomorpholine-3,5-diones were synthesized. Crystal structures of seven compounds were established on the basis of X-ray crystallography. Stable at room temperature diastereomers were detected for (2-phenyl)-substituted derivatives using 1H NMR. The dynamic stereochemistry of compound 36 was studied with variable-temperature 1H NMR and the mechanism of diastereomers interconversion was proposed on the basis of quantum chemical calculations.

  14. Relative Stereochemistry and Absolute Configuration of Farinosin, a Eudesmanolide From Encelia farinosa.

    PubMed

    Ortega, Alfredo R; Sánchez-Castellanos, Mariano; Pérez-Hernández, Nury; Robles-Zepeda, Ramón E; Joseph-Nathan, Pedro; Quijano, Leovigildo

    2016-05-01

    The naturally occurring eudesmanolide farinosin () is now fully characterized for the first time despite its original isolation almost half a century ago. The early assumed relative stereochemistry and absolute configuration were confirmed by vibrational circular dichroism together with evaluation of the Hooft X-ray parameters. The molecular conformation is very similar in the gas stage and in the solid state. Chirality 28:415-419, 2016. © 2016 Wiley Periodicals, Inc.

  15. Stereochemistry of coordination compounds. From alfred werner to the 21st century.

    PubMed

    von Zelewsky, Alex

    2014-01-01

    As a contribution to the scientific symposium, November 22nd, 2013, commemorating the Nobel Prize awarded to Alfred Werner in 1913, a presentation of the development of stereochemistry of coordination compounds during the past 120 years was given. Stereochemistry was fundamental to Werner's theory of coordination compounds. After Werner's death in 1919, stereochemistry in this field did not progress much further for almost 20 years, but then developed continuously. It was realized that stereochemical features of elements showing coordination numbers larger than four are responsible for an almost unlimited number of stereochemical possibilities, thus opening a molecular world of new structures. In the beginning of the 21st century, interest in the field rose again considerably, mainly due to the potential of stereoselective catalysis, and the self-assembly of supramolecular structures. An end of these developments is not in sight. Here an abbreviated version of the lecture is given. A PowerPoint(®) file, or a video of the presentation, can be downloaded.

  16. Enhancing Realism of Wet Surfaces in Temporal Bone Surgical Simulation

    PubMed Central

    Kerwin, Thomas; Shen, Han-Wei; Stredney, Don

    2009-01-01

    We present techniques to improve visual realism in an interactive surgical simulation application: a mastoidectomy simulator that offers a training environment for medical residents as a complement to using a cadaver. As well as displaying the mastoid bone through volume rendering, the simulation allows users to experience haptic feedback and appropriate sound cues while controlling a virtual bone drill and suction/irrigation device. The techniques employed to improve realism consist of a fluid simulator and a shading model. The former allows for deformable boundaries based on volumetric bone data, while the latter gives a wet look to the rendered bone to emulate more closely the appearance of the bone in a surgical environment. The fluid rendering includes bleeding effects, meniscus rendering, and refraction. We incorporate a planar computational fluid dynamics simulation into our three-dimensional rendering to effect realistic blood diffusion. Maintaining real-time performance while drilling away bone in the simulation is critical for engagement with the system. PMID:19590102

  17. Using critical realism as a framework in pharmacy education and social pharmacy research.

    PubMed

    Oltmann, Carmen; Boughey, Chrissie

    2012-01-01

    This article challenges the idea that positivism is capable of representing the complexity of social pharmacy and pharmacy education. It is argued that critical realism provides a framework that allows researchers to look at the nature of reality and at mechanisms that produce, or have the tendency to produce, events and experiences of those events. Critical realism is a framework, not a method. It allows researchers to make observations about phenomena and explain the relationships and connections involved. The researcher has to look for mechanisms and structures that could explain why the phenomena, the connections, and the relationships exist (or do not) and then try to show that these mechanisms do exist. This article first contextualizes critical realism, then briefly describes it, and lastly exemplifies the use of critical realism in a discussion of a research project conducted in pharmacy education. Critical realism may be particularly useful in interdisciplinary research, for example, where practitioners and researchers are working together in a social pharmacy or pharmacy education setting. Critical realism requires the practitioners and the researchers to question and make known their assumptions about their own realities and to think of a complex problem or phenomenon in terms of a stratified reality, generative mechanisms, and tendencies. Critical realism may make research more rigorous and also allow researchers to conceive of a greater breadth of research designs for their work.

  18. Get real: how current behavior influences perceptions of realism and behavioral intent for public service announcements.

    PubMed

    Nelson, Michelle R; Zhu, Xuan; Li, Yingying; Fiese, Barbara; Koester, Brenda

    2015-01-01

    This research examined how realism and current behavior influence message reception and processing for public service announcements (PSAs) designed to help parents with meal planning. Findings from 19 in-depth interviews revealed that the perceived realism of the message, the similarity, and the wishful identification with informants' lives influenced message acceptance, in line with the Message Interpretation Process (MIP) model. Results of an online survey with mothers show that realism matters more for those individuals who already engage in the featured behavior. In line with theory, "experts" (meal planners) show increased behavioral intent of the featured behaviors when viewing the more realistic PSA.

  19. Critical realism: a philosophical framework for the study of gender and mental health.

    PubMed

    Bergin, Michael; Wells, John S G; Owen, Sara

    2008-07-01

    This paper explores gender and mental health with particular reference to the emerging philosophical field of critical realism. This philosophy suggests a shared ontology and epistemology for the natural and social sciences. Until recently, most of the debate surrounding gender and mental health has been guided either implicitly or explicitly within a positivist or constructivist philosophy. With this in mind, key areas of critical realism are explored in relation to gender and mental health, and contrasted with the positions of positivism and constructivism. It is argued that critical realism offers an alternative philosophical framework for the exploration of gender issues within mental health care.

  20. Modeling Heliospheric Plasma Turbulence: A Critique of the Effects of Completeness, Realism and Size

    NASA Astrophysics Data System (ADS)

    Matthaeus, W. H.; Wan, M.; Parashar, T.; Shay, M. A.

    2015-12-01

    With the Solar Probe and Solar Orbiter missions approaching, and the highly capable instruments of MMS already in orbit, there is an upwelling of interest in understanding plasma turbulence and related effects at kinetic scales. Accordingly a variety of methods have been employed to study kinetic turbulence and in particular dissipation and cascade processes and their effects on protons, electrons and minor ions. Here we discuss the influence of system size, and the completeness and realism of the several kinetic physics models that are employed. One important issue is whether coherent structures such as current sheets can be properly represented and evolved in smaller systems; this is particular important when turbulence is intermittent and non-self similar, so that couplings become nonlocal in scale. Another factor is resolution, both spatial and statistical - what are the effects of counting statistics in PIC and velocity filamentation in Vlasov models? Also discussed is the efficacy and strategic use of models with reduced physics and/or dimensionality - hybrid, Reduced MHD and gyrokinetics, for example. It is suggested, using several example problems, how the cross comparison of models in the context of a framework such as Turbochallenge may have wide ranging conceptual impact.

  1. Design of interactive health drama built on social realism.

    PubMed

    Graspemo, Gabriella; Hassling, Linda; Nordfeldt, Sam; Eriksson, Hendrik; Timpka, Toomas

    2004-01-01

    There are many psychosocial aspects of chronic diseases, such as diabetes. Educational multimedia can support patients with chronic diseases and their families by communicating narratives based on social realism. The production of such socio-realistic interactive health dramas requires systematic methods, especially for the identification of significant stories. The aim of this study is to explore the use of self-documentary video in the design of an Interactive Health Drama environment to support diabetic adolescents and their families. In particular, the potential of the self-documentary video for story development in combination with qualitative interviews were explored. The proposed approach, when further developed, is intended to enable all types of chronic disease patients to work with their specific psychosocial problems in a supportive and stimulating environment adapted to their personality and preferences.

  2. Processing Digital Imagery to Enhance Perceptions of Realism

    NASA Technical Reports Server (NTRS)

    Woodell, Glenn A.; Jobson, Daniel J.; Rahman, Zia-ur

    2003-01-01

    Multi-scale retinex with color restoration (MSRCR) is a method of processing digital image data based on Edwin Land s retinex (retina + cortex) theory of human color vision. An outgrowth of basic scientific research and its application to NASA s remote-sensing mission, MSRCR is embodied in a general-purpose algorithm that greatly improves the perception of visual realism and the quantity and quality of perceived information in a digitized image. In addition, the MSRCR algorithm includes provisions for automatic corrections to accelerate and facilitate what could otherwise be a tedious image-editing process. The MSRCR algorithm has been, and is expected to continue to be, the basis for development of commercial image-enhancement software designed to extend and refine its capabilities for diverse applications.

  3. A Measure of Psychological Realism on a Visual Simulator

    NASA Technical Reports Server (NTRS)

    Palmer, Everett; Petitt, John

    1977-01-01

    A FUNDAMENTAL question of simulation technology is how to determine if an aircraft simulation is creating the proper psychological space necessary to assess manned-system performance. The standard approach to this problem for visual simulators is to measure how well pilots can make approaches and landings on the simulator. Experiments of this type generally show that simulator performance is worse than actual landing performance and that there is an excessive amount of training required to reach acceptable performance. Unfortunately, in these experiments it is difficult to sort out the inadequacies of the visual subsystem from possible inadequacies in other simulator subsystems, such as the motion subsystem. This synoptic presents the results from one of a series of five experiments which attempted to provide direct measures of the psychological realism on a computer graphics night visual flight attachment. These experiments used experimental procedures and methodologies that psychologists have developed in their attempts to determine how people perceived visual space in the real world.

  4. Sesquiterpene lactone stereochemistry influences herbivore resistance and plant fitness in the field

    PubMed Central

    Ahern, Jeffrey R.; Whitney, Kenneth D.

    2014-01-01

    Background and Aims Stereochemical variation is widely known to influence the bioactivity of compounds in the context of pharmacology and pesticide science, but our understanding of its importance in mediating plant–herbivore interactions is limited, particularly in field settings. Similarly, sesquiterpene lactones are a broadly distributed class of putative defensive compounds, but little is known about their activities in the field. Methods Natural variation in sesquiterpene lactones of the common cocklebur, Xanthium strumarium (Asteraceae), was used in conjunction with a series of common garden experiments to examine relationships between stereochemical variation, herbivore damage and plant fitness. Key Results The stereochemistry of sesquiterpene lactone ring junctions helped to explain variation in plant herbivore resistance. Plants producing cis-fused sesquiterpene lactones experienced significantly higher damage than plants producing trans-fused sesquiterpene lactones. Experiments manipulating herbivore damage above and below ambient levels found that herbivore damage was negatively correlated with plant fitness. This pattern translated into significant fitness differences between chemotypes under ambient levels of herbivore attack, but not when attack was experimentally reduced via pesticide. Conclusions To our knowledge, this work represents only the second study to examine sesquiterpene lactones as defensive compounds in the field, the first to document herbivore-mediated natural selection on sesquiterpene lactone variation and the first to investigate the ecological significance of the stereochemistry of the lactone ring junction. The results indicate that subtle differences in stereochemistry may be a major determinant of the protective role of secondary metabolites and thus of plant fitness. As stereochemical variation is widespread in many groups of secondary metabolites, these findings suggest the possibility of dynamic evolutionary histories

  5. Reducing consistency in human realism increases the uncanny valley effect; increasing category uncertainty does not.

    PubMed

    MacDorman, Karl F; Chattopadhyay, Debaleena

    2016-01-01

    Human replicas may elicit unintended cold, eerie feelings in viewers, an effect known as the uncanny valley. Masahiro Mori, who proposed the effect in 1970, attributed it to inconsistencies in the replica's realism with some of its features perceived as human and others as nonhuman. This study aims to determine whether reducing realism consistency in visual features increases the uncanny valley effect. In three rounds of experiments, 548 participants categorized and rated humans, animals, and objects that varied from computer animated to real. Two sets of features were manipulated to reduce realism consistency. (For humans, the sets were eyes-eyelashes-mouth and skin-nose-eyebrows.) Reducing realism consistency caused humans and animals, but not objects, to appear eerier and colder. However, the predictions of a competing theory, proposed by Ernst Jentsch in 1906, were not supported: The most ambiguous representations-those eliciting the greatest category uncertainty-were neither the eeriest nor the coldest.

  6. Impact of Absolute Stereochemistry on the Antiangiogenic and Antifungal Activities of Itraconazole

    PubMed Central

    2010-01-01

    Itraconazole is used clinically as an antifungal agent and has recently been shown to possess antiangiogenic acitivity. Itraconazole has three chiral centers that give rise to eight stereoisomers. The complete role of stereochemistry in the two activities of itraconazole, however, has not been addressed adequately. For the first time, all eight stereoisomers of itraconazole (1a−h) have been synthesized and evaluated for activity against human endothelial cell proliferation and for antifungal activity against five fungal strains. Distinct antiangiogenic and antifungal activity profiles of the trans stereoisomers, especially 1e and 1f, suggest different molecular mechanisms underlying the antiangiogenic and antifungal activities of itraconazole. PMID:21892383

  7. Through-space (19) F-(15) N couplings for the assignment of stereochemistry in flubenzimine.

    PubMed

    Ghiviriga, Ion; Rubinski, Miles A; Dolbier, William R

    2016-07-01

    Through-space (19) F-(15) N couplings revealed the configuration of flubenzimine, with the CF3 group on N4 pointing towards the lone pair of N5. The (19) F-(15) N coupling constants were measured at natural abundance using a spin-state selective indirect-detection pulse sequence. As (15) N-labelled proteins are routinely synthesized for NMR studies, through-space (19) F-(15) N couplings have the potential to probe the stereochemistry of these proteins by (19) F labelling of some amino acids or can reveal the site of docking of fluorine-containing drugs. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Naïve realism: folk fallacies in the design and use of visual displays.

    PubMed

    Smallman, Harvey S; Cook, Maia B

    2011-07-01

    Often implicit in visual display design and development is a gold standard of photorealism. By approximating direct perception, photorealism appeals to users and designers by being both attractive and apparently effortless. The vexing result from numerous performance evaluations, though, is that increasing realism often impairs performance. Smallman and St. John (2005) labeled misplaced faith in realistic information display Naïve Realism and theorized it resulted from a triplet of folk fallacies about perception. Here, we illustrate issues associated with the wider trend towards realism by focusing on a specific current trend for high-fidelity perspective view (3D) geospatial displays. In two experiments, we validated Naïve Realism for different terrain understanding tasks, explored whether certain individuals are particularly prone to Naïve Realism, and determined the ability of task feedback to mitigate Naïve Realism. Performance was measured for laying and judging a concealed route across realistic terrain shown in different display formats. Task feedback was either implicit, in Experiment 1, or explicit in Experiment 2. Prospective and retrospective intuitions about the best display formats for the tasks were recorded and then related to task performance and participant spatial ability. Participants generally intuited they would perform tasks better with more realism than they actually required. For example, counter to intuitions, lowering fidelity of the terrain display revealed the gross scene layout needed to lay a well-concealed route. Individuals of high spatial ability calibrated their intuitions with only implicit task feedback, whereas those of low spatial ability required salient, explicit feedback to calibrate their intuitions about display realism. Results are discussed in the wider context of applying perceptual science to display design, and combating folk fallacies.

  9. The use of J-coupling as a sole criterion to assign the total absolute stereochemistry of new pyrrolidinone class synthetic analogs, derived from S-pyroglutamic acid

    NASA Astrophysics Data System (ADS)

    Kellici, Tahsin F.; Ntountaniotis, Dimitrios; Vanioti, Marianna; Golic Grdadolnik, Simona; Simcic, Mihael; Michas, Georgios; Moutevelis-Minakakis, Panagiota; Mavromoustakos, Thomas

    2017-02-01

    During the synthesis of new pyrrolidinone analogs possessing biological activity it is intriguing to assign their absolute stereochemistry as it is well known that drug potency is influenced by the stereochemistry. The combination of J-coupling information with theoretical results was used in order to establish their total stereochemistry when the chiral center of the starting material has known absolute stereochemistry. The J-coupling can be used as a sole criterion for novel synthetic analogs to identify the right stereochemistry. This approach is extremely useful especially in the case of analogs whose 2D NOESY spectra cannot provide this information. Few synthetic examples are given to prove the significance of this approach.

  10. Effect of stereochemistry, chain length and sequence pattern on antimicrobial properties of short synthetic β-sheet forming peptide amphiphiles.

    PubMed

    Ong, Zhan Yuin; Cheng, Junchi; Huang, Yuan; Xu, Kaijin; Ji, Zhongkang; Fan, Weimin; Yang, Yi Yan

    2014-01-01

    In the face of mounting global antibiotics resistance, the identification and development of membrane-active antimicrobial peptides (AMPs) as an alternative class of antimicrobial agent have gained significant attention. The physical perturbation and disruption of microbial membranes by the AMPs have been proposed to be an effective means to overcome conventional mechanisms of drug resistance. Recently, we have reported the design of a series of short synthetic β-sheet folding peptide amphiphiles comprised of recurring (X1Y1X2Y2)n-NH2 sequences where X: hydrophobic amino acids, Y: cationic amino acids and n: number of repeat units. In efforts to investigate the effects of key parameters including stereochemistry, chain length and sequence pattern on antimicrobial effects, systematic d-amino acid substitutions of the lead peptides (IRIK)2-NH2 (IK8-all L) and (IRVK)3-NH2 (IK12-all L) were performed. It was found that the corresponding D-enantiomers exhibited stronger antimicrobial activities with minimal or no change in hemolytic activities, hence translating very high selectivity indices of 407.0 and >9.8 for IK8-all D and IK12-all D respectively. IK8-all D was also demonstrated to be stable to degradation by broad spectrum proteases trypsin and proteinase K. The membrane disrupting bactericidal properties of IK8-all D effectively prevented drug resistance development and inhibited the growth of various clinically isolated MRSA, VRE, Acinetobacter baumanni, Pseudomonas aeruginosa, Cryptococcus. neoformans and Mycobacterium tuberculosis. Significant reduction in intracellular bacteria counts was also observed following treatment with IK8-all D in the Staphylococcus. aureus infected mouse macrophage cell line RAW264.7 (P < 0.01). These results suggest that the d-amino acids substituted β-sheet forming peptide IK8-all D with its enhanced antimicrobial activities and improved protease stability, is a promising therapeutic candidate with potential to combat

  11. Stereochemistry at the forefront in the design and discovery of novel anti-tuberculosis agents.

    PubMed

    Huang, Qingqing; He, Rong; Kozikowski, Alan P

    2011-01-01

    Today, 75% of new drugs introduced to the market are single enantiomers and new techniques in asymmetric synthesis and chiral separation expedites chiral drug discovery and development worldwide. The enantiomers of a chiral drug present unique chemical and pharmacological behaviors in a chiral environment, such as the human body, in which the stereochemistry of chiral drugs determines their pharmacokinetic, pharmacodynamic, and toxicological actions. Thus, it is imperative that only the pure and therapeutically active isomer be prepared and marketed. Tuberculosis (TB), a highly contagious and airborne disease that is caused by infection with Mycobacterium tuberculosis (Mtb), currently represents one of the most threatening health problems globally. The emergence of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB), as well as HIV co-infection along with a lengthy treatment regimen, highlights an urgent need for the development of new anti-TB agents. Currently, new chiral anti-TB agents are being developed from some well-known anti-TB agents, high throughput screening (HTS) hits, and natural products. This review will focus on the reported chiral anti-TB agents together with the clinical importance of their chirality and stereochemistry.

  12. Stereochemistry and conformation of skyllamycin, a non-ribosomally synthesized peptide from Streptomyces sp. Acta 2897.

    PubMed

    Schubert, Vivien; Di Meo, Florent; Saaidi, Pierre-Loïc; Bartoschek, Stefan; Fiedler, Hans-Peter; Trouillas, Patrick; Süssmuth, Roderich D

    2014-04-22

    Skyllamycin is a non-ribosomally synthesized cyclic depsipeptide from Streptomyces sp. Acta 2897 that inhibits PDGF-signaling. The peptide scaffold contains an N-terminal cinnamoyl moiety, a β-methylation of aspartic acid, three β-hydroxylated amino acids and one rarely occurring α-hydroxy glycine. With the exception of α-hydroxy glycine, the stereochemistry of the amino acids was assigned by comparison to synthetic reference amino acids applying chiral GC-MS and Marfey-HPLC analysis. The stereochemistry of α-hydroxy glycine, which is unstable under basic and acidic conditions, was determined by conformational analysis, employing a combination of data from NOESY-NMR spectroscopy, simulated annealing and free MD simulations. The simulation procedures were applied for both R- and S-configured α-hydroxy glycine of the skyllamycin structure and compared to the NOESY data. Both methods, simulated annealing and free MD simulations independently support S-configured α-hydroxy glycine thus enabling the assignment of all stereocenters in the structure of skyllamycin and devising the role of two-component flavin dependent monooxygenase (Sky39) as S-selective.

  13. Probing the stereochemistry of successive sulfoxidation of the insecticide fenamiphos in soils.

    PubMed

    Cai, Xiyun; Xiong, Weina; Xia, Tingting; Chen, Jingwen

    2014-10-07

    Successive sulfoxidation is widely recognized as a general characteristic of the metabolism of chiral or prochiral thioethers, producing sulfoxides, and sulfones. However, information related to the stereochemistry of this process in soils is rare. In this study, the biotic transformation of the insecticide fenamiphos (a model thioether) was followed over two months in three soils, through separate incubations with fenamiphos parent, the sulfoxide intermediate (FSO), the sulfone intermediate (FSO2), and their respective stereoisomers. The results showed that the successive sulfoxidation involved oxidation of fenamiphos to FSO and subsequently to FSO2 as well as diastereomerization/enantiomerization of FSO, all of which were primarily biotic and stereoselective. The concomitant hydrolysis of fenamiphos, FSO, and FSO2 to phenols that occurred at lower rates was biotically favorable, but not stereoselective. The stereochemistry of this successive sulfoxidation transferred principally through two parallel systems, R(+)-fenamiphos → SRPR(+)-/SSPR(-)-FSO → R(+)-FSO2 and S(-)-fenamiphos → SRPS(+)-/SSPS(-)-FSO → S(-)-FSO2, between which unidirectional intersystem crossing occurred at FSO via isomeric conversions and created a system of S(-)-fenamiphos → SRPR(+)-/SSPR(-)-FSO → R(+)-FSO2. This pattern accounts for the enrichment of the intermediates SSPR(-)-/SSPS(-)-FSO and R(+)-FSO2 that are toxicologically close to the highly toxic S(-)-fenamiphos, associated with soil application of fenamiphos. Selective formation/depletion of these intermediate stereoisomers leads to dramatic variations in the ecotoxicological effects of the thioether insecticide.

  14. How stereochemistry influences the taste of wine: Isolation, characterization and sensory evaluation of lyoniresinol stereoisomers.

    PubMed

    Cretin, Blandine N; Sallembien, Quentin; Sindt, Lauriane; Daugey, Nicolas; Buffeteau, Thierry; Waffo-Teguo, Pierre; Dubourdieu, Denis; Marchal, Axel

    2015-08-12

    Wine expresses its beauty by sending a sensory message to the taster through molecules coming from grapes, yeast metabolism or oak wood. Among the compounds released during barrel aging, lyoniresinol has been recently reported as a relevant contributor to wine bitterness. As this lignan contains three stereogenic carbons, this work aimed at investigating the influence of stereochemistry on wine taste by combining analytical and sensorial techniques. First, an oak wood extract was screened by Liquid Chromatography-High Resolution Mass Spectrometry to target isomers separable in a symmetric environment and a diastereoisomer called epi-lyoniresinol was isolated for the first time. Then, an original racemic resolution based on natural xylose-derivatives was carried out to obtain lyoniresinol enantiomers. Chiroptical spectroscopic measurements associated with theoretical calculations allowed the unambiguous determination of their absolute configuration. The taste properties of all these stereoisomers revealed that only one lyoniresinol enantiomer is strongly bitter whereas the other one is tasteless and the diastereoisomer is slightly sweet. The presence of these three compounds was established in an oaked Bordeaux wine by chiral and non-chiral chromatography, suggesting the significant influence of stereochemistry on wine taste.

  15. Mediating role of activity level in the depressive realism effect.

    PubMed

    Blanco, Fernando; Matute, Helena; A Vadillo, Miguel

    2012-01-01

    Several classic studies have concluded that the accuracy of identifying uncontrollable situations depends heavily on depressive mood. Nondepressed participants tend to exhibit an optimistic illusion of control, whereas depressed participants tend to better detect a lack of control. Recently, we suggested that the different activity levels (measured as the probability of responding during a contingency learning task) exhibited by depressed and nondepressed individuals is partly responsible for this effect. The two studies presented in this paper provide further support for this mediational hypothesis, in which mood is the distal cause of the illusion of control operating through activity level, the proximal cause. In Study 1, the probability of responding, P(R), was found to be a mediator variable between the depressive symptoms and the judgments of control. In Study 2, we intervened directly on the mediator variable: The P(R) for both depressed and nondepressed participants was manipulated through instructions. Our results confirm that P(R) manipulation produced differences in the participants' perceptions of uncontrollability. Importantly, the intervention on the mediator variable cancelled the effect of the distal cause; the participants' judgments of control were no longer mood dependent when the P(R) was manipulated. This result supports the hypothesis that the so-called depressive realism effect is actually mediated by the probability of responding.

  16. 'Diverse epistemologies', truth and archaeology: in defence of realism.

    PubMed

    Horsthemke, Kai

    2011-06-01

    In a recent journal article, as well as in a recent book chapter, in which she critiques my position on 'indigenous knowledge', Lesley Green of the Department of Social Anthropology at the University of Cape Town argues that 'diverse epistemologies ought to be evaluated not on their capacity to express a strict realism but on their ability to advance understanding'. In order to examine the implications of Green's arguments, and of Nelson Goodman and Catherine Elgin's work in this regard, I apply them to a well-known controversy between Native American (or First Nations) creationism and archaeology. I argue that issues in social justice should be distinguished from issues in epistemology. Moreover, in tightening in this paper the link between knowledge and truth, I attempt to defend science as a 'privileged way of seeing the world'. The analysis of truth, and of related concepts like reality and 'the way the world is', will assume a central role here. I contend that, ultimately, the only coherent and consistent position is a realist view of the pertinent issues and ideas.

  17. Nanoscale amphiphilic macromolecules with variable lipophilicity and stereochemistry modulate inhibition of oxidized low-density lipoprotein uptake.

    PubMed

    Poree, Dawanne E; Zablocki, Kyle; Faig, Allison; Moghe, Prabhas V; Uhrich, Kathryn E

    2013-08-12

    Amphiphilic macromolecules (AMs) based on carbohydrate domains functionalized with poly(ethylene glycol) can inhibit the uptake of oxidized low density lipoprotein (oxLDL) and counteract foam cell formation, a key characteristic of early atherogenesis. To investigate the influence of lipophilicity and stereochemistry on the AMs' physicochemical and biological properties, mucic acid-based AMs bearing four aliphatic chains (2a) and tartaric acid-based AMs bearing two (2b and 2l) and four aliphatic chains (2g and 2k) were synthesized and evaluated. Solution aggregation studies suggested that both the number of hydrophobic arms and the length of the hydrophobic domain impact AM micelle sizes, whereas stereochemistry impacts micelle stability. 2l, the meso analogue of 2b, elicited the highest reported oxLDL uptake inhibition values (89%), highlighting the crucial effect of stereochemistry on biological properties. This study suggests that stereochemistry plays a critical role in modulating oxLDL uptake and must be considered when designing biomaterials for potential cardiovascular therapies.

  18. Stereochemistry analysis and comparison of two C(3)-alkyl substituted cyclohexonedicarboxylates with their C(3)-aryl substituted analogues

    NASA Astrophysics Data System (ADS)

    Chen, Chao-Yue; Wang, Qi; Zhu, Bing-Long; Zhao, Wen-Jie; Hu, Jin-Song

    2016-03-01

    Two representative C(3)-alkyl substituted cyclohexonedicarboxylates (4a and 4b) were synthesized and their conformational features were investigated by single crystal X-ray crystallography for the first time. These stereochemistry results of 4a and 4b were compared with those obtained from the earlier research of C(3)-aryl substituted analogues (1-3).

  19. Structures, Reactions, and Mechanisms: Stereochemistry in the Broadest Sense at the 51st Bürgenstock Conference.

    PubMed

    Fleischer, Ivana

    2016-07-18

    Tradition and innovation: The 51st Bürgenstock Conference on Stereochemistry took place from May 1-6, 2016 and offered its usual mixture of impressive science and superb discussions in a wonderful atmosphere. In the Meeting Review, Ivana Fleischer outlines the program.

  20. Physics.

    ERIC Educational Resources Information Center

    Bromley, D. Allan

    1980-01-01

    The author presents the argument that the past few years, in terms of new discoveries, insights, and questions raised, have been among the most productive in the history of physics. Selected for discussion are some of the most important new developments in physics research. (Author/SA)

  1. Topological Stereochemistry.

    DTIC Science & Technology

    1988-01-29

    Perry, A.E.; Richards, R.M.; Homan, T.C.; Haltiwanger, R.C. "The THYME Polyethers: An Approach to the Synthesis of a Molecular Knotted Ring...4. Walba, D.M.; Richards, R.M.; Hermsmeier, M.; Haltiwanger, R.C. "Conformational Properties of the THYME Polyethers: The Bis- THYME Cylinder-a 3...strips, linked rings, and knotted rings, using the tetrahydroxymethyl- ethylene ( THYME ) fused crown ether strategy illustrated by our synthesis of the

  2. Carbohydrate Stereochemistry.

    ERIC Educational Resources Information Center

    Shallenberger, Robert S.; Wienen, Wanda J.

    1989-01-01

    Treats the development of general stereochemical principles in historical fashion. Discusses work by Pasteur, van't Hoff, and Le Bel. Considers sugars by configuration, anomeric forms, ring forms, and conformational isomers. Presents numerous diagrams and thorough explanations. (MVL)

  3. The effect of stereochemistry on the biological activity of natural phytotoxins, fungicides, insecticides and herbicides.

    PubMed

    Evidente, Antonio; Cimmino, Alessio; Andolfi, Anna

    2013-02-01

    Phytotoxins are secondary microbial metabolites that play an essential role in the development of disease symptoms induced by fungi on host plants. Although phytotoxins can cause extensive-and in some cases devastating-damage to agricultural crops, they can also represent an important tool to develop natural herbicides when produced by fungi and plants to inhibit the growth and spread of weeds. An alternative strategy to biologically control parasitic plants is based on the use of plant and fungal metabolites, which stimulate seed germination in the absence of the host plant. Nontoxigenic fungi also produce bioactive metabolites with potential fungicide and insecticide activity, and could be applied for crop protection. All these metabolites represent important tools to develop eco-friendly pesticides. This review deals with the relationships between the biological activity of some phytotoxins, seed germination stimulants, fungicides and insecticides, and their stereochemistry.

  4. Antibacterial adhesion of borneol-based polymer via surface chiral stereochemistry.

    PubMed

    Luo, Lingqiong; Li, Guofeng; Luan, Di; Yuan, Qipeng; Wei, Yen; Wang, Xing

    2014-01-01

    During its adhesion on external surfaces, a cell exhibits obvious inclination to different molecular chirality, which encourages us to develop a new type of antibacterial material catering to the "chiral taste" of bacteria. On the basis of the natural product borneol (a camphane-type bicyclic monoterpene), a series of borneol-based polymer, polyborneolacrylate (PBA), was successfully prepared and showed superior antibacterial adhesion properties resulting from the borneol isomers on material surface. The results of this study reveal that bacteria simply dislike this type of stubborn surface of PBA, and the PBA surface stereochemistry contributes to the interfacial antibacterial activities. The PBA polymers were evaluated as noncytotoxic and can be simply synthesized, demonstrating their great potential for biomedical applications.

  5. Total Syntheses of (+)-Grandilodine C and (+)-Lapidilectine B and Determination of their Absolute Stereochemistry.

    PubMed

    Nakajima, Masaya; Arai, Shigeru; Nishida, Atsushi

    2016-03-01

    Enantioselective total syntheses of the Kopsia alkaloids (+)-grandilodine C and (+)-lapidilectine B were accomplished. A key intermediate, spirodiketone, was synthesized in 3 steps and converted into the chiral enone by enantioselective deprotonation followed by oxidation with up to 76 % ee. Lactone formation was achieved through stereoselective vinylation followed by allylation and ozonolysis. The total synthesis of (+)-grandilodine C was achieved by palladium-catalyzed intramolecular allylic amination and ring-closing metathesis to give 8- and 5-membered heterocycles, respectively. Selective reduction of a lactam carbonyl gave (+)-lapidilectine B. The absolute stereochemistry of both natural products was thereby confirmed. These syntheses enable the scalable preparation of the above alkaloids for biological studies.

  6. Enantiomeric HPLC resolution and absolute stereochemistry assignment of a new poligamain derivative.

    PubMed

    Pistolozzi, M; Royo, V; Pereira, A C; Silva, M L A; Silva, R; Cunha, W R; Vaconcelos, K; Cass, Q B; Martins, C H G; Bastos, J K; Varchi, G; Guerrini, A; Bertucci, C

    2013-03-05

    A new aryltetralin lignan derivative, 1, was obtained by reacting dimethyl succinate and piperonal, furnishing the lactone 4-(3',4'-methylenedioxybenzyl)-4,5-dihydro-2(3H)-furanone, which was reacted once again with piperonal and LDA to give the dibenzylbutirolactone 7-hydroxyhinokinin. The cyclization of 7-hydroxyhinokinin into polygamain occurred in the presence of trifluoroacetic acid. The reduction of the furanic ring of polygamain was done by its reaction with DIBAL in THF, furnishing the diol functionalized lignin derivative 1 as single diastereomer. The enantiomeric fractions of 1 were obtained by preparative enantioselective HPLC. The absolute stereochemistry was assigned by electronic circular dichroism (ECD) and nuclear magnetic resonance (NMR) spectroscopy. An all-trans relative configuration was determined by NMR on the bases of ¹H coupling constants and nuclear Overhauser effect (n.O.e.) experiments. The absolute configuration at C1 was assigned on the basis of the ECD sign at 296 nm by comparison to the ECD spectra of structural analogues with defined stereochemistry. The assignment of the absolute configuration was confirmed by applying the exciton chirality method to the well-defined ECD couplets at 285 and 200 nm allied to the two electronic transitions L(b) and B(b) of the aromatic moieties, respectively. Rac-1 and its enantiomeric isomers were evaluated against important bacteria responsible for dental caries. The best results obtained for the (1R,2S,3S) isomer were against Streptococcus mutans (250 μM), Streptococcus salivarius (250 μM), Streptococcus sobrinus (280 μM) and Streptococcus mitis (280 μM). The (1S,2R,3R) isomer was active only against Streptococcus sanguinis (280 μM). The enantiomeric mixture was less active than the (1R,2S,3S) isomer.

  7. Bacterial Sugar 3,4-Ketoisomerases: Structural Insight into Product Stereochemistry.

    PubMed

    Thoden, James B; Vinogradov, Evgeny; Gilbert, Michel; Salinger, Ari J; Holden, Hazel M

    2015-07-28

    3-Acetamido-3,6-dideoxy-d-galactose (Fuc3NAc) and 3-acetamido-3,6-dideoxy-d-glucose (Qui3NAc) are unusual sugars found on the lipopolysaccharides of Gram-negative bacteria and on the S-layers of Gram-positive bacteria. The 3,4-ketoisomerases, referred to as FdtA and QdtA, catalyze the third steps in the respective biosynthetic pathways for these sugars. Whereas both enzymes utilize the same substrate, the stereochemistries of their products are different. Specifically, the hydroxyl groups at the hexose C-4' positions assume the "galactose" and "glucose" configurations in the FdtA and QdtA products, respectively. In 2007 we reported the structure of the apoform of FdtA from Aneurinibacillus thermoaerophilus, which was followed in 2014 by the X-ray analysis of QdtA from Thermoanaerobacterium thermosaccharolyticum as a binary complex. Both of these enzymes belong to the cupin superfamily. Here we report a combined structural and enzymological study to explore the manner in which these enzymes control the stereochemistry of their products. Various site-directed mutant proteins of each enzyme were constructed, and their dTDP-sugar products were analyzed by NMR spectroscopy. In addition, the kinetic parameters for these protein variants were measured, and the structure of one, namely, the QdtA Y17R/R97H double mutant form, was determined to 2.3-Å resolution. Finally, in an attempt to obtain a model of FdtA with a bound dTDP-linked sugar, the 3,4-ketoisomerase domain of a bifunctional enzyme from Shewanella denitrificans was cloned, purified, and crystallized in the presence of a dTDP-linked sugar analogue. Taken together, the results from this investigation demonstrate that it is possible to convert a "galacto" enzyme into a "gluco" enzyme and vice versa.

  8. Increasing combat realism: the effectiveness of stun belt use on soldiers for the enhancement of live training and testing exercises

    NASA Astrophysics Data System (ADS)

    Schricker, Bradley C.; Antalek, Christopher

    2006-05-01

    The ability to make correct decisions while operating in a combat zone enables American and Coalition warfighters to better respond to any threats they may encounter due to the minimization of negative training the warfighter encountered during their live, virtual, and constructive (LVC) training exercises. By increasing the physical effects encountered by one's senses during combat scenarios, combat realism is able to be increased, which is a key component in the reduction in negative training. The use of LVC simulations for training and testing augmentation purposes depends on a number of factors, not the least of which is the accurate representation of the training environment. This is particularly true in the realm of tactical engagement training through the use of Tactical Engagement Simulation Systems (TESS). The training environment is perceived through human senses, most notably sight and hearing. As with other haptic devices, the sense of touch is gaining traction as a viable medium through which to express the effects of combat battle damage from the synthetic training environment to participants within a simulated training exercise. New developments in this field are promoting the safe use of an electronic stun device to indicate to a trainee that they have been hit by a projectile, from either direct or indirect fire, through the course of simulated combat. A growing number of examples suggest that this added output medium can greatly enhance the realism of a training exercise and, thus, improve the training value. This paper serves as a literature survey of this concept, beginning with an explanation of TESS. It will then focus on how the electronic stun effect may be employed within a TESS and then detail some of the noted pros and cons of such an approach. The paper will conclude with a description of potential directions and work.

  9. Metacognition and depressive realism: evidence for the level-of-depression account.

    PubMed

    Soderstrom, Nicholas C; Davalos, Deana B; Vázquez, Susana M

    2011-09-01

    Introduction. The present study examined the relationship between metacognition (i.e., "thinking about thinking") and depression. More specifically, the depressive realism hypothesis (Alloy & Abramson, 1979), which posits that depressed people have a more accurate view of reality than nondepressed people, was tested. Methods. Nondepressed, mildly depressed, and moderately depressed individuals predicted their memory performance by making judgements of learning after each studied item. These predictions were then compared with actual performance on a free recall task to assess calibration, an index of metacognitive accuracy. Results and conclusions. Consistent with the depressive realism hypothesis, mild depression was associated with better calibration than nondepression. However, this "sadder but wiser" phenomenon appears to only exist to point, as moderate depression and nondepression showed no calibration differences. Thus, the level-of-depression account of depressive realism is supported.

  10. Did Ptolemy make novel predictions? Launching Ptolemaic astronomy into the scientific realism debate.

    PubMed

    Carman, Christián; Díez, José

    2015-08-01

    The goal of this paper, both historical and philosophical, is to launch a new case into the scientific realism debate: geocentric astronomy. Scientific realism about unobservables claims that the non-observational content of our successful/justified empirical theories is true, or approximately true. The argument that is currently considered the best in favor of scientific realism is the No Miracles Argument: the predictive success of a theory that makes (novel) observational predictions while making use of non-observational content would be inexplicable unless such non-observational content approximately corresponds to the world "out there". Laudan's pessimistic meta-induction challenged this argument, and realists reacted by moving to a "selective" version of realism: the approximately true part of the theory is not its full non-observational content but only the part of it that is responsible for the novel, successful observational predictions. Selective scientific realism has been tested against some of the theories in Laudan's list, but the first member of this list, geocentric astronomy, has been traditionally ignored. Our goal here is to defend that Ptolemy's Geocentrism deserves attention and poses a prima facie strong case against selective realism, since it made several successful, novel predictions based on theoretical hypotheses that do not seem to be retained, not even approximately, by posterior theories. Here, though, we confine our work just to the detailed reconstruction of what we take to be the main novel, successful Ptolemaic predictions, leaving the full analysis and assessment of their significance for the realist thesis to future works.

  11. A DSC investigation on the influence of gemini surfactant stereochemistry on the organization of lipoplexes and on their interaction with model membranes.

    PubMed

    Aleandri, S; Bonicelli, M G; Giansanti, L; Giuliani, C; Ierino, M; Mancini, G; Martino, A; Scipioni, A

    2012-12-01

    Previous investigations showed that the extent of DNA condensation and the efficiency in the transfection of liposomes formulated with 1,2-dimyristoyl-sn-glycero-phosphocholine and cationic stereomeric gemini surfactants depend heavily on the stereochemistry of the gemini. The influence of the stereochemistry on the interaction of lipoplexes with zwitterionic and anionic cell membrane models was investigated by differential scanning calorimetry to rationalize their different biological behavior. Further, the thermotropic behavior of the corresponding liposomes and of the spontaneous self-assemblies of gemini surfactants in the presence and in the absence of DNA was evaluated to correlate the physicochemical properties of lipoplexes and the stereochemistry of the cationic component. The obtained results show that the stereochemistry of the gemini surfactant controls lipoplexes organization and their mode and kinetic of interaction with different cell membrane models.

  12. Objective realism and freedom of choice in relativistic quantum field theory

    NASA Astrophysics Data System (ADS)

    Bednorz, Adam

    2016-10-01

    Traditional Bell's argument shows that freedom of choice is inconsistent with quantum realism if lack of signaling and sufficiently fast choices and readouts are assumed. While no-signaling alone is a consequence of special relativity, this is not the case of spacetime location of choice and readout. Here we attempt to incorporate freedom of choice into quantum objective realism relying solely on relativistic quantum field theory. We conclude that this is impossible without breaking relativistic invariance and put forward the possibility of signaling faster than light, which cannot be excluded if an ultimate theory violates relativity.

  13. Cohaerins G-K, azaphilone pigments from Annulohypoxylon cohaerens and absolute stereochemistry of cohaerins C-K.

    PubMed

    Surup, Frank; Mohr, Kathrin I; Jansen, Rolf; Stadler, Marc

    2013-11-01

    Four azaphilones, for which the trivial names cohaerins G, H, I and K are proposed, were isolated from the methanolic stromatal extract of Annulohypoxylon cohaerens together with the known metabolites cohaerins C-F and 4,5,4',5'-tetrahydroxy-1,1'-binaphthyl (BNT). Their planar structures were determined by NMR spectroscopy and by mass spectrometry. While their core structure is identical with cohaerin C and F, respectively, subgroups 2-hydroxy-6-methylphenyl and (1R,2R,4S)-4-hydroxy-2-methyl-6-oxocyclohexyl account for the structural diversity as substituents at C-3 of the azaphilone core. The absolute stereochemistry was assigned by NOE NMR experiments, CD spectroscopy and derivatisation with Mosher's acid; in addition, the stereochemistry of cohaerins C-F was revised. The metabolites showed cytotoxic effects besides a weak antimicrobial activity.

  14. A new enzyme involved in the control of the stereochemistry in the decalin formation during equisetin biosynthesis.

    PubMed

    Kato, Naoki; Nogawa, Toshihiko; Hirota, Hiroshi; Jang, Jae-Hyuk; Takahashi, Shunji; Ahn, Jong Seog; Osada, Hiroyuki

    2015-05-01

    Tetramic acid containing a decalin ring such as equisetin and phomasetin is one of the characteristic scaffolds found in fungal bioactive secondary metabolites. Polyketide (PKS)-nonribosomal peptide synthetase (NRPS) hybrid enzyme is responsible for the synthesis of the polyketide scaffold conjugated with an amino acid. PKS-NRPS hybrid complex programs to create structural diversity in the polyketide backbone have begun to be investigated, yet mechanism of control of the stereochemistry in a decalin formation via a Diels-Alder cycloaddition remains uncertain. Here, we demonstrate that fsa2, which showed no homology to genes encoding proteins of known function, in the fsa cluster responsible for equisetin and fusarisetin A biosynthesis in Fusarium sp. FN080326, is involved in the control of stereochemistry in decalin formation via a Diels-Alder reaction in the equisetin biosynthetic pathway.

  15. Asymmetric synthesis and absolute stereochemistry of a labdane-type diterpenoid isolated from the rhizomes of Isodan yuennanensis.

    PubMed

    Deng, Heping; Cao, Wei; Zhang, Zhijiang; Liu, Bo

    2016-07-14

    The first synthesis of a labdane-type diterpenoid isolated from Isodon yuennanensis was achieved in fourteen steps from commercially available starting material, (+)-sclareolide. The synthesis features the Barton nitrite ester reaction to introduce an oxime at the angular methyl group and the Jones oxidation to construct the lactone segment. By comparison of the optical rotation of our synthetic sample and the natural sample, the absolute stereochemistry of the natural diterpenoid has been determined.

  16. Fighting with Reality: Considering Mark Johnson's Pragmatic Realism through Bruce Lee's Jeet Kune Do Method

    ERIC Educational Resources Information Center

    Miller, Alexander David

    2015-01-01

    This dissertation considers the supportive and complementary relation between Mark Johnson's embodied realism and Bruce Lee's Jeet Kune Do as a philosophical practice. In exploring this relationship, the emphasis on one's embodiment condition and its relationship with metaphor and self-expression are the primary focus. First, this work involves…

  17. Representational Drawing and the Transition from Intellectual to Visual Realism in Children with Autism

    ERIC Educational Resources Information Center

    Ford, Ruth M.; Rees, Elen Lord

    2008-01-01

    The present study compared the representational drawings of children with autism, children with Down syndrome and typically developing children. Participants were asked to draw a series of objects and their depictions were scored for the incidence of intellectual realism. The tasks sought evidence of conceptual as opposed to episodic influences on…

  18. Standpoint Theory, Realism and the Search for Objectivity in the Sociology of Education

    ERIC Educational Resources Information Center

    Edwards, Gail

    2014-01-01

    This paper evaluates the contribution of "social realism" in resolving questions of knowledge and curriculum in the sociology of education. Social realists argue that, in the interests of educational equality, all pupils should have access to "powerful" knowledge produced by specialist intellectual communities. Social realism…

  19. Emotions Bias Perceptions of Realism in Audiovisual Media: Why We May Take Fiction for Real

    ERIC Educational Resources Information Center

    Konijn, Elly A.; Walma van der Molen, Juliette H.; van Nes, Sander

    2009-01-01

    This study investigated whether emotions induced in TV-viewers (either as an emotional state or co-occurring with emotional involvement) would increase viewers' perception of realism in a fake documentary and affect the information value that viewers would attribute to its content. To that end, two experiments were conducted that manipulated (a)…

  20. The Cultural Work of Magical Realism in Three Young Adult Novels

    ERIC Educational Resources Information Center

    Latham, Don

    2007-01-01

    Magical realism as a literary mode is often subversive and transgressive, questioning the values and assumptions of the dominant society that it depicts. Young adult literature, by contrast, is typically thought to serve a socializing function, helping to integrate young readers into adult society. What then is the cultural work of magical realism…

  1. Depressive Realism and Attributional Style: Implications for Individuals at Risk for Depression

    ERIC Educational Resources Information Center

    Moore, Michael T.; Fresco, David M.

    2007-01-01

    Prior research has found that depressed individuals are more realistic in their interpretations of certain events than nondepressed individuals. However, the implications of this finding for the etiology of depressive disorders have never been clarified. The current investigation sought to remedy this situation by exploring realism in the context…

  2. Explanation and Quantification in Educational Research: The Arguments of Critical and Scientific Realism

    ERIC Educational Resources Information Center

    Nash, Roy

    2005-01-01

    The influence of Bhaskar's critical realism has become increasingly evident in the debate on the nature of educational research. This philosophy, dedicated to the overthrow of positivist doctrines, in particular those of empiricism, nominalism, and causation as constant conjunction, is the foundation of contemporary proposals for new perspectives…

  3. Realism, Authenticity, and Learning in Healthcare Simulations: Rules of Relevance and Irrelevance as Interactive Achievements

    ERIC Educational Resources Information Center

    Rystedt, Hans; Sjoblom, Bjorn

    2012-01-01

    Because simulators offer the possibility of functioning as authentic representations of real-world tasks, these tools are regarded as efficient for developing expertise. The users' experience of realism is recognised as crucial, and is often regarded as an effect of the similarity between reality and the simulator itself. In this study, it is…

  4. Labs and slabs: television crime drama and the quest for forensic realism.

    PubMed

    Jermyn, Deborah

    2013-03-01

    This essay examines how crime dramas produced during, and since, the 1990s became marked by the quest for 'forensic realism'. In particular, the essay traces a landmark shift in the development of forensic realism in the form of the ground-breaking British police drama Prime Suspect in 1991. It is argued that this television series not only represents a turning point in television history, but that it also constitutes a key text in the broader cultural turn towards forensic fascination. Prime Suspect vividly revealed and displayed corpses, crime scenes and post-mortem photos in an unprecedented fashion for television. This essay shows how in the process it established new standards and expectations regarding the aesthetics and thematic content of the perceived 'realism' of the crime genre. Through an analysis of the reception and impact of Prime Suspect the essay also demonstrates how crime drama's increasing fascination with forensic realism has driven debate over just what kinds of stories and images constitute acceptable or appropriate subject matter for popular entertainment, and for the medium of television itself.

  5. Sex differences in visual realism in drawings of animate and inanimate objects.

    PubMed

    Lange-Küttner, Chris

    2011-10-01

    Sex differences in a visually realistic drawing style were examined using the model of a curvy cup as an inanimate object, and the Draw-A-Person test (DAP) as a task involving animate objects, with 7- to 12-year-old children (N = 60; 30 boys). Accurately drawing the internal detail of the cup--indicating interest in a depth feature--was not dependent on age in boys, but only in girls, as 7-year-old boys were already engaging with this cup feature. However, the age effect of the correct omission of an occluded handle--indicating a transition from realism in terms of function (intellectual realism) to one of appearance (visual realism)--was the same for both sexes. The correct omission of the occluded handle was correlated with bilingualism and drawing the internal cup detail in girls, but with drawing the silhouette contour of the cup in boys. Because a figure's silhouette enables object identification from a distance, while perception of detail and language occurs in nearer space, it was concluded that boys and girls may differ in the way they conceptualize depth in pictorial space, rather than in visual realism as such.

  6. A Proposal for Testing Local Realism Without Using Assumptions Related to Hidden Variable States

    NASA Technical Reports Server (NTRS)

    Ryff, Luiz Carlos

    1996-01-01

    A feasible experiment is discussed which allows us to prove a Bell's theorem for two particles without using an inequality. The experiment could be used to test local realism against quantum mechanics without the introduction of additional assumptions related to hidden variables states. Only assumptions based on direct experimental observation are needed.

  7. The accuracy of meta-metacognitive judgments: regulating the realism of confidence.

    PubMed

    Buratti, Sandra; Allwood, Carl Martin

    2012-08-01

    Can people improve the realism of their confidence judgments about the correctness of their episodic memory reports by deselecting the least realistic judgments? An assumption of Koriat and Goldsmith's (Psychol Rev 103:490-517, 1996) model is that confidence judgments regulate the reporting of memory reports. We tested whether this assumption generalizes to the regulation of the realism (accuracy) of confidence judgments. In two experiments, 270 adults in separate conditions answered 50 recognition and recall questions about the contents of a just-seen video. After each answer, they made confidence judgments about the answer's correctness. In Experiment 1, the participants in the recognition conditions significantly increased their absolute bias when they excluded 15 questions. In Experiment 2, the participants in the recall condition significantly improved their calibration. The results indicate that recall, more than recognition, offers valid cues for participants to increase the realism of their report. However, the effects were small with only weak support for the conclusion that people have some ability to regulate the realism in their confidence judgments.

  8. Televised Entertainment-Education to Prevent Adolescent Alcohol Use: Perceived Realism, Enjoyment, and Impact

    ERIC Educational Resources Information Center

    van Leeuwen, Lonneke; Renes, Reint Jan; Leeuwis, Cees

    2013-01-01

    Alcohol use among adolescents is a concern in the Netherlands because of its high prevalence and risks. To discourage adolescents from drinking alcohol, a televised entertainment-education (E-E) intervention was developed. This study investigated responses of adolescents on perceived realism and enjoyment of the E-E intervention, as well as its…

  9. THE INTERSECTION OF INDEPENDENT LIES: INCREASING REALISM IN ECOLOGICAL RISK ASSESSMENT

    EPA Science Inventory

    In 1966, Levins presented a philosophical discussion on making inference about populations using clusters of models. In this article we provide an overview of model inference in ecological risk assessment, discuss the benefits and trade-offs of increasing model realism, show the...

  10. A mismatch in the human realism of face and voice produces an uncanny valley.

    PubMed

    Mitchell, Wade J; Szerszen, Kevin A; Lu, Amy Shirong; Schermerhorn, Paul W; Scheutz, Matthias; Macdorman, Karl F

    2011-01-01

    The uncanny valley has become synonymous with the uneasy feeling of viewing an animated character or robot that looks imperfectly human. Although previous uncanny valley experiments have focused on relations among a character's visual elements, the current experiment examines whether a mismatch in the human realism of a character's face and voice causes it to be evaluated as eerie. The results support this hypothesis.

  11. ELECTRON DETACHMENT DISSOCIATION OF SYNTHETIC HEPARAN SULFATE GLYCOSAMINOGLYCAN TETRASACCHARIDES VARYING IN DEGREE OF SULFATION AND HEXURONIC ACID STEREOCHEMISTRY.

    PubMed

    Leach, Franklin E; Arungundram, Sailaja; Al-Mafraji, Kanar; Venot, Andre; Boons, Geert-Jan; Amster, I Jonathan

    2012-12-15

    Glycosaminoglycan (GAG) carbohydrates provide a challenging analytical target for structural determination due to their polydisperse nature, non-template biosynthesis, and labile sulfate modifications. The resultant structures, although heterogeneous, contain domains which indicate a sulfation pattern or code that correlates to specific function. Mass spectrometry, in particular electron detachment dissociation Fourier transform ion cyclotron resonance (EDD FT-ICR MS), provides a highly sensitive platform for GAG structural analysis by providing cross-ring cleavages for sulfation location and product ions specific to hexuronic acid stereochemistry. To investigate the effect of sulfation pattern and variations in stereochemistry on EDD spectra, a series of synthetic heparan sulfate (HS) tetrasaccharides are examined. Whereas previous studies have focused on lowly sulfated compounds (0.5-1 sulfate groups per disaccharide), the current work extends the application of EDD to more highly sulfated tetrasaccharides (1-2 sulfate groups per disaccharide) and presents the first EDD of a tetrasaccharide containing a sulfated hexuronic acid. For these more highly sulfated HS oligomers, alternative strategies are shown to be effective for extracting full structural details. These strategies inlcude sodium cation replacement of protons, for determining the sites of sulfation, and desulfation of the oligosaccharides for the generation of product ions for assigning uronic acid stereochemistry.

  12. A bacterial tyrosine aminomutase proceeds through retention or inversion of stereochemistry to catalyze its isomerization reaction.

    PubMed

    Wanninayake, Udayanga; Walker, Kevin D

    2013-07-31

    β-Amino acids are biologically active compounds of interest in medicinal chemistry. A class I lyase-like family of aminomutases isomerizes (S)-α-arylalanines to the corresponding β-amino acids by exchange of the NH2/H pair. This family uses a 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO) group within the active site to initiate the reaction. The absolute stereochemistry of the product is known for an MIO-dependent tyrosine aminomutase from Chondromyces crocatus (CcTAM) that isomerizes (S)-α-tyrosine to (R)-β-tyrosine. To evaluate the cryptic stereochemistry of the CcTAM mechanism, (2S,3S)-[2,3-(2)H2]- and (2S,3R)-[3-(2)H]-α-tyrosine were stereoselectively synthesized from unlabeled (or [(2)H]-labeled) (4'-hydroxyphenyl)acrylic acids by reduction with D2 (or H2) gas and a chiral Rh-Prophos catalyst. GC/EIMS analysis of the [(2)H]-β-tyrosine biosynthesized by CcTAM revealed that the α-amino group was transferred to Cβ of the phenylpropanoid skeleton with retention of configuration. These labeled substrates also showed that the pro-(3S) proton exchanges with protons from the bulk media during its migration to Cα during catalysis. (1)H- and (2)H NMR analyses of the [(2)H]-β-tyrosine derived from (2S)-[3,3-(2)H2]-α-tyrosine by CcTAM catalysis showed that the migratory proton attached to Cα of the product also with retention of configuration. CcTAM is stereoselective for (R)-β-tyrosine (85%) yet also forms the (S)-β-tyrosine enantiomer (15%) through inversion of configuration at both migration termini, as described herein. The proportion of the (S)-β-isomer made by CcTAM during steady state interestingly increased with solvent pH, and this effect on the proposed reaction mechanism is also discussed.

  13. Assignment of the stereochemistry and anomeric configuration of structurally informative product ions derived from disaccharides: infrared photodissociation of glycosyl-glycolaldehydes in the negative ion mode.

    PubMed

    Bendiak, Brad; Fang, Tammy T

    2010-11-02

    Using mass spectrometry in the negative ion mode, m/z 221 ions are frequently observed as product ion substructures derived from reducing disaccharides having 2, 4, or 6 linkages. The ions have been shown to be glycosyl-glycolaldehydes. All 16 stereochemical variants of their pyranosides were prepared and evaluated by infrared photodissociation, in addition to HexNAc-glycolaldehyde variants (m/z 262) of 2-acetamido-2-deoxy-d-glucose and 2-acetamido-2-deoxy-d-galactose. The stereochemistry and anomeric configuration of these ions were differentiated in the gas phase using a Fourier transform ion cyclotron resonance spectrometer with infrared multiphoton dissociation at 10.6 μm. Results were compared to those obtained by collision-induced dissociation. In some cases, differentiation was far preferable using infrared photodissociation; in others, collision-induced dissociation was preferred. Using an instrument that interfaced a linear trap with a Fourier transform ion cyclotron resonance spectrometer, either dissociation technique could be used to optimally discriminate between isomers. With infrared photodissociation, spectral differences were highly statistically significant, even between pairs of isomers having spectra that appeared to be visually somewhat similar (p<1×10⁻⁹, student's t-test for key discriminatory ions). Comparisons among different instruments suggest that physical standards of the stereochemical variants of these ions will be required for their detailed structural assignments in unknowns, as some variation was observed among instruments, both using infrared photodissociation and collision-induced dissociation.

  14. The Acquisition of Stereochemical Knowledge by Algerian Students Intending to Teach Physical Sciences

    ERIC Educational Resources Information Center

    Boukhechem, Mohamed-Salah; Dumon, Alain; Zouikri, Mohamed

    2011-01-01

    In this work we evaluated the level of difficulty found in learning stereochemistry concepts, by students intending to teach physical sciences at the Ecole Normale Superieure (ENS) Kouba (Algeria). A paper and pencil questionnaire was administered to 170 students to evaluate: their familiarity with Newman representations; their ability of linking…

  15. Absolute stereochemistry of fungal beauveriolide III and ACAT inhibitory activity of four stereoisomers.

    PubMed

    Ohshiro, Taichi; Namatame, Ichiji; Nagai, Kenichiro; Sekiguchi, Takafumi; Doi, Takayuki; Takahashi, Takashi; Akasaka, Kazuaki; Rudel, Lawrence L; Tomoda, Hiroshi; Omura, Satoshi

    2006-09-29

    Fungal beauveriolide III (BeauIII, 1b), a cyclodepsipeptide inhibiting acyl-CoA:cholesterol acyltransferase (ACAT) and showing antiatherogenic activity in mouse models, consists of L-Phe, L-Ala, D-allo-Ile, and 3-hydroxy-4-methyloctanoic acid (HMA) moieties, but the stereochemistry of the HMA part has not until now been fully defined. To determine it, four HMA stereoisomers were synthesized and labeled with (S)-(+)-2-(anthracene-2,3-dicarboximido)-1-propyl trifluoromethane sulfonate (AP-OTf), a chiral fluorescent reagent. The derivatives were separated by HPLC and compared with the natural HMA derivative, which was thereby identified as (3S,4S)HMA in BeauIII. Furthermore, the four beauveriolide III isomers ((3S,4S)BeauIII (23a), (3R,4R)BeauIII (23b), (3R,4S)BeauIII (23c), and (3S,4R)BeauIII (23d)) were synthesized, and it was shown that all the spectral data for 23a were identical with those for natural 1b. Isomers 23a and 23d showed potent inhibitory activity of lipid droplet accumulation in macrophages, while the other two isomers caused weak inhibition. Thus, the 3S configuration of BeauIII is important for this activity. Furthermore, 23a and 23d showed rather specific inhibition against the ACAT1 isozyme.

  16. Regiochemistry and stereochemistry of the biosynthesis of vitamin B6 from triose units

    SciTech Connect

    Hill, R.E.; Iwanow, A.; Sayer, B.G.; Wysocka, W.; Spenser, I.D.

    1987-06-05

    /sup 13/C and /sup 2/H NMR spectroscopy has been employed to probe the biosynthesis of vitamin B6 in Escherichia coli. The /sup 13/C NMR spectrum of a sample of pyridoxol derived biosynthetically from D-(1,2,3,4,5,6-13C6)glucose shows that the bonds, C(2)-C(3) and C(4)-C(5), of the pyridine nucleus are the only two carbon-carbon bonds of pyridoxol which are generated de novo in the course of its biosynthesis from glucose. It follows that the pyridoxol skeleton is generated from two intact triose units and a triose-derived two-carbon unit, all of which are supplied by glucose. From the /sup 2/H NMR spectra of samples of pyridoxol derived from (R)-(1,1-/sup 2/H/sub 2/)glycerol and (S)-(1,1-/sup 2/H/sub 2/)glycerol, respectively, it can be deduced that the rehydroxymethyl group of glycerol enters C-2', C-4', and C-5' of the pyridoxol skeleton. It follows that each of the three fragments is derived from glycerol in stereo-specific fashion. These results answer questions concerning the regiochemistry and the stereochemistry of pyridoxol biosynthesis.

  17. Controlling the stereochemistry and regularity of butanethiol self-assembled monolayers on au(111).

    PubMed

    Yan, Jiawei; Ouyang, Runhai; Jensen, Palle S; Ascic, Erhad; Tanner, David; Mao, Bingwei; Zhang, Jingdong; Tang, Chunguang; Hush, Noel S; Ulstrup, Jens; Reimers, Jeffrey R

    2014-12-10

    The rich stereochemistry of the self-assembled monolayers (SAMs) of four butanethiols on Au(111) is described, the SAMs containing up to 12 individual C, S, or Au chiral centers per surface unit cell. This is facilitated by synthesis of enantiomerically pure 2-butanethiol (the smallest unsubstituted chiral alkanethiol), followed by in situ scanning tunneling microscopy (STM) imaging combined with density functional theory molecular dynamics STM image simulations. Even though butanethiol SAMs manifest strong headgroup interactions, steric interactions are shown to dominate SAM structure and chirality. Indeed, steric interactions are shown to dictate the nature of the headgroup itself, whether it takes on the adatom-bound motif RS(•)Au(0)S(•)R or involves direct binding of RS(•) to face-centered-cubic or hexagonal-close-packed sites. Binding as RS(•) produces large, organizationally chiral domains even when R is achiral, while adatom binding leads to rectangular plane groups that suppress long-range expression of chirality. Binding as RS(•) also inhibits the pitting intrinsically associated with adatom binding, desirably producing more regularly structured SAMs.

  18. Sequence variation determining stereochemistry of a Δ11 desaturase active in moth sex pheromone biosynthesis.

    PubMed

    Ding, Bao-Jian; Carraher, Colm; Löfstedt, Christer

    2016-07-01

    A Δ11 desaturase from the oblique banded leaf roller moth Choristoneura rosaceana takes the saturated myristic acid and produces a mixture of (E)-11-tetradecenoate and (Z)-11-tetradecenoate with an excess of the Z isomer (35:65). A desaturase from the spotted fireworm moth Choristoneura parallela also operates on myristic acid substrate but produces almost pure (E)-11-tetradecenoate. The two desaturases share 92% amino acid identity and 97% amino acid similarity. There are 24 amino acids differing between these two desaturases. We constructed mutations at all of these positions to pinpoint the sites that determine the product stereochemistry. We demonstrated with a yeast functional assay that one amino acid at the cytosolic carboxyl terminus of the protein (258E) is critical for the Z activity of the C. rosaceana desaturase. Mutating the glutamic acid (E) into aspartic acid (D) transforms the C. rosaceana enzyme into a desaturase with C. parallela-like activity, whereas the reciprocal mutation of the C. parallela desaturase transformed it into an enzyme producing an intermediate 64:36 E/Z product ratio. We discuss the causal link between this amino acid change and the stereochemical properties of the desaturase and the role of desaturase mutations in pheromone evolution.

  19. Methods for the comprehensive structural elucidation of constitution and stereochemistry of lipopeptides.

    PubMed

    Gerhardt, Heike; Sievers-Engler, Adrian; Jahanshah, Ghazaleh; Pataj, Zoltán; Ianni, Federica; Gross, Harald; Lindner, Wolfgang; Lämmerhofer, Michael

    2016-01-08

    A panel of methods of general suitability for complete structural elucidation of the stereochemistry of cyclopeptides, depsipeptides and lipopeptides is presented and described in detail. The suitability of the proposed methods was exemplified on the lipopeptide poaeamide from Pseudomonas poae. Amino acid configurations have been assigned by direct LC enantiomer separation with Chiralpak ZWIX(+) and were confirmed by GC enantiomer separation on Chirasil L-Val. 3-Hydroxydecanoic acid absolute configuration was analyzed on Chiralpak ZWIX(+) and confirmed by injection on ZWIX(-) which showed opposite elution order. Plenty of d-amino acids have been found in this lipopeptide. It contained in total 5 Leu residues of which one had d-configuration. The position of the d-Leu in the peptide sequence was determined by pepsin and chemical digestions in combination with isolation of diagnostic peptide-fragments and subsequent identification of absolute configurations of the Leu residues. This allowed pinpointing the position of the d-amino acid. The complementarity of the peptide retention profiles on Chiralpak ZWIX column as compared to both RPLC and HILIC suggests its great utility as an alternative peptide separation tool.

  20. Absolute Stereochemistry of the β-Hydroxy Acid Unit in Hantupeptins and Trungapeptins.

    PubMed

    Gupta, Deepak Kumar; Ding, Gary Chi Ying; Teo, Yong Chua; Tan, Lik Tong

    2016-01-01

    The β-hydroxy/amino acid unit is a common structural feature of many bioactive marine cyanobacterial depsipeptides. In this study, the absolute stereochemistry of the β-hydroxy acid moieties in hantupeptins and trungapeptins were determined through their synthesis and HPLC analysis of the Mosher ester derivatives. Synthesis of two3-hydroxy-2-methyloctanoic acid (Hmoa) stereoisomers, (2S,3R)-Hmoa and (2S,3S)-Hmoa, were achieved using diastereoselective asymmetric method and the retention times of all four Hmoa isomers were established indirectly by RPLC-MS analysis of their Mosher ester derivative standards. Based on the retention times of the standards, the absolute configuration of the Hmoa unit in hantupeptin C (3) and trungapeptin C (6) was assigned as (2R,3S)- and (2S,3R)-Hmoa, respectively. The use of the Mosher's reagents, coupled with HPLC analysis, provided a viable alternative to the absolute stereochemical determination of β-hydroxy acid units in depsipeptides.

  1. Correlation between the Stereochemistry and Bioactivity in Octahedral Rhodium Prolinato Complexes.

    PubMed

    Rajaratnam, Rajathees; Martin, Elisabeth K; Dörr, Markus; Harms, Klaus; Casini, Angela; Meggers, Eric

    2015-08-17

    Controlling the relative and absolute configuration of octahedral metal complexes constitutes a key challenge that needs to be overcome in order to fully exploit the structural properties of octahedral metal complexes for applications in the fields of catalysis, materials sciences, and life sciences. Herein, we describe the application of a proline-based chiral tridentate ligand to decisively control the coordination mode of an octahedral rhodium(III) complex. We demonstrate the mirror-like relationship of synthesized enantiomers and differences between diastereomers. Further, we demonstrate, using the established pyridocarbazole pharmacophore ligand as part of the organometallic complexes, the importance of the relative and absolute stereochemistry at the metal toward chiral environments like protein kinases. Protein kinase profiling and inhibition data confirm that the proline-based enantiopure rhodium(III) complexes, despite having all of the same constitution, differ strongly in their selectivity properties despite their unmistakably mutual origin. Moreover, two exemplary compounds have been shown to induce different toxic effects in an ex vivo rat liver model.

  2. Study of the Stereochemistry and Oxidation Mechanism of Plant Polyphenols, Assisted by Computational Chemistry.

    PubMed

    Matsuo, Yosuke

    2017-01-01

     In recent years, plant polyphenols have attracted great attention due to their wide range of biological activities. Certain kinds of polyphenols have complex structures; therefore, it is difficult to elucidate their total structure, including stereochemistry. In this study, we reinvestigated the stereostructures of two major C-glycosidic ellagitannins contained in Quercus plants, vescalagin and castalagin, and revised their stereostructures based on theoretical calculations of spectroscopic data. We also determined the structures of quercusnins A and B, isolated from the sapwood of Quercus crispula, based on theoretical calculations of NMR data. The oxidation mechanism of polyphenols has not been entirely elucidated. Therefore, we have also studied the oxidation mechanism of tea catechins during black tea production. Our investigation of the oxidation mechanism of black tea pigment theaflavins revealed that the difference in the position of the galloyl ester affords different oxidation products of theaflavins. In addition, oxidation products of pyrogallol-type catechins could be classified into three types-dehydrotheasinensins, theacitrins, and proepitheaflagallins; their detailed production and degradation mechanisms were also examined.

  3. Temperature-dependent annuloselectivity and stereochemistry in the reactions of methanesulfonyl sulfene with imines.

    PubMed

    Wu, Qiuyue; Yang, Zhanhui; Xu, Jiaxi

    2016-07-26

    The annuloselectivity in the reactions of methanesulfonyl sulfene and imines varies with temperature. At a relatively higher temperature of 20 °C, the [2(s) + 2(i)] annulation of different N-alkyl imines occurs exclusively, giving four-membered trans-β-sultams in up to 69% yields. At a lower temperature of -78 °C, the [2(s) + 2(i) + 2(i)] annulation of N-methyl imines takes place specifically, delivering six-membered 1,2,4-thiadiazine 1,1-dioxides, 4-aza-δ-sultams, in up to 80% yields, with diverse configurations at the C3, C5, and C6 stereocenters. The trans-stereochemistry involved in the [2(s) + 2(i)] annulations is attributed to the conrotatory ring closure of the thermodynamically stable 2,3-thiazabutadiene-type zwitterionic intermediates, while the diverse stereochemical outcomes in the [2(s) + 2(i) + 2(i)] annulations are caused by the iminium isomerization in the stepwise nucleophilic [4 + 2] annulation between the same zwitterionic intermediates and a second molecule of N-methyl imines.

  4. Isolation of brassicasterol, its synthetic prodrug-crystal structure, stereochemistry and theoretical studies

    NASA Astrophysics Data System (ADS)

    Sethi, Arun; Prakash, Rohit; Srivastava, Sangeeta; Amandeep; Bishnoi, Abha; Singh, Ranvijay Pratap

    2014-07-01

    In the present study brassicasterol (1), was isolated from the chloroform extract of the flowers of Allamanda violacea and identified with the help of different spectroscopic techniques like 1H, 13C, 2D NMR (1H-1H COSY), IR, UV and mass spectrometry. A novel prodrug was synthesized by carrying out esterification of brassicasterol (1) with the well known drug naproxen using Steglich esterification to give 3β-(2-(6-methoxynaphthalene-2yl) propionoxy) 24 methyl cholest-5, 22-dien (2). Compounds 2 was subjected to single crystal X-ray diffraction technique and crystallized out in monoclinic form having P21 space group and stabilized by CH-π interactions. Structure and stereochemistry of compound 2 was established with the help of modern spectroscopic techniques like 1H NMR, IR, UV, mass spectrometry as well as with single crystal X-ray diffraction. Molecular geometry and vibrational frequencies of compounds 1 and 2 were calculated by density functional method (DFT/B3LYP) using 6-31G (d, p) basis set, bond parameters and IR frequencies were correlated with the experimental data. 1H and 13C chemical shifts of compound 1 and 1H chemical shifts of compound 2 were calculated with GIAO method and correlated with experimental data. Hyperconjugative interactions were studied with the help of natural bond order analysis (NBO). Electronic properties of both the compounds such as HOMO-LUMO energies were measured with the help of time dependent DFT method.

  5. Accurate stereochemistry for two related 22,26-epimino­cholestene derivatives

    PubMed Central

    Vega-Baez, José Luis; Sandoval-Ramírez, Jesús; Meza-Reyes, Socorro; Montiel-Smith, Sara; Gómez-Calvario, Victor; Bernès, Sylvain

    2008-01-01

    Regioselective opening of ring E of solasodine under various conditions afforded (25R)-22,26-epimino­cholesta-5,22(N)-di­ene-3β,16β-diyl diacetate (previously known as 3,16-diacetyl pseudosolasodine B), C31H47NO4, or (22S,25R)-16β-hydr­oxy-22,26-epimino­cholesta-5-en-3β-yl acetate (a derivative of the naturally occurring alkaloid oblonginine), C29H47NO3. In both cases, the reactions are carried out with retention of chirality at the C16, C20 and C25 stereogenic centers, which are found to be S, S and R, respectively. Although pseudosolasodine was synthesized 50 years ago, these accurate assignments clarify some controversial points about the actual stereochemistry for these alkaloids. This is of particular importance in the case of oblonginine, since this compound is currently under consideration for the treatment of aphasia arising from apoplexy; the present study defines a diastereoisomerically pure compound for pharmacological studies. PMID:18391392

  6. Cognitive components of naming in children: effects of referential uncertainty and stimulus realism.

    PubMed

    Johnson, C J

    1992-02-01

    The ease of picture naming in children was assessed as a function of two stimulus characteristics: (a) the number of available correct names for a picture (referential uncertainty) and (b) the degree to which a picture realistically represents the depicted object (stimulus realism). Two experiments employing different methods demonstrated that: (a) children named low uncertainty objects (those with a single dominant name, e.g., key, elephant) faster than high uncertainty objects (those with multiple possible correct names, e.g., lamp/light, stove/oven) and (b) this uncertainty effect arose at a stage of naming subsequent to object identification. Possible underlying mechanisms for the uncertainty effect include passive diffusion of activation over multiple object-name pathways or active inhibition among competing candidate names. Stimulus realism (colored photographs vs uncolored line drawings) did not consistently influence naming performance. Implications for understanding children's naming behavior are discussed.

  7. Decoherence-free emergence of macroscopic local realism for entangled photons in a cavity

    SciTech Connect

    Portolan, S.; Rossi, F.; Di Stefano, O.; Savasta, S.; Girlanda, R.

    2006-02-15

    We investigate the influence of environmental noise on polarization entangled light generated by parametric emission in a cavity. By adopting a recent separability criterion, we show that (i) self-stimulation may suppress the detrimental influence of noise on entanglement, but (ii) once it becomes effective, a noise-equipped classical model of parametric emission provides the same results of quantum theory with respect to the separability criterion. More generally we also show that, in the macroscopic limit, it is not possible to observe violations of local realism with measurements of finite order n-particle correlations only. These results provide a prototypical case of the emergence of macroscopic local realism in the presence of strong entanglement even in the absence of decoherence.

  8. Positioning positivism, critical realism and social constructionism in the health sciences: a philosophical orientation.

    PubMed

    Cruickshank, Justin

    2012-03-01

    Positioning positivism, critical realism and social constructionism in the health sciences: a philosophical orientation This article starts by considering the differences within the positivist tradition and then it moves on to compare two of the most prominent schools of postpositivism, namely critical realism and social constructionism. Critical realists hold, with positivism, that knowledge should be positively applied, but reject the positivist method for doing this, arguing that causal explanations have to be based not on empirical regularities but on references to unobservable structures. Social constructionists take a different approach to postpositivism and endorse a relativist rejection of truth and hold that the task of research is to foster a scepticism that undermines any positive truth claim made. It is argued that social constructionism is a contradictory position.

  9. Coronavirus receptor switch explained from the stereochemistry of protein–carbohydrate interactions and a single mutation

    PubMed Central

    Bakkers, Mark J. G.; Zeng, Qinghong; Feitsma, Louris J.; Hulswit, Ruben J. G.; Li, Zeshi; Westerbeke, Aniek; van Kuppeveld, Frank J. M.; Boons, Geert-Jan; Langereis, Martijn A.; de Groot, Raoul J.

    2016-01-01

    Hemagglutinin-esterases (HEs) are bimodular envelope proteins of orthomyxoviruses, toroviruses, and coronaviruses with a carbohydrate-binding “lectin” domain appended to a receptor-destroying sialate-O-acetylesterase (“esterase”). In concert, these domains facilitate dynamic virion attachment to cell-surface sialoglycans. Most HEs (type I) target 9-O-acetylated sialic acids (9-O-Ac-Sias), but one group of coronaviruses switched to using 4-O-Ac-Sias instead (type II). This specificity shift required quasisynchronous adaptations in the Sia-binding sites of both lectin and esterase domains. Previously, a partially disordered crystal structure of a type II HE revealed how the shift in lectin ligand specificity was achieved. How the switch in esterase substrate specificity was realized remained unresolved, however. Here, we present a complete structure of a type II HE with a receptor analog in the catalytic site and identify the mutations underlying the 9-O- to 4-O-Ac-Sia substrate switch. We show that (i) common principles pertaining to the stereochemistry of protein–carbohydrate interactions were at the core of the transition in lectin ligand and esterase substrate specificity; (ii) in consequence, the switch in O-Ac-Sia specificity could be readily accomplished via convergent intramolecular coevolution with only modest architectural changes in lectin and esterase domains; and (iii) a single, inconspicuous Ala-to-Ser substitution in the catalytic site was key to the emergence of the type II HEs. Our findings provide fundamental insights into how proteins “see” sugars and how this affects protein and virus evolution. PMID:27185912

  10. Coronavirus receptor switch explained from the stereochemistry of protein-carbohydrate interactions and a single mutation.

    PubMed

    Bakkers, Mark J G; Zeng, Qinghong; Feitsma, Louris J; Hulswit, Ruben J G; Li, Zeshi; Westerbeke, Aniek; van Kuppeveld, Frank J M; Boons, Geert-Jan; Langereis, Martijn A; Huizinga, Eric G; de Groot, Raoul J

    2016-05-31

    Hemagglutinin-esterases (HEs) are bimodular envelope proteins of orthomyxoviruses, toroviruses, and coronaviruses with a carbohydrate-binding "lectin" domain appended to a receptor-destroying sialate-O-acetylesterase ("esterase"). In concert, these domains facilitate dynamic virion attachment to cell-surface sialoglycans. Most HEs (type I) target 9-O-acetylated sialic acids (9-O-Ac-Sias), but one group of coronaviruses switched to using 4-O-Ac-Sias instead (type II). This specificity shift required quasisynchronous adaptations in the Sia-binding sites of both lectin and esterase domains. Previously, a partially disordered crystal structure of a type II HE revealed how the shift in lectin ligand specificity was achieved. How the switch in esterase substrate specificity was realized remained unresolved, however. Here, we present a complete structure of a type II HE with a receptor analog in the catalytic site and identify the mutations underlying the 9-O- to 4-O-Ac-Sia substrate switch. We show that (i) common principles pertaining to the stereochemistry of protein-carbohydrate interactions were at the core of the transition in lectin ligand and esterase substrate specificity; (ii) in consequence, the switch in O-Ac-Sia specificity could be readily accomplished via convergent intramolecular coevolution with only modest architectural changes in lectin and esterase domains; and (iii) a single, inconspicuous Ala-to-Ser substitution in the catalytic site was key to the emergence of the type II HEs. Our findings provide fundamental insights into how proteins "see" sugars and how this affects protein and virus evolution.

  11. Synthesis, stereochemistry determination, pharmacological studies and quantum chemical analyses of bisthiazolidinone derivative

    NASA Astrophysics Data System (ADS)

    Mushtaque, Md.; Avecilla, Fernando; Hafeez, Zubair Bin; Jahan, Meriyam; Khan, Md. Shahzad; Rizvi, M. Moshahid A.; Khan, Mohd. Shahid; Srivastava, Anurag; Mallik, Anwesha; Verma, Saurabh

    2017-01-01

    A new compound (3) bisthaizolidinone derivative was synthesized by Knoevenagel condensation reaction. The structure of synthesized compound was elucidated by different spectral techniques and X-ray diffraction studies. The stereochemistry of the compound (3) was determined by 1Hsbnd 1H NOESY, 1Hsbnd 1H NMR COSY and single crystal X-ray diffraction studies as (Z, Z)-configuration. The computational quantum chemical studies of compound(3) like, IR, UV, NBO analysis were performed by DFT with Becke-3-Lee-Yang-Parr (B3LYP) exchange-correlation functional in combination with 6-311++G(d,p) basis sets. The DNA-binding of compound (3) exhibited a moderate binding constant (Kb = 1 × 105 Lmol-1) with hypochromic shift. The molecular docking displayed good binding affinity -7.18 kcal/mol. The MTT assay of compound (3) was screened against different cancerous cell lines, HepG2, Siha, Hela and MCF-7. Studies against these cell lines depicted that the screened compound (3) showed potent inhibitory activity against HepG2 cell (IC50 = 7.5 μM) followed by MCF-7 (IC50 = 52.0 μM), Siha (IC50 = 66.98 μM), Hela (IC50 = 74.83 μM) cell lines, and non-toxic effect against non-cancerous HEK-293 cells (IC50 = 287.89 μM) at the concentration range (0-300) μM. Furthermore, cell cycle perturbation was performed on HepG2 & Siha cell lines and observed that cells were arrested in G2/M in HepG2, and G0/G1 in Siha cell lines with respect to untreated control. Hence, compound (3) possesses potent anti-cancerous activity against HepG2 cell line.

  12. Three factors that influence the overall quality of the stereoscopic 3D content: image quality, comfort, and realism

    NASA Astrophysics Data System (ADS)

    Vlad, Raluca; Ladret, Patricia; Guérin, Anne

    2013-01-01

    In today's context, where 3D content is more abundant than ever and its acceptance by the public is probably de_nitive, there are many discussions on controlling and improving the 3D quality. But what does this notion represent precisely? How can it be formalized and standardized? How can it be correctly evaluated? A great number of studies have investigated these matters and many interesting approaches have been proposed. Despite this, no universal 3D quality model has been accepted so far that would allow a uniform across studies assessment of the overall quality of 3D content, as it is perceived by the human observers. In this paper, we are making a step forward in the development of a 3D quality model, by presenting the results of an exploratory study in which we started from the premise that the overall 3D perceived quality is a multidimensional concept that can be explained by the physical characteristics of the 3D content. We investigated the spontaneous impressions of the participants while watching varied 3D content, we analyzed the key notions that appeared in their discourse and identi_ed correlations between their judgments and the characteristics of our database. The test proved to be rich in results. Among its conclusions, we consider of highest importance the fact that we could thus determine three di_erent perceptual attributes ( image quality, comfort and realism ( that could constitute a _rst simplistic model for assessing the perceived 3D quality.

  13. Experimental violation of the local realism for four-qubit Dicke state.

    PubMed

    Zhao, Yuan-Yuan; Wu, Yu-Chun; Xiang, Guo-Yong; Li, Chuan-Feng; Guo, Guang-Can

    2015-11-16

    Dicke state is an widely used type of multi-particle entangled state in quantum information. However, very few works have been done on its nonlocality. Here we prepare a four-photon symmetric Dicke state, whose fidelity is as high as 0.904 ± 0.004, and devise a simple Bell-type inequality to demonstrate that it violates the local realism with 12 standard deviation.

  14. Design, synthesis and in vitro evaluation of a series of α-substituted phenylpropanoic acid PPARγ agonists to further investigate the stereochemistry-activity relationship.

    PubMed

    Ohashi, Masao; Nakagome, Izumi; Kasuga, Jun-Ichi; Nobusada, Hiromi; Matsuno, Kenji; Makishima, Makoto; Hirono, Shuichi; Hashimoto, Yuichi; Miyachi, Hiroyuki

    2012-11-01

    We previously demonstrated that the α-benzylphenylpropanoic acid-type PPARγ-selective agonist 6 exhibited a reversed stereochemistry-activity relationship, that is, the (R)-enantiomer is a more potent PPARγ agonist than the (S)-enantiomer, compared with structurally similar α-ethylphenylpropanoic acid-type PPAR agonists. Here, we designed, synthesized and evaluated the optically active α-cyclohexylmethylphenylpropanoic acid derivatives 7 and α-phenethylphenylpropanoic acid derivatives 8, respectively. Interestingly, α-cyclohexylmethyl derivatives showed reversal of the stereochemistry-activity relationship [i.e., (R) more potent than (S)], like α-benzyl derivatives, whereas α-phenethyl derivatives showed the 'normal' relationship [(S) more potent than (R)]. These results suggested that the presence of a branched carbon atom at the β-position with respect to the carboxyl group is a critical determinant of the reversed stereochemistry-activity relationship.

  15. Multivariate analysis of electron detachment dissociation and infrared multiphoton dissociation mass spectra of heparan sulfate tetrasaccharides differing only in hexuronic acid stereochemistry.

    PubMed

    Oh, Han Bin; Leach, Franklin E; Arungundram, Sailaja; Al-Mafraji, Kanar; Venot, Andre; Boons, Geert-Jan; Amster, I Jonathan

    2011-03-01

    The structural characterization of glycosaminoglycan (GAG) carbohydrates by mass spectrometry has been a long-standing analytical challenge due to the inherent heterogeneity of these biomolecules, specifically polydispersity, variability in sulfation, and hexuronic acid stereochemistry. Recent advances in tandem mass spectrometry methods employing threshold and electron-based ion activation have resulted in the ability to determine the location of the labile sulfate modification as well as assign the stereochemistry of hexuronic acid residues. To facilitate the analysis of complex electron detachment dissociation (EDD) spectra, principal component analysis (PCA) is employed to differentiate the hexuronic acid stereochemistry of four synthetic GAG epimers whose EDD spectra are nearly identical upon visual inspection. For comparison, PCA is also applied to infrared multiphoton dissociation spectra (IRMPD) of the examined epimers. To assess the applicability of multivariate methods in GAG mixture analysis, PCA is utilized to identify the relative content of two epimers in a binary mixture.

  16. Exploring the relationship between object realism and object-based attention effects.

    PubMed

    Roque, Nelson; Boot, Walter R

    2015-09-01

    Visual attention prioritizes processing of locations in space, and evidence also suggests that the benefits of attention can be shaped by the presence of objects (object-based attention). However, the prevalence of object-based attention effects has been called into question recently by evidence from a large-sampled study employing classic attention paradigms (Pilz et al., 2012). We conducted two experiments to explore factors that might determine when and if object-based attention effects are observed, focusing on the degree to which the concreteness and realism of objects might contribute to these effects. We adapted the classic attention paradigm first reported by Egly, Driver, and Rafal (1994) by replacing abstract bar stimuli in some conditions with objects that were more concrete and familiar to participants: items of silverware. Furthermore, we varied the realism of these items of silverware, presenting either cartoon versions or photo-realistic versions. Contrary to predictions, increased realism did not increase the size of object-based effects. In fact, no clear object-based effects were observed in either experiment, consistent with previous failures to replicate these effects in similar paradigms. While object-based attention may exist, and may have important influences on how we parse the visual world, these and other findings suggest that the two-object paradigm typically relied upon to study object-based effects may not be the best paradigm to investigate these issues.

  17. Understanding health decisions using critical realism: home-dialysis decision-making during chronic kidney disease.

    PubMed

    Harwood, Lori; Clark, Alexander M

    2012-03-01

    Understanding health decisions using critical realism: home-dialysis decision-making during chronic kidney disease This paper examines home-dialysis decision making in people with Chronic Kidney Disease (CKD) from the perspective of critical realism. CKD programmes focus on patient education for self-management to delay the progression of kidney disease and the preparation and support for renal replacement therapy e.g.) dialysis and transplantation. Home-dialysis has clear health, societal and economic benefits yet service usage is low despite efforts to realign resources and educate individuals. Current research on the determinants of modality selection is superficial and insufficient to capture the complexities embedded in the process of dialysis modality selection. Predictors of home-dialysis selection and the effect of chronic kidney disease educational programmes provide a limited explanation of this experience. A re-conceptualization of the problem is required in order to fully understand this process. The epistemology and ontology of critical realism guides our knowledge and methodology particularly suited for examination of these complexities. This approach examines the deeper mechanisms and wider determinants associated with modality decision making, specifically who chooses home dialysis and under what circumstances. Until more is known regarding dialysis modality decision making service usage of home dialysis will remain low as interventions will be based on inadequate epistemology.

  18. Enantiomeric separation and determination of absolute stereochemistry of asymmetric molecules in drug discovery: building chiral technology toolboxes.

    PubMed

    McConnell, Oliver; Bach, Alvin; Balibar, Carl; Byrne, Neal; Cai, Yanxuan; Carter, Guy; Chlenov, Michael; Di, Li; Fan, Kristi; Goljer, Igor; He, Yanan; Herold, Don; Kagan, Michael; Kerns, Edward; Koehn, Frank; Kraml, Christina; Marathias, Vasilios; Marquez, Brian; McDonald, Leonard; Nogle, Lisa; Petucci, Christopher; Schlingmann, Gerhard; Tawa, Gregory; Tischler, Mark; Williamson, R Thomas; Sutherland, Alan; Watts, William; Young, Mairead; Zhang, Mei-Yi; Zhang, Yingru; Zhou, Dahui; Ho, Douglas

    2007-09-01

    The application of Chiral Technology, or the (extensive) use of techniques or tools for the determination of absolute stereochemistry and the enantiomeric or chiral separation of racemic small molecule potential lead compounds, has been critical to successfully discovering and developing chiral drugs in the pharmaceutical industry. This has been due to the rapid increase over the past 10-15 years in potential drug candidates containing one or more asymmetric centers. Based on the experiences of one pharmaceutical company, a summary of the establishment of a Chiral Technology toolbox, including the implementation of known tools as well as the design, development, and implementation of new Chiral Technology tools, is provided.

  19. Application of chiral gas chromatography with electroantennographic detection to the determination of the stereochemistry of a cockroach sex pheromone.

    PubMed

    Leal, W S; Shi, X; Liang, D; Schal, C; Meinwald, J

    1995-02-14

    The coupling of an electroantennographic detector to a chiral capillary gas chromatographic system provides a highly sensitive technique for the determination of pheromone stereochemistry. Electronic modification of the usual electroantennographic detector enables the detector to respond to the relatively broad peaks produced by chiral gas chromatographic systems. By using this methodology, supellapyrone, a female sex pheromone of the brownbanded cockroach Supella longipalpa (Orthoptera: Blattellidae), is shown to be 5-(2'R,4'R-dimethylheptanyl)-3-methyl-2H-pyran-2-one.

  20. Application of chiral gas chromatography with electroantennographic detection to the determination of the stereochemistry of a cockroach sex pheromone.

    PubMed Central

    Leal, W S; Shi, X; Liang, D; Schal, C; Meinwald, J

    1995-01-01

    The coupling of an electroantennographic detector to a chiral capillary gas chromatographic system provides a highly sensitive technique for the determination of pheromone stereochemistry. Electronic modification of the usual electroantennographic detector enables the detector to respond to the relatively broad peaks produced by chiral gas chromatographic systems. By using this methodology, supellapyrone, a female sex pheromone of the brownbanded cockroach Supella longipalpa (Orthoptera: Blattellidae), is shown to be 5-(2'R,4'R-dimethylheptanyl)-3-methyl-2H-pyran-2-one. PMID:7862628

  1. Absolute configuration of a chiral CHD group via neutron diffraction: confirmation of the absolute stereochemistry of the enzymatic formation of malic acid

    SciTech Connect

    Bau, R.; Brewer, I.; Chiang, M.Y.; Fujita, S.; Hoffman, J.; Watkins, M.I.; Koetzle, T.F.

    1983-09-30

    Neutron diffraction has been used to monitor the absolute stereochemistry of an enzymatic reaction. (-)(2S)malic-3-d acid was prepared by the action of fumarase on fumaric acid in D/sub 2/O. After a large number of cations were screened, it was found that (+)(R)..cap alpha..-phenylethylamine forms the large crystals necessary for a neutron diffraction analysis. The subsequent structure determination showed that (+)(R)..cap alpha..-phenylethylammonium (-)(2S)malate-3-d has an absolute configuration of R at the CHD site. This result confirms the absolute stereochemistry of fumarate-to-malate transformation as catalyzed by the enzyme fumarase.

  2. Alteration of Polyketide Stereochemistry from anti to syn by a Ketoreductase Domain Exchange in a Type I Modular Polyketide Synthase Subunit.

    PubMed

    Eng, Clara H; Yuzawa, Satoshi; Wang, George; Baidoo, Edward E K; Katz, Leonard; Keasling, Jay D

    2016-03-29

    Polyketide natural products have broad applications in medicine. Exploiting the modular nature of polyketide synthases to alter stereospecificity is an attractive strategy for obtaining natural product analogues with altered pharmaceutical properties. We demonstrate that by retaining a dimerization element present in LipPks1+TE, we are able to use a ketoreductase domain exchange to alter α-methyl group stereochemistry with unprecedented retention of activity and simultaneously achieve a novel alteration of polyketide product stereochemistry from anti to syn. The substrate promiscuity of LipPks1+TE further provided a unique opportunity to investigate the substrate dependence of ketoreductase activity in a polyketide synthase module context.

  3. Structure-activity relationship studies on acremomannolipin A, the potent calcium signal modulator with a novel glycolipid structure 2: Role of the alditol side chain stereochemistry.

    PubMed

    Tsutsui, Nozomi; Tanabe, Genzoh; Gotoh, Genki; Morita, Nao; Nomura, Naohisa; Kita, Ayako; Sugiura, Reiko; Muraoka, Osamu

    2014-02-01

    Five alditol analogs 1b-1f of a novel glycolipid acremomannolipin A (1a), the potential Ca(2+) signal modulator isolated from Acremonium strictum, were synthesized by employing a stereoselective β-mannosylation of appropriately protected mannose with five hexitols with different stereochemistry, and their potential on modulating Ca(2+) signaling were evaluated. All these analogs were more potent compared to the original compound 1a, and proved that mannitol stereochemistry of 1a was not critical for the potent calcium signal modulating.

  4. Stereochemistry of N-Benzoyl-5-substituted-1-benzazepines Revisited: Synthesis of the Conformationally Biased Derivatives and Revision of the Reported Structure.

    PubMed

    Tabata, Hidetsugu; Yoneda, Tetsuya; Tasaka, Tomohiko; Ito, Shigekazu; Oshitari, Tetsuta; Takahashi, Hideyo; Natsugari, Hideaki

    2016-04-15

    The syn (aR*,5R*) and anti (aS*,5R*) diastereomers of N-benzoyl-C5-substituted-1-benzazepines originating in the chiralities at C5 and the Ar-N(C═O) axis were first stereoselectively synthesized by biasing the conformation with a substituent at C6 and C9, respectively. Detailed examination of the stereochemistry (i.e., conformation and configuration) of these N-benzoyl-1-benzazepines by X-ray crystallographic analysis, VT NMR, and DFT calculations revealed new physicochemical aspects of these heterocycles including revision of the stereochemistry previously reported.

  5. Geological realism in hydrogeological and geophysical inverse modeling: A review

    NASA Astrophysics Data System (ADS)

    Linde, Niklas; Renard, Philippe; Mukerji, Tapan; Caers, Jef

    2015-12-01

    Scientific curiosity, exploration of georesources and environmental concerns are pushing the geoscientific research community toward subsurface investigations of ever-increasing complexity. This review explores various approaches to formulate and solve inverse problems in ways that effectively integrate geological concepts with geophysical and hydrogeological data. Modern geostatistical simulation algorithms can produce multiple subsurface realizations that are in agreement with conceptual geological models and statistical rock physics can be used to map these realizations into physical properties that are sensed by the geophysical or hydrogeological data. The inverse problem consists of finding one or an ensemble of such subsurface realizations that are in agreement with the data. The most general inversion frameworks are presently often computationally intractable when applied to large-scale problems and it is necessary to better understand the implications of simplifying (1) the conceptual geological model (e.g., using model compression); (2) the physical forward problem (e.g., using proxy models); and (3) the algorithm used to solve the inverse problem (e.g., Markov chain Monte Carlo or local optimization methods) to reach practical and robust solutions given today's computer resources and knowledge. We also highlight the need to not only use geophysical and hydrogeological data for parameter estimation purposes, but also to use them to falsify or corroborate alternative geological scenarios.

  6. Z-sinapinic acid: the change of the stereochemistry of cinnamic acids as rational synthesis of a new matrix for carbohydrate MALDI-MS analysis.

    PubMed

    Salum, María L; Itovich, Lucia M; Erra-Balsells, Rosa

    2013-11-01

    Successful application of matrix-assisted laser desorption/ionization (MALDI) MS started with the introduction of efficient matrices such as cinnamic acid derivatives (i.e. 3,5-dimethoxy-4-hydroxycinnamic acid, SA; α-cyano-4-hydroxycinnamic acid). Since the empirical founding of these matrices, other commercial available cinnamic acids with different nature and location of substituents at benzene ring were attempted. Rational design and synthesis of new cinnamic acids have been recently described too. Because the presence of a rigid double bond in its molecule structure, cinnamic acids can exist as two different geometric isomers, the E-form and Z-form. Commercial available cinnamic acids currently used as matrices are the geometric isomers trans or E (E-cinnamic and trans-cinnamic acids). As a new rational design of MALDI matrices, Z-cinnamic acids were synthesized, and their properties as matrices were studied. Their performance was compared with that of the corresponding E-isomer and classical crystalline matrices (3,5-dihydroxybenzoic acid; norharmane) in the analysis of neutral/sulfated carbohydrates. Herein, we demonstrate the outstanding performance for Z-SA. Sulfated oligosaccharides were detected in negative ion mode, and the dissociation of sulfate groups was almost suppressed. Additionally, to better understand the quite different performance of each geometric isomer as matrix, the physical and morphological properties as well as the photochemical stability in solid state were studied. The influence of the E/Z photoisomerization of the matrix during MALDI was evaluated. Finally, molecular modeling (density functional theory study) of the optimized geometry and stereochemistry of E-cinnamic and Z-cinnamic acids revealed some factors governing the analyte-matrix interaction.

  7. Analysis of stereochemistry and biosynthesis of epicatechin in tea plants by chiral phase high performance liquid chromatography.

    PubMed

    Qian, Yumei; Zhao, Xianqian; Zhao, Lei; Cui, Lilan; Liu, Li; Jiang, Xiaolan; Liu, Yajun; Gao, Liping; Xia, Tao

    2015-12-01

    Tea (Camellia sinensis) is rich in flavan-3-ols (catechins), especially epicatechin (EC), which is the predominant extension unit of polymeric proanthocyanidins (PAs). However, studies assessing EC's stereochemistry are scarce. Here, a high performance liquid chromatography column using amylose tris-(3, 5-dimethylphenylcarbamate) immobilized on silica-gel as chiral stationary phases (CSPs) was applied to explore its stereochemistry and biosynthetic pathway in tea plants. The results revealed (-)-epicatechin [(-)-EC] was the predominant di-hyroxy-non-galloylated-catechins, while (+)-epicatechin [(+)-EC] was not detected. Interestingly, (-)-EC was the only product obtained from cyanidin using the partially purified native C. sinensis anthocyanidin reductase (CsANR) in the presence of reduction nicotinamide adenine dinucleotide phosphate (NADPH); meanwhile, (+)-EC was the main product using recombinant CsANR in the same conditions. In addition, (-)-EC could be obtained from (+)-catechin [(+)-C] using recombinant CsANR, which displayed C3-epimerase activity in the presence of oxidation nicotinamide adenine dinucleotide phosphate (NADP(+)). But the partially purified native CsANR did not possess this function. Finally, (-)-EC could result from the de-gallate acid reaction of epicatechin gallate (ECG) catalyzed by a novel partially purified native galloylated catechins hydrolase (GCH) from tea leaves. In summary, (-)-EC is likely the product of native protein from the tea plants, and (+)-EC is only produced in a reaction catalyzed by recombinant CsANR in vitro.

  8. Theoretical study on the mechanism and stereochemistry of the cinchona-thiourea organocatalytic hydrophosphonylation of an α-ketoester.

    PubMed

    Li, Weiyi; Huang, Dongfeng; Lv, Yajing

    2013-11-21

    The mechanism and stereochemistry of the hydrophosphonylation of an α-ketoester with dimethylphosphonate (DMHP) catalyzed by a thiourea-cinchona organocatalyst have been studied by the ONIOM method. The calculations show that the catalytic cycle is a three-step process, including the deprotonation of DMHP, C-P bond formation via nucleophilic addition and proton transfer with the regeneration of the catalyst. The deprotonation of DMHP mediated by the basicity of the quinuclidine nitrogen atom is the rate-determining step for the entire reaction. The activation of the α-ketoester by the thiourea or protonated cinchona moiety of the bifunctional catalyst is comparatively investigated, and the former is energy-preferred. AIM combined with NBO analysis indicate that the multiple hydrogen bonds play essential roles in activating substrates, facilitating charge transfer and stabilizing transition states and intermediates. The stereochemistry of the reaction is controlled by the C-P bond formation step and originated from the chiral induction of the multiple hydrogen-bonding interactions. The bulkier substituent groups on the chiral scaffold of the catalyst may increase rigidity of the catalyst and the asymmetric induction to the substrates. The calculations predict that alkyl substituted α-ketoesters might also be converted to chiral α-hydroxyl phosphonates with high enantioselectivity.

  9. Composition and stereochemistry of ephedrine alkaloids accumulation in Ephedra sinica Stapf.

    PubMed

    Krizevski, Raz; Bar, Einat; Shalit, Or; Sitrit, Yaron; Ben-Shabat, Shimon; Lewinsohn, Efraim

    2010-06-01

    Ephedra sinica Stapf (Ephedraceae) is a widely used Chinese medicinal plant (Chinese name: Ma Huang). The main active constituents of E. sinica are the unique and taxonomically restricted adrenergic agonists phenylpropylamino alkaloids, also known as ephedrine alkaloids: (1R,2S)-norephedrine (1S,2S)-norpseudoephedrine, (1R,2S)-ephedrine, (1S,2S)-pseudoephedrine, (1R,2S)-N-methylephedrine and (1S,2S)-N-methylpseudoephedrine. GC-MS analysis of freshly picked young E. sinica stems enabled the detection of 1-phenylpropane-1,2-dione and (S)-cathinone, the first two putative committed biosynthetic precursors to the ephedrine alkaloids. These metabolites are only present in young E. sinica stems and not in mature stems or roots. The related Ephedra foemina and Ephedra foliata also lack ephedrine alkaloids and their metabolic precursors in their aerial parts. A marked diversity in the ephedrine alkaloids content and stereochemical composition in 16 different E. sinica accessions growing under the same environmental conditions was revealed, indicating genetic control of these traits. The accessions can be classified into two groups according to the stereochemistry of the products accumulated: a group that displayed only 1R stereoisomers, and a group that displayed both 1S and 1R stereoisomers. (S)-cathinone reductase activities were detected in E. sinica stems capable of reducing (S)-cathinone to (1R,2S)-norephedrine and (1S,2S)-norpseudoephedrine in the presence of NADH. The proportion of the diastereoisomers formed varied according to the accession tested. A (1R,2S)-norephedrine N-methyltransferase capable of converting (1R,2S)-norephedrine to (1R,2S)-ephedrine in the presence of S-adenosylmethionine (SAM) was also detected in E. sinica stems. Our studies further support the notion that 1-phenylpropane-1,2-dione and (S)-cathinone are biosynthetic precursors of the ephedrine alkaloids in E. sinica stems and that the activity of (S)-cathinone reductases directs and

  10. Woodward-Hoffmann's Stereochemistry of Electrocyclic Reactions: From Day 1 to the JACS Receipt Date (May 5, 1964 to November 30, 1964).

    PubMed

    Seeman, Jeffrey I

    2015-12-04

    The publication in January 1965 of the first Woodward-Hoffmann paper, The Stereochemistry of Electrocyclic Reactions, ushered into organic chemistry both an explanation of the stereochemistry and "allowedness" or "forbiddenness" of concerted reactions and an impetus for untold numbers of research projects. In the current paper, details of the collaboration between R. B. Woodward and R. Hoffmann, from when they first met to discuss the solution to the "no-mechanism problem" to the date their first paper was received in the offices of the Journal of the American Chemical Society, will be discussed and analyzed. The primary focus will be on the historically relevant extant documents from the early 1960s. These include Hoffmann's laboratory notebooks describing his research, including his extended Hückel calculations used to explain and predict the stereochemistry of electrocyclic reactions. Drafts of the Stereochemistry of Electrocyclic Reactions paper and letters and notes by Woodward, Jerome Berson, and others will further illuminate the development of this first Woodward-Hoffmann paper.

  11. Assignment Of Hexuronic Acid Stereochemistry In Synthetic Heparan Sulfate Tetrasaccharides With 2-O-Sulfo Uronic Acids Using Electron Detachment Dissociation.

    PubMed

    Agyekum, Isaac; Patel, Anish B; Zong, Chengli; Boons, Geert-Jan; Amster, Jonathan

    2015-11-15

    The present work focuses on the assignment of uronic acid stereochemistry in heparan sulfate (HS) oligomers. The structural elucidation of HS glycosaminoglycans is the subject of considerable importance due to the biological and biomedical significance of this class of carbohydrates. They are highly heterogeneous due to their non-template biosynthesis. Advances in tandem mass spectrometry activation methods, particularly electron detachment dissociation (EDD), has led to the development of methods to assign sites of sulfo modification in glycosaminoglycan oligomers, but there are few reports of the assignment of uronic acid stereochemistry, necessary to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA). Whereas preceding studies focused on uronic acid epimers with no sulfo modification, the current work extends the assignment of the hexuronic acid stereochemistry to 2-O-sulfo uronic acid epimeric tetrasaccharides. The presence of a 2-O-sulfo group on the central uronic acid was found to greatly influence the formation of B3, C2, Z2, and Y1 ions in glucuronic acid and Y2 and (1,5)X2 for iduronic acid. The intensity of these peaks can be combined to yield a diagnostic ratios (DR), which can be used to confidently assign the uronic acid stereochemistry.

  12. Prediction and determination of the stereochemistry of the 1,3,5-trimethyl-substituted alkyl chain in verucopeptin, a microbial metabolite.

    PubMed

    Yoshimura, Aya; Kishimoto, Shinji; Nishimura, Shinichi; Otsuka, Saori; Sakai, Yuki; Hattori, Akira; Kakeya, Hideaki

    2014-08-01

    For the prediction of the relative stereochemistry of 1,3-dimethyl substitution in alkyl chains, a simple approach based on (1)H NMR data was recently proposed; Δδ values of methylene protons located between methyl-substituted methine carbons can be diagnostic for predicting it. Here we applied this empirical "geminal proton rule" to verucopeptin, a lipopeptide from Streptomyces sp. To determine the absolute stereochemistry of the 1,3,5-trimethyl-substituted alkyl chain in verucopeptin, we converted the corresponding alkyl chain to a carboxylic acid by oxidative cleavage. The geminal proton rule clearly predicted the relative stereochemistry as 31S*,33S*,35R*. This prediction was definitely confirmed by synthesizing four possible diastereomers and comparing their NMR spectra. Furthermore, we reinvestigated the geminal proton rule using reported compounds and our synthesized compounds. Our result strongly suggests that the rule was solid, at least for predicting the stereochemistry of 2,4-dimethylated and 2,4,6-trimethylated fatty acids.

  13. Design and Implementation of a Self-Directed Stereochemistry Lesson Using Embedded Virtual Three-Dimensional Images in a Portable Document Format

    ERIC Educational Resources Information Center

    Cody, Jeremy A.; Craig, Paul A.; Loudermilk, Adam D.; Yacci, Paul M.; Frisco, Sarah L.; Milillo, Jennifer R.

    2012-01-01

    A novel stereochemistry lesson was prepared that incorporated both handheld molecular models and embedded virtual three-dimensional (3D) images. The images are fully interactive and eye-catching for the students; methods for preparing 3D molecular images in Adobe Acrobat are included. The lesson was designed and implemented to showcase the 3D…

  14. Representational Realism, Closed Theories and the Quantum to Classical Limit

    NASA Astrophysics Data System (ADS)

    de Ronde, Christian

    In this chapter, we discuss the representational realist stance as a pluralistontic approach to inter-theoretic relationships. Our stance stresses the fact that physical theories require the necessary consideration of a conceptual level of discourse which determines and configures the specific field of phenomena discussed by each particular theory. We will criticize the orthodox line of research which has grounded the analysis about QM in two (Bohrian) metaphysical presuppositions - accepted in the present as dogmas that all interpretations must follow. We will also examine how the orthodox project of "bridging the gap" between the quantum and the classical domains has constrained the possibilities of research, producing only a limited set of interpretational problems which only focus in the justification of "classical reality" and exclude the possibility of analyzing the possibilities of non-classical conceptual representations of QM. The representational realist stance introduces two new problems, namely, the superposition problem and the contextuality problem, which consider explicitly the conceptual representation of orthodox QM beyond the mere reference to mathematical structures and measurement outcomes. In the final part of the chapter, we revisit, from representational realist perspective, the quantum to classical limit and the orthodox claim that this inter-theoretic relation can be explained through the principle of decoherence.

  15. Realism, instrumentalism, and scientific symbiosis: psychological theory as a search for truth and the discovery of solutions.

    PubMed

    Cacioppo, John T; Semin, Gün R; Berntson, Gary G

    2004-01-01

    Scientific realism holds that scientific theories are approximations of universal truths about reality, whereas scientific instrumentalism posits that scientific theories are intellectual structures that provide adequate predictions of what is observed and useful frameworks for answering questions and solving problems in a given domain. These philosophical perspectives have different strengths and weaknesses and have been regarded as incommensurate: Scientific realism fosters theoretical rigor, verifiability, parsimony, and debate, whereas scientific instrumentalism fosters theoretical innovation, synthesis, generativeness, and scope. The authors review the evolution of scientific realism and instrumentalism in psychology and propose that the categorical distinction between the 2 is overstated as a prescription for scientific practice. The authors propose that the iterative deployment of these 2 perspectives, just as the iterative application of inductive and deductive reasoning in science, may promote more rigorous, integrative, cumulative, and useful scientific theories.

  16. Back- and fore-grounding ontology: exploring the linkages between critical realism, pragmatism, and methodologies in health & rehabilitation sciences.

    PubMed

    DeForge, Ryan; Shaw, Jay

    2012-03-01

    Back- and fore-grounding ontology: exploring the linkages between critical realism, pragmatism, and methodologies in health & rehabilitation sciences As two doctoral candidates in a health and rehabilitation sciences program, we describe in this paper our respective paradigmatic locations along a quite nonlinear ontological-epistemological-axiological-methodological chain. In a turn-taking fashion, we unpack the tenets of critical realism and pragmatism, and then trace the linkages from these paradigmatic locations through to the methodological choices that address a community-based research problem. Beyond serving as an answer to calls for academics in training to demonstrate philosophical-theoretical-methodological integrity and coherence in their scholarship, this paper represents critical realism and its fore-grounding of a deeply stratified ontology in reflexive relation to pragmatism and its back-grounding of ontology. We conclude by considering the merits and challenges of conducting research from within singular versus proliferate paradigmatic perspectives.

  17. Invited commentary: On the future of social epidemiology--a case for scientific realism.

    PubMed

    Muntaner, Carles

    2013-09-15

    In their article in this issue of the Journal (Am J Epidemiol. 2013;178(6):843-849), Galea and Link identify important heuristics for our discipline. In this commentary, I build upon their ideas by arguing that (1) social epidemiology has become an Asian, European, Latin American, and African rather than just North American endeavor, (2) realism is better suited to social epidemiology than positivism, (3) more work on social mechanisms (social class relations, racial discrimination) is needed to increase the explanatory power of social epidemiology, (4) increased attention on (social) causal models will generate more innovative social interventions, and (5) social interventions should be conducted in full partnerships with affected populations.

  18. The effects of advice and "try more" instructions on improving realism of confidence.

    PubMed

    Buratti, Sandra; Allwood, Carl Martin

    2013-09-01

    This study investigated whether participants can improve the accuracy of their confidence judgments by making second-order judgments, and whether advice (attend both to correct and incorrect items and consider the remember/know quality of the item), and "try more" instructions can help increase participants' accuracy. The participants (n=220) made confidence judgments of their answers to 50 recall questions on a video clip. Next, all the participants were asked to try to increase the accuracy of their confidence judgments by modifying those they believed showed poor realism. Although the participants did increase the accuracy of their confidence judgments, neither the advice nor the "try more" instructions improved their accuracy.

  19. Can virtual reality increase the realism of role plays used to teach college women sexual coercion and rape-resistance skills?

    PubMed

    Jouriles, Ernest N; McDonald, Renee; Kullowatz, Antje; Rosenfield, David; Gomez, Gabriella S; Cuevas, Anthony

    2009-12-01

    The present study evaluated whether virtual reality (VR) can enhance the realism of role plays designed to help college women resist sexual attacks. Sixty-two female undergraduate students were randomly assigned to either the Role Play (RP) or Virtual Role Play (VRP) conditions, which were differentiated only by the use of VR technology in the VRP condition. A multimethod assessment strategy was used to evaluate the effects of VR on the experienced realism of sexually threatening role plays. Realism was assessed by participant self-reports of negative affect and perceptions of realism, direct observation of participants' verbal displays of negative affect during the role plays, and measurements of participant heart rate during the role plays. Results indicated that VR can indeed heighten the realism of sexually threatening role plays. Discussion focuses on issues regarding the use of VR-enhanced role plays for helping college women resist sexual attacks.

  20. Acid catalyzed alcoholysis of sulfinamides: unusual stereochemistry, kinetics and a question of mechanism involving sulfurane intermediates and their pseudorotation.

    PubMed

    Bujnicki, Bogdan; Drabowicz, Józef; Mikołajczyk, Marian

    2015-02-11

    The synthesis of optically active sulfinic acid esters has been accomplished by the acid catalyzed alcoholysis of optically active sulfinamides. Sulfinates are formed in this reaction with a full or predominant inversion of configuration at chiral sulfur or with predominant retention of configuration. The steric course of the reaction depends mainly on the size of the dialkylamido group in the sulfinamides and of the alcohols used as nucleophilic reagents. It has been found that bulky reaction components preferentially form sulfinates with retention of configuration. It has been demonstrated that the stereochemical outcome of the reaction can be changed from inversion to retention and vice versa by adding inorganic salts to the acidic reaction medium. The unusual stereochemistry of this typical bimolecular nucleophilic substitution reaction, as confirmed by kinetic measurements, has been rationalized in terms of the addition-elimination mechanism, A-E, involving sulfuranes as intermediates which undergo pseudorotations.

  1. Classroom Enters the Courtroom: Stereochemistry of SN1 and SN2 Reactions in Enantiomer Patent Litigations of the Antidepressant Escitalopram.

    PubMed

    Michman, Elisheva; Agranat, Israel

    2016-01-01

    The role of elementary stereochemistry is illustrated in the patent litigations of the blockbuster antidepressant drug escitalopram oxalate. An undergraduate student of organic chemistry would recognize the stereochemical courses of the intramolecular SN 2 and SN 1 reactions of the single-enantiomer (S)-diol intermediate in the synthesis of the blockbuster antidepressant drug escitalopram oxalate: retention of configuration of the chiral carbon atom under basic conditions and racemization under acidic conditions, respectively. He/she, in searching for a stereoselective ring-closure reaction of the enantiomeric diol, will think of an SN 2 reaction in a basic medium. From these points of view, the process claim in the enantiomer patents of escitalopram is obvious/lacks an inventive step. An organic chemistry examination problem based on this scenario is offered.

  2. Synthesis and Structural Properties of Aza[n]helicene Platinum Complexes: Control of Cis and Trans Stereochemistry.

    PubMed

    Mendola, Daniele; Saleh, Nidal; Hellou, Nora; Vanthuyne, Nicolas; Roussel, Christian; Toupet, Loïc; Castiglione, Franca; Melone, Federica; Caronna, Tullio; Fontana, Francesca; Martí-Rujas, Javier; Parisini, Emilio; Malpezzi, Luciana; Mele, Andrea; Crassous, Jeanne

    2016-03-07

    The synthesis and structural characterization of azahelicene platinum complexes obtained from cis-PtCl2(NCEt)(PPh3) and from ligands that differ in terms of both the position of the nitrogen atom and the number of fused rings are reported. These square-planar complexes of the general formula PtCl2(nHm)(PPh3) (n = 4, 5; m = 5, 6) display mainly a cis configuration. However, by X-ray crystallographic analysis, we show that for both PtCl2(4H6)(PPh3) and PtCl2(5H6)(PPh3) there is chirality control of the cis/trans stereochemistry. Indeed, starting from a racemic mixture of aza[6]helicene, platinum complexes with a cis configuration are invariably obtained, and the more thermodynamically stable trans isomers are formed when using enantiopure ligands. We further corroborated these results by NMR analysis in solution.

  3. Anisotropy effect of three-membered rings in (1)H NMR spectra: quantification by TSNMRS and assignment of the stereochemistry.

    PubMed

    Kleinpeter, Erich; Krüger, Stefanie; Koch, Andreas

    2015-05-07

    The spatial magnetic properties (through space NMR shieldings, TSNMRSs) of cyclopropane; of the heteroanalogous oxirane, thiirane, and aziridine; and of various substituted mono-, dis-, and tris-cyclic analogues have been computed by the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept and visualized as iso-chemical-shielding surfaces (ICSSs) of various size and direction. The TSNMRS values, thus obtained, can be employed to visualize the anisotropy (ring current) effect of the cyclopropane ring moiety. This approach has been employed to qualify and quantify substituent influences and contributions of appropriate ring heteroatoms O, NH, and S on the anisotropy (ring current) effect of three-membered ring moieties, and to assign the stereochemistry of mono-, bis-, and tris-cyclic structures containing cyclopropane as a structural element. Characteristic examples are included.

  4. Stereoselective Synthesis of 8,12-Furanoeudesmanes from Santonin. Absolute Stereochemistry of Natural Furanoeudesma-1,3-diene and Tubipofurane.

    PubMed

    Blay, Gonzalo; Cardona, Luz; García, Begoña; Pedro, José R.; Sánchez, Juan J.

    1996-05-31

    Ketobutenolide 3, easily obtained from santonin (1), has been transformed into two natural furanoeudesmanes 4 and 5, isolated from Commiphora molmol and Tubipora musica, respectively. trans- And cis-decalin systems were obtained by stereoselective reduction of the C(4)-C(5) double bond in 3 in the following way: hydrogenation of 3 over Pd/C followed by acidic treatment gave the cis isomer 10 as the major product; selective hydrogenation of the C(1)-C(2) double bond with the Wilkinson's catalyst followed by reduction with NaTeH yielded mainly the trans isomer 9. Compounds 9 and 10 were transformed into 4 and 5 in parallel sequences. Optical rotation and CD measurements of the synthetic products revealed that the stereochemistry of both natural products should be revised to their enantiomeric form.

  5. It's all about Me: methyl-induced control of coordination stereochemistry by a flexible tridentate N,C,N' ligand.

    PubMed

    Kariuki, Benson M; Platts, James A; Newman, Paul D

    2014-02-21

    A chiral, tridentate, pyridyl-functionalised NHC pro-ligand, S-L(Me)-H[PF₆], has been prepared diastereoselectively via a five step synthesis starting from 1R,3S-diamino-1,2,2-trimethylcyclopentane. The S prefix refers to the stereochemistry of a methyl substituted stereogenic carbon in one of the pyridyl arms which is generated by a stereoselective BH4(-) reduction of an imine precursor. The ligand has been coordinated to Rh(I) and Ir(I) to give trigonal bipyramidal complexes of the type [M(κ(3)-N,C,N'-S-L(Me))(1,5-COD)]PF6 (M = Rh, Ir) as single diastereomers. A combination of spectroscopic and X-ray techniques confirm the stereoselective formation of the thermodynamically preferred endo,endo isomer. Similar reactions with R,S-L(Me)-H[PF₆] gave a mixture of endo,endo-[M(κ(3)-N,C,N'-S-L(Me))(1,5-COD)](+) and exo,exo-[M(κ(3)-N,C,N'-R-L(Me))(1,5-COD)](+). The absolute configuration at the metal is, therefore, solely dictated by the stereochemistry of the single methylpyridyl carbon. The observation of stereoselection extends to the square planar Ni(II) complex [Ni(δ-κ(3)-N,C,N'-S-L(Me))Cl](+) which is isolated as one (δ) of the two possible conformational isomers. DFT studies have been employed to explain the observed stereoselectivity with the configurations observed in the solid state being confirmed as those of lowest energy.

  6. Structural investigations into the stereochemistry and activity of a phenylalanine-2,3-aminomutase from Taxus chinensis.

    PubMed

    Wybenga, Gjalt G; Szymanski, Wiktor; Wu, Bian; Feringa, Ben L; Janssen, Dick B; Dijkstra, Bauke W

    2014-05-20

    Phenylalanine-2,3-aminomutase (PAM) from Taxus chinensis, a 4-methylidene-imidazole-5-one (MIO)-dependent enzyme, catalyzes the reversible conversion of (S)-α-phenylalanine into (R)-β-phenylalanine via trans-cinnamic acid. The enzyme also catalyzes the direct addition of ammonia to trans-cinnamic acid, a reaction that can be used for the preparation of β-amino acids, which occur as frequent constituents of bioactive compounds. Different hypotheses have been formulated to explain the stereochemistry of the PAM-catalyzed reaction, but structural evidence for these hypotheses is lacking. Furthermore, it remains unclear how the PAM MIO group is formed from the three-amino acid (A-S-G) sequence motif. For these reasons, we elucidated PAM three-dimensional (3D) structures with a bound (R)-β-phenylalanine analogue and with bound trans-cinnamic acid. In addition, 3D structures of the (inactive) Y322A and N231A mutants of PAM were elucidated, which were found to be MIO-less. We conclude that the stereochemistry of the PAM-catalyzed reaction originates from the enzyme's ability to bind trans-cinnamic acid in two different orientations, with either the si,si face or the re,re face directed toward the MIO group, as evidenced by two distinct carboxylate binding modes. The results also suggest that the N231 side chain promotes MIO group formation by increasing the nucleophilicity of the G177 N atom through acidification of the amide proton.

  7. Stereochemistry and Mechanistic Insight in the [2(k)+2(i)+2(i)] Annulations of Ketenes and Imines.

    PubMed

    Yang, Zhanhui; He, Wei; Cheng, Baoxiang; Xu, Jiaxi

    2016-06-03

    The stereochemistry and mechanistic insight in the annulations of one ketene molecule with two imine molecules ([2(k)+2(i)+2(i)] annulation) are studied by using six-membered 3,4-dihydroisoquinoline as an imine probe. A concerted hetero-Diels-Alder cycloaddition mechanism is proposed to explain the stereochemical outcomes. In most cases, the zwitterionic 2-aza-1,3-butadiene-type intermediates, generated from ketenes and imines, undergo endo hetero-Diels-Alder cycloaddition with the second imine molecule. For ketenes with electron-donating substituents, (2,4)-cis-(4,5)-cis-[2(k)+2(i)+2(i)] annuladducts formed stereospecifically, while, for ketenes with electron-accepting substituents, (2,4)-cis-(4,5)-trans-[2(k)+2(i)+2(i)] annuladducts are generated stereospecifically. The [2(k)+2(i)+2(i)] annulations of aryloxyketenes and 3,4-dihydroisoquinoline give stereodivergent products due to the occurrence of the stepwise nucleophilic annulation. However, in the [2(k)+2(i)+2(i)] annulations of seven-membered cyclic imine dibenzo[b,f][1,4]oxazepine, the zwitterionic aza-butadiene-type intermediates exclusively undergo exo hetero-Diels-Alder cycloadditions with another molecule of imine to yield (2,4)-trans-(4,5)-trans-[2(k)+2(i)+2(i)] annuladducts stereospecifically, regardless of the ketene substituents. The mechanistic model not only discloses the nature of the [2(k)+2(i)+2(i)] annulations, but also can be used to explain and predict the stereochemistry of the [2(k)+2(i)+2(i)] annuladducts from different ketenes and imines.

  8. Depressive realism and attributional style: implications for individuals at risk for depression.

    PubMed

    Moore, Michael T; Fresco, David M

    2007-06-01

    Prior research has found that depressed individuals are more realistic in their interpretations of certain events than nondepressed individuals. However, the implications of this finding for the etiology of depressive disorders have never been clarified. The current investigation sought to remedy this situation by exploring realism in the context of a well-validated, cognitive diathesis-stress theory of the etiology of a subtype of depression: hopelessness theory (Abramson, L. Y., Metalsky, G. I., & Alloy, L. B. (1989). Hopelessness depression: A theory-based subtype of depression. Psychological Review, 96, 358-372). A sample of 239 college students, including groups of participants with depressogenic versus nondepressogenic attributional styles, recorded the causes they assigned to events; the extent to which their attributions were objectively realistic was evaluated. A comparison of the degree of objectivity was also made between dysphoric and nondysphoric individuals. Contrary to expectations derived from the depressive realism hypothesis, dysphoric individuals exhibited less realistic attributions as compared to nondysphoric individuals. Further, individuals at risk for depression evidenced a pessimistic bias, while individuals not at risk evidenced an optimistic bias.

  9. Perceived realism moderates the relation between sexualized media consumption and permissive sexual attitudes in Dutch adolescents.

    PubMed

    Baams, Laura; Overbeek, Geertjan; Dubas, Judith Semon; Doornwaard, Suzan M; Rommes, Els; van Aken, Marcel A G

    2015-04-01

    This study examined whether the development of sexualized media consumption and permissive sexual attitudes would be more strongly interrelated when adolescents perceived sexualized media images as highly realistic. We used data from a three-wave longitudinal sample of 444 Dutch adolescents aged 13-16 years at baseline. Results from parallel process latent growth modeling multigroup analyses showed that higher initial levels of sexualized media consumption were associated with higher initial level of permissive sexual attitudes. Moreover, increases of sexualized media consumption over time were associated with increases of permissive sexual attitudes over time. Considering the moderation by perceived realism, we found these effects only for those who perceived sexualized media as more realistic. Findings for male and female adolescents were similar except for the relations between initial levels and subsequent development. Among male adolescents who perceived sexualized media images to be realistic, higher initial levels of permissive sexual attitudes were related to subsequent less rapid development of sexualized media consumption. For male adolescents who perceived sexualized media to be less realistic, higher initial levels of sexualized media consumption were related to a subsequent less rapid development of permissive sexual attitudes. These relations were not found for female adolescents. Overall, our results suggest that, in male and female adolescents, those with a high level of perceived realism showed a correlated development of sexualized media consumption and permissive sexual attitudes. These findings point to a need for extended information on how to guide adolescents in interpreting and handling sexualized media in everyday life.

  10. Questioning the Value of Realism: Young Adults' Processing of Messages in Alcohol-Related Public Service Announcements and Advertising.

    ERIC Educational Resources Information Center

    Andsager, Julie L.; Austin, Erica Weintraub; Pinkleton, Bruce E.

    2001-01-01

    Finds that: (1) perceived realism and themes that students could identify with are important factors in increasing the salience and persuasiveness of alcohol-related public service announcements (PSAs) among undergraduate students; (2) realistic but logic-based PSAs were not as effective as unrealistic but enjoyable ads; and (3) low production…

  11. Women of ALA Youth Services and Professional Jurisdiction: Of Nightingales, Newberies, Realism, and the Right Books, 1937-1945.

    ERIC Educational Resources Information Center

    Jenkins, Christine A.

    1996-01-01

    Discussion of the female-intensive specialization of youth services librarianship and their role in the American Library Association focuses on their jurisdiction over the Newbery Medal. Topics include the question of realism in children's literature; the Sayers Institute; and evaluation criteria. Contains 65 references. (LRW)

  12. Impact of Dysphoria and Self-Consciousness on Perceptions of Social Competence: Test of the Depressive Realism Hypothesis

    ERIC Educational Resources Information Center

    Chau, Phuong M.; Milling, Leonard S.

    2006-01-01

    Depressive realism refers to a cognitive style wherein depressed people sometimes have more accurate perceptions of reality than nondepressed people. The notion of depressives being "sadder yet wiser" was controversial when first presented, and continues to be heavily debated. Self-perception studies provide maximum external validity,…

  13. Child and Adult Witnesses: The Effect of Repetition and Invitation-Probes on Free Recall and Metamemory Realism

    ERIC Educational Resources Information Center

    Knutsson, Jens; Allwood, Carl Martin; Johansson, Marcus

    2011-01-01

    Witnesses' event recall and the realism in their evaluation of the correctness of their recall are of great importance in forensic processes. These issues were investigated in the present study by use of calibration methodology. More specifically, we analyzed the effects of two recalls of the same event ("repetition") and of "probes"…

  14. Working with Cultural-Historical Activity Theory and Critical Realism to Investigate and Expand Farmer Learning in Southern Africa

    ERIC Educational Resources Information Center

    Mukute, Mutizwa; Lotz-Sisitka, Heila

    2012-01-01

    This article uses the theoretical and methodological tools of cultural historical activity theory and critical realism to examine three case studies of the introduction and expansion of sustainable agricultural practices in southern Africa. The article addresses relevant issues in the field of agricultural extension, which lacks a theoretical…

  15. How to constrain multi-objective calibrations using water balance components for an improved realism of model results

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate discharge simulation is one of the most common objectives of hydrological modeling studies. However, a good simulation of discharge is not necessarily the result of a realistic simulation of hydrological processes within the catchment. To enhance the realism of model results, we propose an ...

  16. The Effectiveness of Physical Models in Teaching Anatomy: A Meta-Analysis of Comparative Studies

    ERIC Educational Resources Information Center

    Yammine, Kaissar; Violato, Claudio

    2016-01-01

    There are various educational methods used in anatomy teaching. While three dimensional (3D) visualization technologies are gaining ground due to their ever-increasing realism, reports investigating physical models as a low-cost 3D traditional method are still the subject of considerable interest. The aim of this meta-analysis is to quantitatively…

  17. A high-performance liquid chromatography with circular dichroism detector for determination of stereochemistry of 6, 9-oxygen bridge dibenzocyclooctadiene lignans from kadsura coccinea.

    PubMed

    Zhu, Hui; Xu, Liang; Yang, Shi-Lin; Li, He-Ran

    2015-10-01

    The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chromatography using circular dichroism detection for the analysis of the stereochemistry. A new 6, 9-oxygen bridge dibenzocyclooctadiene lignans named Kadsulignan Q was firstly found with an S-biphenyl configuration. The other compound was identified as Kadsulignan L with an R- biphenyl configuration. In order to obtain kinetic data on their reversible interconversion, the stability was measured at different deuterated solvents such as deuterated methanol, deuterated chloroform and deuterated dimethylsulfoxide. The lignans were more unstable and converted more easily in deuterated methanol than in deuterated chloroform and deuterated dimethylsulfoxide.

  18. Computational and NMR Spectroscopic Evidence for Stereochemistry-Dependent Conformations of 2,2,6,6-Tetramethylpiperidinyl-Masked 1,2-Diols.

    PubMed

    Fought, Ellie L; Chatterjee, Shreyosree; Windus, Theresa L; Chen, Jason S

    2015-10-16

    2,2,6,6-Tetramethylpiperidinyl-masked 1,2-diols exhibited stereochemistry-dependent hydroxyl proton chemical shifts: ca. 7 ppm for the syn diastereomer and ca. 2 ppm for the anti diastereomer. A computational search for low energy geometries revealed that the syn isomer favors a six-membered ring hydrogen bond to nitrogen and the anti isomer favors a five-membered ring hydrogen bond to oxygen. The computed low energy conformations were found to have a large difference in hydroxyl proton shielding that was reflected in the experimental chemical shift difference. This chemical shift difference was observed in a broad range of solvents, and thus may be useful as a stereochemical probe. The stereochemistry-dependent conformation and chemical shift signature appeared to be due to a syn pentane interaction between the gem-dimethyl groups on the 2,2,6,6-tetramethylpiperidinyl moiety.

  19. A strict experimental test of macroscopic realism in a superconducting flux qubit

    NASA Astrophysics Data System (ADS)

    Knee, George C.; Kakuyanagi, Kosuke; Yeh, Mao-Chuang; Matsuzaki, Yuichiro; Toida, Hiraku; Yamaguchi, Hiroshi; Saito, Shiro; Leggett, Anthony J.; Munro, William J.

    2016-11-01

    Macroscopic realism is the name for a class of modifications to quantum theory that allow macroscopic objects to be described in a measurement-independent manner, while largely preserving a fully quantum mechanical description of the microscopic world. Objective collapse theories are examples which aim to solve the quantum measurement problem through modified dynamical laws. Whether such theories describe nature, however, is not known. Here we describe and implement an experimental protocol capable of constraining theories of this class, that is more noise tolerant and conceptually transparent than the original Leggett-Garg test. We implement the protocol in a superconducting flux qubit, and rule out (by ~84 s.d.) those theories which would deny coherent superpositions of 170 nA currents over a ~10 ns timescale. Further, we address the `clumsiness loophole' by determining classical disturbance with control experiments. Our results constitute strong evidence for the superposition of states of nontrivial macroscopic distinctness.

  20. Trick or treat? Muslim Thangals, psychologisation and pragmatic realism in northern Kerala, India.

    PubMed

    Lang, Claudia

    2014-12-01

    Thangals are an endogamous community in Kerala, India, of Yemeni heritage who claim direct descent from the Prophet Muhammad's family. Due to their sacrosanct status, many thangals work as religious healers and thus are part of the informal mental health care system in Northern Kerala. Using the case of one thangal healer as an illustration of the many ritual healers in Kerala who engage the modern discourse of psychology in their practices, I argue that the psychologisation of ritual healing is part of a wider trend: the increasing rationalisation and scientification of traditional medical practices, whereby an increasing number of traditional healers negotiate science, modernity and religion and position their practice within these contested fields. Based on the analysis of this thangal's healing practice in the local context of Northern Kerala, I further argue that in order to understand "ritual" healing, scholars should emphasise pragmatic realism more than doctrinal purity.

  1. A strict experimental test of macroscopic realism in a superconducting flux qubit.

    PubMed

    Knee, George C; Kakuyanagi, Kosuke; Yeh, Mao-Chuang; Matsuzaki, Yuichiro; Toida, Hiraku; Yamaguchi, Hiroshi; Saito, Shiro; Leggett, Anthony J; Munro, William J

    2016-11-04

    Macroscopic realism is the name for a class of modifications to quantum theory that allow macroscopic objects to be described in a measurement-independent manner, while largely preserving a fully quantum mechanical description of the microscopic world. Objective collapse theories are examples which aim to solve the quantum measurement problem through modified dynamical laws. Whether such theories describe nature, however, is not known. Here we describe and implement an experimental protocol capable of constraining theories of this class, that is more noise tolerant and conceptually transparent than the original Leggett-Garg test. We implement the protocol in a superconducting flux qubit, and rule out (by ∼84 s.d.) those theories which would deny coherent superpositions of 170 nA currents over a ∼10 ns timescale. Further, we address the 'clumsiness loophole' by determining classical disturbance with control experiments. Our results constitute strong evidence for the superposition of states of nontrivial macroscopic distinctness.

  2. Critical realism: distinguishing the psychological subjectivity of the analyst from epistemological subjectivism.

    PubMed

    Hanly, C; Hanly, M A

    2001-01-01

    To clarify the concepts of critical realism, subjectivity, and subjectivism, distinctions are drawn among ontological subjectivism, moral subjectivity, psychological subjectivity, and epistemological subjectivism. Psychological subjectivity, including the ongoing affective life of the analyst, is an essential aspect of the analyst's response to the patient, and may either facilitate or distort an adequate observation of transference and countertransference dynamics and of the psychic reality of the patient. Subjectivism in current psychoanalytic literature involves an argument that there is an "irreducible" subjectivity in the analyst, who is bound to see things from an incorrigibly personal point of view, such that there is no substantial subject-object differentiation between analyst and patient. Issues of authoritarianism in the analyst, or of pathological certainty, should not be confused with the issues of epistemological objectivism. The concept of critical realism or scientific objectivism includes the essential idea that there is no pure knowledge, no complete knowledge, that often evidence is insufficient for knowledge of some aspect of nature, and that care must be to taken understand what is sufficient knowledge in a given area, in this case clinical psychoanalysis. The question is raised whether "projective identification" makes the sorting out of "what comes from whom" impossible. It is argued that when free association is sufficiently facilitated, when there are enough corrections of the distortions wrought by transference and countertransference, when defenses are analyzed, and when sufficient subject-object differentiation is recovered, the analyst can get to know enough of the patient's psychic reality for the therapeutic and scientific purposes of psychoanalysis.

  3. Balancing practicality and hydrologic realism: Insights from applications of a parsimonious model of unsaturated-zone preferential flow

    NASA Astrophysics Data System (ADS)

    Mirus, B. B.; Perkins, K. S.; Nimmo, J. R.

    2011-12-01

    Simple assessments are often needed to inform local land-management decisions. Preferential flow, a crucial process in many land-management decisions, presents a considerable challenge to the parameterization and evaluation of commonly used hydrologic models. Traditional unsaturated flow theory (i.e., Richards equation) does not accurately represent the physics of preferential flow and often underestimates the arrival time and magnitude of fluxes when applied in situations where preferential flow is important. Another shortcoming of traditional modeling approaches is the considerable data required to characterize the distribution of subsurface hydraulic properties. A source-responsive model has been developed based on film-flow theory to provide more realistic approximations of unsaturated-zone preferential flow when limited data and site characterization are available. The term source-responsive is used to describe the sensitivity of preferential flow to changing conditions at the source of water input, which are typically better quantified than hydraulic properties. We present applications of this parsimonious model for sites in Idaho and Nevada with heterogeneous vadose zones (40 m and 1000 m in thickness, respectively) where radionuclide contamination poses a threat to groundwater quality. Despite differences in input data for each application, results from both applications provide reasonable flux estimates, which are useful for characterizing worst-case scenarios for advective transport of conservative contaminants. We contrast the results for the two applications in terms of the data employed for each and discuss the advantages of the model parameterization, which relies heavily on the quantity and timing of net infiltration. There are several opportunities for improvements in model performance, but these involve greater model complexity with a corresponding increase in free parameters and data requirements. The tradeoff between hydrologic realism and

  4. Significance of stereochemistry of 3'-terminal phosphorothioate-modified primer in DNA polymerase-mediated chain extension.

    PubMed

    Nawrot, Barbara; Paul, Natasha; Rebowska, Beata; Stec, Wojciech J

    2008-10-01

    Influence of stereochemistry of the 3'-terminal phosphorothioate (PS)-modified primers was studied in a single base extension (SBE) assay to evaluate any improvements in specificity. SBE reactions were catalyzed by members of the high fidelity Pfu family of DNA polymerases with (exo+) or without (exo-) 3' --> 5' exonucleolytic activity. The diastereomerically pure PS-labeled primers used in these studies were obtained either by the stereospecific chemical synthesis invented in our laboratory or by the more conventional ion-exchange chromatographic method for separation of a mixture of diastereomers (R(P) and S(P)). When the SBE reaction was performed in the presence of mispaired 2'-deoxyribonucleoside triphosphates (dNTPs), the "racemic" 3'-phosphorothioate primer mixture resulted in a lower level of 3' --> 5' exonuclease-mediated cleavage products in comparison to the SBE reactions carried out with the corresponding unmodified primer. When the diastereomerically pure RP 3'-phosphorothioate primer was examined, the results were largely the same as for the racemic 3'-phosphorothioate primer mixture. In contrast, a 3'-PS primer of S(P) configuration displayed significantly improved performance in the SBE reaction. This included the lack of 3' --> 5' proofreading products, less mispriming, and improved yield of incorporation of the correct nucleotide.

  5. Structure and stereochemistry of the base excision repair glycosylase MutY reveal a mechanism similar to retaining glycosidases

    PubMed Central

    Woods, Ryan D.; O'Shea, Valerie L.; Chu, Aurea; Cao, Sheng; Richards, Jody L.; Horvath, Martin P.; David, Sheila S.

    2016-01-01

    MutY adenine glycosylases prevent DNA mutations by excising adenine from promutagenic 8-oxo-7,8-dihydroguanine (OG):A mismatches. Here, we describe structural features of the MutY active site bound to an azaribose transition state analog which indicate a catalytic role for Tyr126 and approach of the water nucleophile on the same side as the departing adenine base. The idea that Tyr126 participates in catalysis, recently predicted by modeling calculations, is strongly supported by mutagenesis and by seeing close contact between the hydroxyl group of this residue and the azaribose moiety of the transition state analog. NMR analysis of MutY methanolysis products corroborates a mechanism for adenine removal with retention of stereochemistry. Based on these results, we propose a revised mechanism for MutY that involves two nucleophilic displacement steps akin to the mechanisms accepted for ‘retaining’ O-glycosidases. This new-for-MutY yet familiar mechanism may also be operative in related base excision repair glycosylases and provides a critical framework for analysis of human MutY (MUTYH) variants associated with inherited colorectal cancer. PMID:26673696

  6. Structure and stereochemistry of the base excision repair glycosylase MutY reveal a mechanism similar to retaining glycosidases.

    PubMed

    Woods, Ryan D; O'Shea, Valerie L; Chu, Aurea; Cao, Sheng; Richards, Jody L; Horvath, Martin P; David, Sheila S

    2016-01-29

    MutY adenine glycosylases prevent DNA mutations by excising adenine from promutagenic 8-oxo-7,8-dihydroguanine (OG):A mismatches. Here, we describe structural features of the MutY active site bound to an azaribose transition state analog which indicate a catalytic role for Tyr126 and approach of the water nucleophile on the same side as the departing adenine base. The idea that Tyr126 participates in catalysis, recently predicted by modeling calculations, is strongly supported by mutagenesis and by seeing close contact between the hydroxyl group of this residue and the azaribose moiety of the transition state analog. NMR analysis of MutY methanolysis products corroborates a mechanism for adenine removal with retention of stereochemistry. Based on these results, we propose a revised mechanism for MutY that involves two nucleophilic displacement steps akin to the mechanisms accepted for 'retaining' O-glycosidases. This new-for-MutY yet familiar mechanism may also be operative in related base excision repair glycosylases and provides a critical framework for analysis of human MutY (MUTYH) variants associated with inherited colorectal cancer.

  7. Collapsed bipolar glycolipids at the air/water interface: effect of the stereochemistry on the stretched/bent conformations.

    PubMed

    Jacquemet, Alicia; Terme, Nolwenn; Benvegnu, Thierry; Vié, Véronique; Lemiègre, Loïc

    2013-12-15

    This article describes a comparative study of several bipolar lipids derived from tetraether structures. The sole structural difference between the main two glycolipids is a unique stereochemical variation on a cyclopentyl ring placed in the middle of the lipids. We discuss the comparative results obtained at the air/water interface on the basis of tensiometry and ellipsometry. Langmuir-Blodgett depositions during lipid film compressions and decompressions were also analyzed by AFM. The lactosylated tetraether (bipolar) lipid structures involved the formation of highly stable multilayers, which are still present at 10 mN m(-1) during decompression. This study suggests also that the stereochemistry of a central cyclopentyl ring dramatically drives the conformation of the corresponding bipolar lipids. Both isomers (trans and cis) adopt a U-shaped (bent) conformation at the air/water interface but the trans cyclopentyl ring induces a much more frustration within this type of conformation. Consequently, this bipolar lipid (trans-tetraether) undergoes a flip of one polar head-group (lactosyl) leading to a stretched conformation during collapse.

  8. Stereochemistry of spiro-acetalized [60]fullerenes: how the exo and endo stereoisomers influence organic solar cell performance.

    PubMed

    Mikie, Tsubasa; Saeki, Akinori; Yamazaki, Yu; Ikuma, Naohiko; Kokubo, Ken; Seki, Shu

    2015-04-29

    Exploiting bis-addition products of fullerenes is a rational way to improve the efficiency of bulk heterojunction-type organic photovoltaic cells (OPV); however, this design inherently produces regio- and stereoisomers that may impair the ultimate performance and fabrication reproducibility. Here, we report unprecedented exo and endo stereoisomers of the spiro-acetalized [60]fullerene monoadduct with methyl- or phenyl-substituted 1,3-dioxane (SAF6). Although there is no chiral carbon in either the reagent or the fullerene, equatorial (eq) rather than axial (ax) isomers are selectively produced at an exo-eq:endo-eq ratio of approximately 1:1 and can be easily separated using silica gel column chromatography. Nuclear Overhauser effect measurements identified the conformations of the straight exo isomer and bent endo isomer. We discuss the origin of stereoselectivity, the anomeric effect, intermolecular ordering in the film state, and the performance of poly(3-hexylthiophene):substituted SAF6 OPV devices. Despite their identical optical and electrochemical properties, their solubilities and space-charge limited current mobilities are largely influenced by the stereoisomers, which leads to variation in the OPV efficiency. This study emphasizes the importance of fullerene stereochemistry for understanding the relationship between stereochemical structures and device output.

  9. Cell-penetrating compounds preferentially bind glycosaminoglycans over plasma membrane lipids in a charge density- and stereochemistry-dependent manner.

    PubMed

    Prevette, Lisa E; Benish, Nicolas C; Schoenecker, Amber R; Braden, Kristin J

    2015-12-01

    Cell-penetrating compounds (CPCs) are often conjugated to drugs and genes to facilitate cellular uptake. We hypothesize that the electrostatic interaction between the positively charged amines of the cell-penetrating compounds and the negatively charged glycosaminoglycans (GAGs) extending from cell surfaces is the initiating step in the internalization process. The interactions of generation 5 PAMAM dendrimer, Tat peptide and 25 kDa linear PEI with four different GAGs have been studied using isothermal titration calorimetry to elucidate structure-function relationships that could lead to improved drug and gene delivery methods to a wide variety of cell types. Detailed thermodynamic analysis has determined that CPC-GAG binding constants range from 8.7×10(3) to 2.4×10(6)M(-1) and that affinity is dependent upon GAG charge density and stereochemistry and CPC molecular weight. The effect of GAG composition on affinity is likely due to hydrogen bonding between CPC amines and amides and GAG hydroxyl and amine groups. These results were compared to the association of CPCs with lipid vesicles of varying composition as model plasma membranes to finally clarify the relative importance of each cell surface component in initial cell recognition. CPC-lipid affinity increases with anionic lipid content, but GAG affinity is higher for all cell-penetrating compounds, confirming the role these heterogeneous polysaccharides play in cellular association and clustering.

  10. Protochlorophyllide reductase. 1. Determination of the regiochemistry and the stereochemistry of the reduction of protochlorophyllide to chlorophyllide

    SciTech Connect

    Begley, T.P.; Young, H. )

    1989-04-12

    It has been estimated that over 1 billion tons of chlorophyll are synthesized in the biosphere each year. Although the chlorophyll biosynthetic pathway has been the subject of intense investigation over the 50 years, much remains to be discovered. One promising area of investigation is the remarkable color change, from yellow to green, that occurs when dark-grown plants are exposed to light. This greening reaction involves the reduction of protochlorophyllide to chlorophyllide and is a key regulatory step both in the biosynthesis of chlorophyll and in the development of the chloroplast. This reaction is catalyzed by the enzyme protochlorophyllide reductase and is of interest because it is one of only two known light-requiring enzymatic reactions. The enzyme has been purified from oats, barley, wheat, and squash. It is an unstable membrane-bound protein of 37,000 D molecular weight. The quantum yield for protochlorophyllide reduction in barley seedlings is 0.4 and the action spectrum for the reaction in corn seedlings follows the absorption spectrum of protochlorophyllide. As the first step in our mechanistic investigation of this important reaction, we have determined the regiochemistry and the stereochemistry of the reduction catalyzed by the oats enzyme. On the basis of this information, we propose a model for the active site of the enzyme.

  11. Effect of Stereochemistry on Directed Self-Assembly of Poly(styrene-b-lactide) Films on Chemical Patterns

    SciTech Connect

    Li, Xiao; Liu, Yadong; Wan, Lei; Li, Zhaolei; Suh, Hyoseon; Ren, Jiaxing; Ocola, Leonidas E.; Hu, Wenbing; Ji, Shengxiang; Nealey, Paul F.

    2016-03-15

    We demonstrated here for the first time that the stereochemistry of polylactide (PLA) blocks affected the assembly behaviors of PS-b-PLA on chemical patterns. Two PS-b-PLA block copolymers, where the PLA block is either racemic (PDLLA) or left-handed (PLLA), were synthesized and directed to assemble on chemical patterns with a wide range of L-s/L-o. PS-b-PDLLA was stretched up to 70% on chemical patterns, while PS-b-PLLA was only stretched by 20%. The assembly behavior of PS-b-PDLLA was different from AB diblock copolymer, but similar to that of ABA triblock copolymer. The high stretchability might be attributed to the formation of stereocomplexes in PDLLA blocks. Compared to ABA triblock copolymers, stereocomplexed diblock copolymers have much faster assembly kinetics. This observation provides a new concept to achieve large process windows by the introduction of specific interactions, for example, H-bonding, supramolecular interaction, and sterecomplexation, between polymer chains.

  12. Theoretical study of the potential energy surface governing the stereochemistry in ClC sub 2 H sub 4 reactions

    SciTech Connect

    Engels, B.; Peyerimhoff, S.D. ); Skell, P.S. )

    1990-02-22

    Large-scale multireference configuration interaction calculations in a double-{xi}-type AO basis including polarization functions are carried out for the potential surface of the ClC{sub 2}H{sub 4} system. The charge distribution for various extreme points of the surface is discussed. The absolute minimum is found for an asymmetric ClC{sub 2}H{sub 4} structure. The symmetrical bridged nuclear conformation is also found to be stable with respect to dissociation into Cl + C{sub 2}H{sub 4}. The activation energy for rotation about the C-C axis is calculated to be around 18 kJ/mol, which is comparable to that for the 1,2 migration (around 26 kJ mol). The stereochemistry is governed by the fact that addition of Cl to C{sub 2}H{sub 4} (or dissociation) is a two-step reaction proceeding through a symmetrical intermediate. The direct addition pathway possesses a small barrier of about 8 kJ/mol.

  13. Versatile transformations of hydrocarbons in anaerobic bacteria: substrate ranges and regio- and stereo-chemistry of activation reactions†

    PubMed Central

    Jarling, René; Kühner, Simon; Basílio Janke, Eline; Gruner, Andrea; Drozdowska, Marta; Golding, Bernard T.; Rabus, Ralf; Wilkes, Heinz

    2015-01-01

    Anaerobic metabolism of hydrocarbons proceeds either via addition to fumarate or by hydroxylation in various microorganisms, e.g., sulfate-reducing or denitrifying bacteria, which are specialized in utilizing n-alkanes or alkylbenzenes as growth substrates. General pathways for carbon assimilation and energy gain have been elucidated for a limited number of possible substrates. In this work the metabolic activity of 11 bacterial strains during anaerobic growth with crude oil was investigated and compared with the metabolite patterns appearing during anaerobic growth with more than 40 different hydrocarbons supplied as binary mixtures. We show that the range of co-metabolically formed alkyl- and arylalkyl-succinates is much broader in n-alkane than in alkylbenzene utilizers. The structures and stereochemistry of these products are resolved. Furthermore, we demonstrate that anaerobic hydroxylation of alkylbenzenes does not only occur in denitrifiers but also in sulfate reducers. We propose that these processes play a role in detoxification under conditions of solvent stress. The thermophilic sulfate-reducing strain TD3 is shown to produce n-alkylsuccinates, which are suggested not to derive from terminal activation of n-alkanes, but rather to represent intermediates of a metabolic pathway short-cutting fumarate regeneration by reverse action of succinate synthase. The outcomes of this study provide a basis for geochemically tracing such processes in natural habitats and contribute to an improved understanding of microbial activity in hydrocarbon-rich anoxic environments. PMID:26441848

  14. Reactions to safer-sex public service announcement message features: attention, perceptions of realism, and cognitive responses.

    PubMed

    Van Stee, Stephanie K; Noar, Seth M; Allard, Suzanne; Zimmerman, Rick; Palmgreen, Philip; McClanahan, Kitty

    2012-11-01

    For this article, we conducted a qualitative investigation of participants' reactions to five televised public service announcements (PSAs) that were aired as part of a large safer-sex mass media campaign to increase condom use among young adults. We conducted qualitative interviews (N = 139) to determine which features of PSAs participants thought were most effective in terms of attention and recall, perceived realism of characters and situations, and cognitive responses. Our analysis of the results highlights the importance of high-sensation-value messages for gaining attention as well as the critical role of personal relevance for enhancing perceptions of realism. Cognitive responses to PSAs were mostly positive, but there was evidence of third-person effects. That is, many participants indicated that the safer-sex messages were important for other people but not for themselves. We discuss the implications of our results for designing PSAs that are attention-catching, realistic, and persuasive.

  15. Beyond Gisin's Theorem and its Applications: Violation of Local Realism by Two-Party Einstein-Podolsky-Rosen Steering.

    PubMed

    Chen, Jing-Ling; Su, Hong-Yi; Xu, Zhen-Peng; Wu, Yu-Chun; Wu, Chunfeng; Ye, Xiang-Jun; Żukowski, Marek; Kwek, L C

    2015-06-25

    We demonstrate here that for a given mixed multi-qubit state if there are at least two observers for whom mutual Einstein-Podolsky-Rosen steering is possible, i.e. each observer is able to steer the other qubits into two different pure states by spontaneous collapses due to von Neumann type measurements on his/her qubit, then nonexistence of local realistic models is fully equivalent to quantum entanglement (this is not so without this condition). This result leads to an enhanced version of Gisin's theorem (originally: all pure entangled states violate local realism). Local realism is violated by all mixed states with the above steering property. The new class of states allows one e.g. to perform three party secret sharing with just pairs of entangled qubits, instead of three qubit entanglements (which are currently available with low fidelity). This significantly increases the feasibility of having high performance versions of such protocols. Finally, we discuss some possible applications.

  16. Overcoming the barrier of narrative adherence in conflicts through awareness of the psychological bias of naïve realism.

    PubMed

    Nasie, Meytal; Bar-Tal, Daniel; Pliskin, Ruthie; Nahhas, Eman; Halperin, Eran

    2014-11-01

    One significant socio-psychological barrier for peaceful resolution of conflicts is each party's adherence to its own collective narrative. We hypothesized that raising awareness to the psychological bias of naïve realism and its identification in oneself would provide a path to overcoming this barrier, thus increasing openness to the adversary's narrative. We conducted three experimental studies in the context of the Israeli-Palestinian conflict. Studies 1 and 2, conducted among Jewish Israelis and Palestinian Israelis, respectively, revealed that participants with hawkish political ideology reported greater openness to the adversary's narrative when they were made aware of naïve realism bias. Study 3 revealed that hawkish participants at the baseline adhered to the ingroup narrative and resisted the adversary's narrative more than dovish participants. They were also more able to identify the bias in themselves upon learning about it. This identification may explain why the manipulation led to bias correction only among hawkish participants.

  17. Denting the Hub, or Strengthening the Spokes? A Neoclassical Realism Analysis of New Security Trends in the Pacific

    DTIC Science & Technology

    2009-06-01

    The model proposed in this thesis resolves these limitations by identifying broadly applicable intervening variables. It does so by categorizing ...and robust manner to a variety of policy cases . Analysis by Neoclassical Realism and the intervening variable model permit an evaluation of the JADSC...The model proposed in this thesis resolves these limitations by identifying broadly applicable intervening variables. It does so by categorizing

  18. The Spin-S Einstein - Podolsky - Rosen Experiment and the Recovery of Local Realism in the Classical Limit.

    NASA Astrophysics Data System (ADS)

    Garg, Anupam Kumar

    This thesis consists of a study of the general spin Einstein-Podolsky-Rosen experiment, with a view to seeing how classical behavior is recovered in the infinite -spin limit. In Bohm's version of the experiment, two spin -s particles fly apart in the singlet state. Quantum theory predicts that if the spin of one particle is measured to be m along a direction a, the other will necessarily have a sping of -m along a. Since the spins of the two far apart particles can be measured in an infinitesimal time interval, the requirement of locality suggests that the particles' spins are predetermined along all directions, in defiance of quantum theoretic precepts. It was shown by Bell and by Clauser and Horne that an alternative point of view called local realism which attempts to explain the spin correlations by introducing hidden variables mut be incompatible with the quantitative predictions of quantum theory for spin- 1/2. Chapters II and III of this thesis contain extensions of their arguments to arbitrary spin. It is found that no matter how large the spin gets, quantum mechanics and local realism do not become more compatible, and classical mechanics does not emerge as a smooth infinite-spin limit. Chapter IV gives a general procedure (with several examples) for deciding whether or not a given set of joint distributions for the spins of the two particles is compatible with local realism. In Chapter V it is argued that local realism can emerge in the infinite-spin limit only if limitations in detector resolution (quite unrelated to those imposed by the uncertainty principle) are explicitly included. Some questions stemming from this point of view are answered for spin- 1/2, and a specific model for including detector error is studied for higher spin.

  19. Display signaling in augmented reality: effects of cue reliability and image realism on attention allocation and trust calibration.

    PubMed

    Yeh, M; Wickens, C D

    2001-01-01

    This experiment seeks to examine the relationships among three advanced technology features (presentation of target cuing, reliability of target cuing, and level of image reality and the attention and trust given to that information). The participants were 16 military personnel who piloted an unmanned air vehicle and searched for targets camouflaged in terrain, which was presented at two levels of image realism. Cuing was available for some targets, and the reliability of this information was manipulated at two levels (100% and 75%). The results showed that the presence of cuing aided target detection for expected targets but drew attention away from the presence of unexpected targets. Cuing benefits and attentional tunneling were both reduced when cuing became less reliable. Increasing image realism was compelling but increased reliance on the cuing information when those data were reliable. Potential applications include a cost-benefit analysis of how trust modulates attention in the use of automated target recognition systems and the extent to which increased realism may influence this trust.

  20. Assignment of the Stereochemistry and Anomeric Configuration of Sugars within Oligosaccharides Via Overlapping Disaccharide Ladders Using MSn

    NASA Astrophysics Data System (ADS)

    Konda, Chiharu; Londry, Frank A.; Bendiak, Brad; Xia, Yu

    2014-08-01

    A systematic approach is described that can pinpoint the stereo-structures (sugar identity, anomeric configuration, and location) of individual sugar units within linear oligosaccharides. Using a highly modified mass spectrometer, dissociation of linear oligosaccharides in the gas phase was optimized along multiple-stage tandem dissociation pathways (MSn, n = 4 or 5). The instrument was a hybrid triple quadrupole/linear ion trap mass spectrometer capable of high-efficiency bidirectional ion transfer between quadrupole arrays. Different types of collision-induced dissociation (CID), either on-resonance ion trap or beam-type CID could be utilized at any given stage of dissociation, enabling either glycosidic bond cleavages or cross-ring cleavages to be maximized when wanted. The approach first involves optimizing the isolation of disaccharide units as an ordered set of overlapping substructures via glycosidic bond cleavages during early stages of MSn, with explicit intent to minimize cross-ring cleavages. Subsequently, cross-ring cleavages were optimized for individual disaccharides to yield key diagnostic product ions ( m/ z 221). Finally, fingerprint patterns that establish stereochemistry and anomeric configuration were obtained from the diagnostic ions via CID. Model linear oligosaccharides were derivatized at the reducing end, allowing overlapping ladders of disaccharides to be isolated from MSn. High confidence stereo-structural determination was achieved by matching MSn CID of the diagnostic ions to synthetic standards via a spectral matching algorithm. Using this MSn ( n = 4 or 5) approach, the stereo-structures, anomeric configurations, and locations of three individual sugar units within two pentasaccharides were successfully determined.

  1. Crystal Structure of Aspirin-Acetylated Human Cyclooxygenase-2: Insight into the Formation of Products with Reversed Stereochemistry.

    PubMed

    Lucido, Michael J; Orlando, Benjamin J; Vecchio, Alex J; Malkowski, Michael G

    2016-03-01

    Aspirin and other nonsteroidal anti-inflammatory drugs target the cyclooxygenase enzymes (COX-1 and COX-2) to block the formation of prostaglandins. Aspirin is unique in that it covalently modifies each enzyme by acetylating Ser-530 within the cyclooxygenase active site. Acetylation of COX-1 leads to complete loss of activity, while acetylation of COX-2 results in the generation of the monooxygenated product 15(R)-hydroxyeicosatetraenoic acid (15R-HETE). Ser-530 has also been shown to influence the stereochemistry for the addition of oxygen to the prostaglandin product. We determined the crystal structures of S530T murine (mu) COX-2, aspirin-acetylated human (hu) COX-2, and huCOX-2 in complex with salicylate to 1.9, 2.0, and 2.4 Å, respectively. The structures reveal that (1) the acetylated Ser-530 completely blocks access to the hydrophobic groove, (2) the observed binding pose of salicylate is reflective of the enzyme-inhibitor complex prior to acetylation, and (3) the observed Thr-530 rotamer in the S530T muCOX-2 crystal structure does not impede access to the hydrophobic groove. On the basis of these structural observations, along with functional analysis of the S530T/G533V double mutant, we propose a working hypothesis for the generation of 15R-HETE by aspirin-acetylated COX-2. We also observe differential acetylation of COX-2 purified in various detergent systems and nanodiscs, indicating that detergent and lipid binding within the membrane-binding domain of the enzyme alters the rate of the acetylation reaction in vitro.

  2. Stereochemistry and Mechanism of Undecylprodigiosin Oxidative Carbocyclization to Streptorubin B by the Rieske Oxygenase RedG.

    PubMed

    Withall, David M; Haynes, Stuart W; Challis, Gregory L

    2015-06-24

    The prodiginines are a group of specialized metabolites that share a 4-methoxypyrrolyldipyrromethene core structure. Streptorubin B is a structurally remarkable member of the prodiginine group produced by Streptomyces coelicolor A3(2) and other actinobacteria. It is biosynthesized from undecylprodigiosin by an oxidative carbocyclization catalyzed by the Rieske oxygenase-like enzyme RedG. Undecylprodigiosin derives from the RedH-catalyzed condensation of 2-undecylpyrrole and 4-methoxy-2, 2'-bipyrrole-5-carboxaldehyde (MBC). To probe the mechanism of the RedG-catalyzed reaction, we synthesized 2-(5-pentoxypentyl)-pyrrole, an analogue of 2-undecylpyrrole with an oxygen atom next to the site of C-C bond formation, and fed it, along with synthetic MBC, to Streptomyces albus expressing redH and redG. This resulted in the production of the 6'-oxa analogue of undecylprodigiosin. In addition, a small amount of a derivative of this analogue lacking the n-pentyl group was produced, consistent with a RedG catalytic mechanism involving hydrogen abstraction from the alkyl chain of undecylprodigiosin prior to pyrrole functionalization. To investigate the stereochemistry of the RedG-catalyzed oxidative carbocyclization, [7'-(2)H](7'R)-2-undecylpyrrole and [7'-(2)H](7'S)-2-undecylpyrrole were synthesized and fed separately, along with MBC, to S. albus expressing redH and redG. Analysis of the extent of deuterium incorporation into the streptorubin B produced in these experiments showed that the pro-R hydrogen atom is abstracted from C-7' of undecylprodigiosin and that the reaction proceeds with inversion of configuration at C-7'. This contrasts sharply with oxidative heterocyclization reactions catalyzed by other nonheme iron-dependent oxygenase-like enzymes, such as isopenicillin N synthase and clavaminate synthase, which proceed with retention of configuration at the carbon center undergoing functionalization.

  3. THE CRYSTAL STRUCTURE OF ASPIRIN ACETYLATED HUMAN CYCLOOXYGENASE-2: INSIGHT INTO THE FORMATION OF PRODUCTS WITH REVERSED STEREOCHEMISTRY

    PubMed Central

    Lucido, Michael J.; Orlando, Benjamin J.; Vecchio, Alex J.; Malkowski, Michael G.

    2016-01-01

    Aspirin and other nonsterroidal anti-inflammatory drugs target the Cyclooxygenase enzymes (COX-1 and COX-2) to block the formation of prostaglandins. Aspirin is unique in that it covalently modifies each enzyme by acetylating Ser-530 within the cyclooxygenase active site. Acetylation of COX-1 leads to complete loss of activity, while acetylation of COX-2 results in the generation of the mono-oxygenated product 15(R)-hydroxyeicosatetraenoic acid (15R-HETE). Ser-530 has also been shown to influence the stereochemistry for oxygen addition into the prostaglandin product. We determined the crystal structures of S530T murine (mu) COX-2, aspirin-acetylated human (hu) COX-2, and huCOX-2 in complex with salicylate to 1.9Å, 2.0Å, and 2.4Å, respectively. The structures reveal that: 1) the acetylated Ser-530 completely blocks access to the hydrophobic groove; 2) the observed binding pose of salicylate is reflective of the enzyme-inhibitor complex prior to acetylation; and 3) the observed Thr-530 rotamer in the S530T muCOX-2 crystal structure does not impede access to the hydrophobic groove. Based on these structural observations, along with functional analysis of the S530T/G533V double mutant, we propose a working hypothesis for the generation of 15R-HETE by aspirin-acetylated COX-2. We also observe differential acetylation of COX-2 purified in various detergent systems and nanodiscs, indicating that detergent and lipid binding within the membrane-binding domain of the enzyme alters the rate of the acetylation reaction in vitro. PMID:26859324

  4. Biosynthesis of monoterpenes. Stereochemistry of the enzymatic cyclizations of geranyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene

    SciTech Connect

    Croteau, R.; Satterwhite, D.M.; Wheeler, C.J.; Felton, N.M.

    1989-02-05

    The conversion of geranyl pyrophosphate to (+)-alpha-pinene and to (-)-beta-pinene is considered to proceed by the initial isomerization of the substrate to (-)-(3R)- and to (+)-(3S)-linalyl pyrophosphate, respectively, and the subsequent cyclization of the anti, endo-conformer of these bound intermediates by mirror-image sequences which should result in the net retention of configuration at C1 of the geranyl precursor. Incubation of (1R)-(2-14C,1-3H)- and (1S)-(2-14C,1-3H)geranyl pyrophosphate with (+)-pinene cyclase and with (-)-pinene cyclase from common sage (Salvia officinalis) gave labeled (+)-alpha- and (-)-beta-pinene of unchanged 3H/14C ratio in all cases, and the (+)- and (-)-olefins were stereoselectively converted to (+)- and (-)-borneol, respectively, which were oxidized to the corresponding (+)- and (-)-isomers of camphor, again without change in isotope ratio. The location of the tritium was determined in each case by stereoselective, base-catalyzed exchange of the exo-alpha-hydrogens of these derived ketones. The results indicated that the configuration at C1 of the substrate was retained in the enzymatic transformations to the (+)- and (-)-pinenes, which is entirely consistent with the syn-isomerization of geranyl pyrophosphate to linalyl pyrophosphate, transoid to cisoid rotation, and anti, endo-cyclization of the latter. The absolute stereochemical elements of the antipodal reaction sequences were confirmed by the selective enzymatic conversions of (3R)- and (3S)-1Z-(1-3H)linalyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene, respectively, and by the location of the tritium in the derived camphors as before. The summation of the results fully defines the overall stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to the antipodal pinenes.

  5. New realism in north Korean propaganda: The death of Pak Chong-ch`ol. Final report

    SciTech Connect

    Shaw, W.

    1987-04-01

    North Korea`s Voice of National Salvation (VNS) broadcasts to South Korea in January and February gave considerable attention to the 13 January 1987 death under police torture of Seoul National University student Pak Chong-ch`ol. VNS commentary emphasized the routine nature of police torture in South Korea and sharply criticized the South Korean Government for blocking attendance at memorial services on 7 February and 3 March. Many VNS comments on the Pak case closely paralleled reactions of the South Korean press and parliamentary opposition, demonstrating close North Korean attention to opinion trends in the South. In a new mood of realism, P`yongyang also used the Pak case to urge South Korean radical students to drop their `avant-gardism`, including excessively leftist slogans and violent tactics that alienate the general populace. P` yongyang clearly wants students to take advantage of issues that have wide public appeal and to broaden resistance to the Chon Tu-hwan Government to include social groups beyond the student population. In P`yongyang`s view, such issues include the Pak case and the signature campaign for constitutional revision in early 1986. If South Korea`s radical students take P`yonyyang`s advice, and if the Republic of Korea Government fails to curb and punish abuses like the Pak killing, this shift in tactics could have significant influence during the coming spring demonstration season.

  6. A strict experimental test of macroscopic realism in a superconducting flux qubit

    PubMed Central

    Knee, George C.; Kakuyanagi, Kosuke; Yeh, Mao-Chuang; Matsuzaki, Yuichiro; Toida, Hiraku; Yamaguchi, Hiroshi; Saito, Shiro; Leggett, Anthony J.; Munro, William J.

    2016-01-01

    Macroscopic realism is the name for a class of modifications to quantum theory that allow macroscopic objects to be described in a measurement-independent manner, while largely preserving a fully quantum mechanical description of the microscopic world. Objective collapse theories are examples which aim to solve the quantum measurement problem through modified dynamical laws. Whether such theories describe nature, however, is not known. Here we describe and implement an experimental protocol capable of constraining theories of this class, that is more noise tolerant and conceptually transparent than the original Leggett–Garg test. We implement the protocol in a superconducting flux qubit, and rule out (by ∼84 s.d.) those theories which would deny coherent superpositions of 170 nA currents over a ∼10 ns timescale. Further, we address the ‘clumsiness loophole' by determining classical disturbance with control experiments. Our results constitute strong evidence for the superposition of states of nontrivial macroscopic distinctness. PMID:27811844

  7. Pattern cladistics and the 'realism-antirealism debate' in the philosophy of biology.

    PubMed

    Vergara-Silva, Francisco

    2009-06-01

    Despite the amount of work that has been produced on the subject over the years, the 'transformation of cladistics' is still a misunderstood episode in the history of comparative biology. Here, I analyze two outstanding, highly contrasting historiographic accounts on the matter, under the perspective of an influential dichotomy in the philosophy of science: the opposition between Scientific Realism and Empiricism. Placing special emphasis on the notion of 'causal grounding' of morphological characters (sensu Olivier Rieppel) in modern developmental biology's (mechanistic) theories, I arrive at the conclusion that a 'new transformation of cladistics' is philosophically plausible. This 'reformed' understanding of 'pattern cladistics' entails retaining the interpretation of cladograms as 'schemes of synapomorphies', but in association to construing cladogram nodes as 'developmental-genetic taxic homologies', instead of 'standard Darwinian ancestors'. The reinterpretation of pattern cladistics presented here additionally proposes to take Bas Van Fraassen's 'constructive empiricism' as a philosophical stance that could properly support such analysis of developmental-genetic data for systematic purposes. The latter suggestion is justified through a reappraisal of previous ideas developed by prominent pattern cladists (mainly, Colin Patterson), which concerned a scientifically efficient 'observable/non-observable distinction' linked to the conceptual pair 'ontogeny and phylogeny'. Finally, I argue that a robust articulation of Antirealist alternatives in systematics may provide a rational basis for its disciplinary separation from evolutionary biology, as well as for a critical reconsideration of the proper role of certain Scientific Realist positions, currently popular in comparative biology.

  8. Perceptions of risk in motorcyclists: unrealistic optimism, relative realism and predictions of behaviour.

    PubMed

    Rutter, D R; Quine, L; Albery, I P

    1998-11-01

    In the first phase of a prospective investigation, a national sample of motorcyclists completed a postal questionnaire about their perceptions of risk, their behaviour on the roads and their history of accidents and spills. In the second phase a year later, they reported on their accident history and behaviour over the preceding 12 months. A total of 723 respondents completed both questionnaires. Four sets of findings are reported. First, the group as a whole showed unrealistic optimism: on average, respondents believed themselves to be less at risk than other motorcyclists of an accident needing hospital treatment in the next year. Second, optimism was tempered by 'relative realism', in that respondents who were young and inexperienced saw themselves as more at risk than other motorcyclists, as did riders who reported risky behaviours on the road. Third, there was some evidence of debiasing by personal history, in that having a friend or a relative who had been killed or injured on the roads was associated with perceptions of absolute risk of injury or death--though there were no effects on comparative risk and no effects on any of the judgments of a history of accidents of one's own. Finally, there was good evidence that perceptions of risk predicted subsequent behaviour, though generally in the direction not of precaution adoption but of precaution abandonment: the greater the perceived risk at time 1, the more frequent the risky behaviour at time 2. The implications of the findings are discussed, and possible interpretations are suggested.

  9. Feeling and Time: The Phenomenology of Mood Disorders, Depressive Realism, and Existential Psychotherapy

    PubMed Central

    Ghaemi, S. Nassir

    2007-01-01

    Phenomenological research suggests that pure manic and depressive states are less common than mixtures of the two and that the two poles of mood are characterized by opposite ways of experiencing time. In mania, the subjective experience of time is sped up and in depression it is slowed down, perhaps reflecting differences in circadian pathophysiology. The two classic mood states are also quite different in their effect on subjective awareness: manic patients lack insight into their excitation, while depressed patients are quite insightful into their unhappiness. Consequently, insight plays a major role in overdiagnosis of unipolar depression and misdiagnosis of bipolar disorder. The phenomenology of depression also is relevant to types of psychotherapies used to treat it. The depressive realism (DR) model, in contrast to the cognitive distortion model, appears to better apply to many persons with mild to moderate depressive syndromes. I suggest that existential psychotherapy is the necessary corollary of the DR model in those cases. Further, some depressive morbidities may in fact prove, after phenomenological study, to involve other mental states instead of depression. The chronic subsyndromal depression that is often the long-term consequence of treated bipolar disorder may in fact represent existential despair, rather than depression proper, again suggesting intervention with existential psychotherapeutic methods. PMID:17122410

  10. Statistical strength of experiments to reject local realism with photon pairs and inefficient detectors

    SciTech Connect

    Zhang Yanbao; Knill, Emanuel; Glancy, Scott

    2010-03-15

    Because of the fundamental importance of Bell's theorem, a loophole-free demonstration of a violation of local realism (LR) is highly desirable. Here, we study violations of LR involving photon pairs. We quantify the experimental evidence against LR by using measures of statistical strength related to the Kullback-Leibler (KL) divergence, as suggested by van Dam et al.[W. van Dam, R. D. Gill, and P. D. Grunwald, IEEE Trans. Inf. Theory. 51, 2812 (2005)]. Specifically, we analyze a test of LR with entangled states created from two independent polarized photons passing through a polarizing beam splitter. We numerically study the detection efficiency required to achieve a specified statistical strength for the rejection of LR depending on whether photon counters or detectors are used. Based on our results, we find that a test of LR free of the detection loophole requires photon counters with efficiencies of at least 89.71%, or photon detectors with efficiencies of at least 91.11%. For comparison, we also perform this analysis with ideal unbalanced Bell states, which are known to allow rejection of LR with detector efficiencies above 2/3.

  11. Testing quantum mechanics against macroscopic realism using the output of {chi}{sup (2)} nonlinearity

    SciTech Connect

    Podoshvedov, Sergey A.; Kim, Jaewan

    2006-09-15

    We suggest an all-optical scheme to generate entangled superposition of a single photon with macroscopic entangled states for testing macroscopic realism. The scheme consists of source of single photons, a Mach-Zehnder interferometer in routes of which a system of coupled-down converters with type-I phase matching is inserted, and a beam splitter for the other auxiliary modes of the scheme. We use quantization of the pumping modes, depletion of the coherent states passing through the system, and interference effect in the pumping modes in the process of erasing which-path information of the single-photon on exit from the Mach-Zehnder interferometer. We show the macroscopic fields of the output superposition are distinguishable states. This scheme generates macroscopic entangled state that violates Bell's inequality. Moreover, the detailed analysis concerning change of amplitudes of entangled superposition by means of repeating this process many times is accomplished. We show our scheme works without photon number resolving detection and it is robust to detector inefficiency.

  12. Biomarkers: are realism and control mutually exclusive in integrated pollution assessment?

    PubMed

    Wilson, J G; McHugh, B; Giltrap, M

    2014-12-01

    The conventional view of pollution monitoring is that any choice is a trade-off between realism and precision, as the control over confounding variables decreases with the increasing degree of organization of the test system. Dublin Bay is subject to considerable anthropogenic pressures and there have been many attempts to quantify the status of the system at organizational levels from DNA strand breaks (Comet) to the system itself (Ecological Network analysis, ENA). Using Dublin Bay as an example, the data show there was considerable variability at all levels of organization. At intracellular level, Lysosome Membrane Stability (LMS, assessed by Neutral Red Retention, NRR) varied almost 4-fold with season and individual condition, while the community level AZTI Marine biotic Index (AMBI) had a similar range within a single, supposedly homogeneous, site. Overall, there was no evidence that biomarkers of the lower levels of organisation reduced the variability of the measure, despite the extra control over influencing variables, nor was there any evidence that variability was additive at higher levels of organisation. This poses problems for management, especially given the fixed limits of Ecological Quality Standards (EQSs). Clearly while the integrated approach to pollution monitoring does offer the potential to link effects across the organizational range, it should also be possible to improve their capability by widening the database for reference values, particularly at the higher level of organization, and by process models, including the confounding variables found in the field, for those at lower level.

  13. [Painting realism and medicine: the two surgical clinics of Thomas Eakins].

    PubMed

    Cabello, Felipe

    2015-06-01

    Realism is a painting style that began with Millet and Courbet in politically convulsed France in the middle of the nineteenth century. In the second half of that century, the pragmatic and democratic tradition of the United States fostered the careers of many realist painters, including that of Thomas Eakins. Eakins, trained in France, developed his career completely associated with Philadelphia at a time when this city was in the vanguard of American emerging industry, culture and medicine. Eakins "The clinic of Dr. Gross" and the "The clinic of Dr. Agnew" are icons of these developments and symbolize a perfect union of art and medicine. Both paintings permit the viewer to appreciate the artist's mastery, originality and Americanism while simultaneously tracking the progress of surgery as evidenced by the introduction of asepsis, anesthesia and nursing. Eakins mastery is revealed by its use of some European Old Masters approaches to portray medical professionals undertaking their daily duties in their work environments with critical and unadorned vision. This combination of vision and skills led Eakins to create a highly original yet analytical art. Unfortunately, his representations were far ahead of his time and resulted in under appreciation of his paintings and a censorious reaction to their content. His contemporaries rejection of Eakins work negatively affected his career as a painter, as a teacher and even his private life. This judgment was overturned in subsequent years and by the twentieth century Eakins was recognized as an American master without parallel.

  14. Toward a limited realism for psychiatric nosology based on the coherence theory of truth.

    PubMed

    Kendler, K S

    2015-04-01

    A fundamental debate in the philosophy of science is whether our central concepts are true or only useful instruments to help predict and manipulate the world. The first position is termed 'realism' and the second 'instrumentalism'. Strong support for the instrumentalist position comes from the 'pessimistic induction' (PI) argument. Given that many key scientific concepts once considered true (e.g., humors, ether, epicycles, phlogiston) are now considered false, how, the argument goes, can we assert that our current concepts are true? The PI argument applies strongly to psychiatric diagnoses. Given our long history of abandoned diagnoses, arguments that we have finally 'gotten it right' and developed definitive psychiatric categories that correspond to observer-independent reality are difficult to defend. For our current diagnostic categories, we should settle for a less ambitious vision of truth. For this, the coherence theory, which postulates that something is true when it fits well with the other things we confidently know about the world, can serve us well. Using the coherence theory, a diagnosis is real to the extent that it is well integrated into our accumulating scientific data base. Furthermore, the coherence theory establishes a framework for us to evaluate our diagnostic categories and can provide a set of criteria, closely related to our concept of validators, for deciding when they are getting better. Finally, we need be much less skeptical about the truth status of the aggregate concept of psychiatric illness than we are regarding the specific categories in our current nosology.

  15. Reality Without Realism: On the Ontological and Epistemological Architecture of Quantum Mechanics

    NASA Astrophysics Data System (ADS)

    Plotnitsky, Arkady; Khrennikov, Andrei

    2015-10-01

    First, this article considers the nature of quantum reality (the reality responsible for quantum phenomena) and the concept of realism (our ability to represent this reality) in quantum theory, in conjunction with the roles of locality, causality, and probability and statistics there. Second, it offers two interpretations of quantum mechanics, developed by the authors of this article, the second of which is also a different (from quantum mechanics) theory of quantum phenomena. Both of these interpretations are statistical. The first interpretation, by A. Plotnitsky, "the statistical Copenhagen interpretation," is nonrealist, insofar as the description or even conception of the nature of quantum objects and processes is precluded. The second, by A. Khrennikov, is ultimately realist, because it assumes that the quantum-mechanical level of reality is underlain by a deeper level of reality, described, in a realist fashion, by a model, based in the pre-quantum classical statistical field theory, the predictions of which reproduce those of quantum mechanics. Moreover, because the continuous fields considered in this model are transformed into discrete clicks of detectors, experimental outcomes in this model depend on the context of measurement in accordance with N. Bohr's interpretation and the statistical Copenhagen interpretation, which coincides with N. Bohr's interpretation in this regard.

  16. Contextualism adds realism: nursing students' perceptions of and performance in numeracy skills tests.

    PubMed

    Ramjan, Lucie M

    2011-11-01

    This project investigated nursing students' perceptions of and performance in a de-contextualised diagnostic maths paper (i.e. questions only) and a contextualised diagnostic maths paper (i.e. visual pictures along with questions). Sampling was purposive, the criteria being that participants would be from the population of student nurses (n=700) in their second year, of a three-year Bachelor of Nursing course, undertaking a Unit 'Medical-Surgical Nursing 1' (MSN1) at one of four campuses across the University of Western Sydney (UWS), NSW, Australia. The numerical test scores for both papers were analysed with the assistance of SPSS software and a Professional Development Officer. The survey data were analysed manually and thematically by the researcher. There was a substantive improvement in scores from Test 1 (de-contextualised) to Test 2 (contextualised). It is uncertain whether the change occurred because Test 2 is a genuinely better presentation than Test 1 or just a practice effect. Nevertheless, the contextualised paper was preferred by the majority of students (80%). Students preferred the visual images and revealed that it led to a "deeper learning" of numeracy skills, reduced stress and anxiety levels and simulated 'the real life' clinical setting, thus adding "an element of realism" to the situation.

  17. Realism without truth: a review of Giere's science without laws and scientific perspectivism.

    PubMed

    Hackenberg, Timothy D

    2009-05-01

    An increasingly popular view among philosophers of science is that of science as action-as the collective activity of scientists working in socially-coordinated communities. Scientists are seen not as dispassionate pursuers of Truth, but as active participants in a social enterprise, and science is viewed on a continuum with other human activities. When taken to an extreme, the science-as-social-process view can be taken to imply that science is no different from any other human activity, and therefore can make no privileged claims about its knowledge of the world. Such extreme views are normally contrasted with equally extreme views of classical science, as uncovering Universal Truth. In Science Without Laws and Scientific Perspectivism, Giere outlines an approach to understanding science that finds a middle ground between these extremes. He acknowledges that science occurs in a social and historical context, and that scientific models are constructions designed and created to serve human ends. At the same time, however, scientific models correspond to parts of the world in ways that can legitimately be termed objective. Giere's position, perspectival realism, shares important common ground with Skinner's writings on science, some of which are explored in this review. Perhaps most fundamentally, Giere shares with Skinner the view that science itself is amenable to scientific inquiry: scientific principles can and should be brought to bear on the process of science. The two approaches offer different but complementary perspectives on the nature of science, both of which are needed in a comprehensive understanding of science.

  18. Synthesis of precursors to and spectroscopic characterization of highly unsaturated carbenes and diradicals and development and implementation of a web-based stereochemistry tutorial

    NASA Astrophysics Data System (ADS)

    Burrmann, Nicola Jean

    A variety of substituted diynols, diynals, and diynones have been prepared en route to the synthesis of precursors to dialkynyl carbenes (R1--C≡C--C--C≡C--R 2). In light of the unique reactivity associated with these simple systems, several strategies were required to assemble the carbon backbones (Chapter I). Tosylhydrazone and trisylhydrazone precursors to 2-diazo-3-pentyne ( 1), 2-diazo-3-butyne (2), and Idiazo-2-butyne ( 3) were synthesized and then converted into their respective diazo compounds. Various attempts to study these diazo compounds using matrix isolation IR and EPR spectroscopy were made and proved to be unsuccessful. Computations were done to characterize the C5H6 potential energy surface, as well as to determine the IR vibrational frequencies of the isomers on this surface (Chapter 2). A web-based Stereochemistry Tutorial that details the core definitions and structural representations relevant to organic stereochemistry was designed and implemented into several introductory-level organic chemistry classes. This tutorial also allows for students to select their preferred structural representation and method for making stereochemical comparisons between molecules. The tutorial was evaluated, either qualitatively, quantitatively, or both, by students in three different introductory organic chemistry courses at the University of Wisconsin---Madison. The data show that students did use a variety of different methods for making stereochemical comparisons between molecules, and that prior exposure to lectures on stereochemistry by the course professor strongly influenced these choices. Furthermore, the level of improvement in stereochemical knowledge as a result of using only the tutorial was comparable to, or higher than, that achieved by students who were only exposed to lectures by the course professor, regardless of the method chosen for making stereochemical comparisons between molecules (Chapter 3)

  19. N-benzoyl-1,5-benzothiazepine and its S-oxide as vasopressin receptor ligands: insight into the active stereochemistry around the seven-membered ring.

    PubMed

    Yoneda, Tetsuya; Tabata, Hidetsugu; Tasaka, Tomohiko; Oshitari, Tetsuta; Takahashi, Hideyo; Natsugari, Hideaki

    2015-04-09

    The stereochemistry of N-benzoyl-1,5-benzothiazepine and its S-oxide derivatives as vasopressin receptor ligands was examined in detail by freezing the conformation with a methyl group at the C6 or C9 of 1,5-benzothiazepine. It was revealed that the active forms recognized by the receptors are (cis,aS) for 1,5-benzothiazepine (5-7)-II and (cis,1S,aS) (syn) for its S-oxide (8-10)-II. The C9-methyl derivative of 1,5-benzothiazepine S-oxide (10-II) was designed and synthesized, achieving the putative active syn-isomer.

  20. Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ⁵-oxaphosphetanes.

    PubMed

    Kolodiazhna, Anastasy O; Kolodiazhnyi, Oleg I

    2016-10-17

    Results of research into four-membered 2-halo-1,2λ⁵-oxaphosphetane phosphorus(V)-heterocycles are presented. The preparation of 2-halo-1,2λ⁵-oxaphosphetanes by reaction of P-haloylides with carbonyl compounds is described. The mechanism of asynchronous [2+2]-сycloaddition of ylides to aldehydes was proposed on the base of low-temperature NMR investigations. 2-Halo-1,2λ⁵-oxaphosphetanes were isolated as individual compounds and their structures were confirmed by ¹Н-, (13)C-, (19)F- and (31)Р-NMR spectra. These compounds are convenient reagents for preparing of various organic and organophosphorus compounds hardly available by other methods. Chemical and physical properties of the 2-halo-1,2λ⁵-oxaphosphetanes are reviewed. The 2-chloro-1,2λ⁵-oxaphosphetanes, rearrange with formation of 2-chloroalkyl-phosphonates or convert into trans-phosphorylated alkenes depending on the substituents at the α-carbon atom. Prospective synthetic applications of 2-halo-1,2λ⁵-oxaphosphetanes are analyzed. The 2-halo-1,2λ⁵-oxaphosphetanes may be easily converted to various alkenylphosphonates: allyl- or vinylphosphonates, phosphorus ketenes, thioketenes, ketenimines.

  1. Improving the realism of hydrologic model functioning through multivariate parameter estimation

    NASA Astrophysics Data System (ADS)

    Rakovec, O.; Kumar, R.; Attinger, S.; Samaniego, L.

    2016-10-01

    Increased availability and quality of near real-time observations provide the opportunity to improve understanding of predictive skills of hydrologic models. Recent studies have shown the limited capability of river discharge data alone to adequately constrain different components of distributed model parameterizations. In this study, the GRACE satellite-based total water storage (TWS) anomaly is used to complement the discharge data with the aim to improve the fidelity of mesoscale hydrologic model (mHM) through multivariate parameter estimation. The study is conducted on 83 European basins covering a wide range of hydroclimatic regimes. The model parameterization complemented with the TWS anomalies leads to statistically significant improvements in (1) discharge simulations during low-flow period, and (2) evapotranspiration estimates which are evaluated against independent data (FLUXNET). Overall, there is no significant deterioration in model performance for the discharge simulations when complemented by information from the TWS anomalies. However, considerable changes in the partitioning of precipitation into runoff components are noticed by in-/exclusion of TWS during the parameter estimation. Introducing monthly averaged TWS data only improves the dynamics of streamflow on monthly or longer time scales, which mostly addresses the dynamical behavior of the base flow reservoir. A cross-evaluation test carried out to assess the transferability of the calibrated parameters to other locations further confirms the benefit of complementary TWS data. In particular, the evapotranspiration estimates show more robust performance when TWS data are incorporated during the parameter estimation, in comparison with the benchmark model constrained against discharge only. This study highlights the value for incorporating multiple data sources during parameter estimation to improve the overall realism of hydrologic models and their applications over large domains.

  2. Cork suberin molecular structure: stereochemistry of the C18 epoxy and vic-diol ω-hydroxyacids and α,ω-diacids analyzed by NMR.

    PubMed

    Santos, Sara; Cabral, Vanessa; Graça, José

    2013-07-24

    Suberin is the biopolyester that protects the secondary tissues of plants against environmental variability and aggressions. Cork suberin is composed mostly of C18 ω-hydroxyacids and α,ω-diacids, 9,10-substituted with an unsaturation, an epoxide ring, or a vic-diol group. Although determinant for suberin macromolecular structure, the stereochemistry of these monomers is poorly studied, sometimes with contradictory results. An NMR technique was used here to assign the configuration of the 9,10-epoxy and 9,10-diol groups in C18 suberin acids, comparing the chemical shifts of diagnostic (1)H and (13)C signals with the ones of model compounds, before and after conversion of the vic-diol group into benzylidene acetal derivatives. The relative configuration was proved to be cis in the C18 9,10-epoxy and threo in the C18 9,10-diol suberin acids. These monomers were present in suberin probably as racemic mixtures, as shown by polarimetry. The revealed stereochemistry allows the suberin macromolecule to be built as an ordered array of midchain kinked C18 acids, reinforced by intramolecular hydrogen bonding.

  3. Correlations among experimental and theoretical NMR data to determine the absolute stereochemistry of darcyribeirine, a pentacyclic indole alkaloid isolated from Rauvolfia grandiflora

    NASA Astrophysics Data System (ADS)

    Cancelieri, Náuvia Maria; Ferreira, Thiago Resende; Vieira, Ivo José Curcino; Braz-Filho, Raimundo; Piló-Veloso, Dorila; Alcântara, Antônio Flávio de Carvalho

    2015-10-01

    Darcyribeirine (1) is a pentacyclic indole alkaloid isolated from Rauvolfia grandiflora. Stereochemistry of 1 was previously proposed based on 1D (coupling constant data) and 2D (NOESY correlations) NMR techniques, having been established a configuration 3R, 15S, and 20R (isomer 1a). Stereoisomers of 1 (i.e., 1a-1h) can be grouped into four sets of enantiomers. Carbon chemical shifts and hydrogen coupling constants were calculated using BLYP/6-31G* theory level for the eight isomers of 1. Calculated NMR data of 1a-1h were correlated with the corresponding experimental data of 1. The best correlations between theoretical and experimental carbon chemical shift data were obtained for the set of enantiomers 1e/1f to structures in the gaseous phase and considering solvent effects (using PCM and explicit models). Similar results were obtained when the same procedure was performed to correlations between theoretical and experimental coupling constant data. Finally, optical rotation calculations indicate 1e as its absolute stereochemistry. Orbital population analysis indicates that the hydrogen bonding between N-H of 1e and DMSO is due to contributions of its frontier unoccupied molecular orbitals, mainly LUMO+1, LUMO+2, and LUMO+3.

  4. Critical realism: a practical ontology to explain the complexities of smoking and tobacco control in different resource settings

    PubMed Central

    Oladele, Dunsi; Clark, Alexander M.; Richter, Solina; Laing, Lory

    2013-01-01

    Background This paper presents critical realism (CR) as an innovative system for research in tobacco prevention and control. CR argues that underlying mechanisms are considered and explored to ensure effective implementation of any program/policy or intervention. Any intervention or program/policy that is transposed from one country to another or one setting to another is complex. Methods The research was undertaken and analyzed through a critical ethnography lens using CR as a philosophical underpinning. The study relied upon the following components: original fieldwork in Nigeria including participant observation of smokers, in-depth interviews and focus groups with smokers, and in-depth interviews with health professionals working in the area of tobacco control in Nigeria. Results Findings from this small ethnographic study in Nigeria, suggest that Critical Realism holds promise for addressing underlying mechanism that links complex influences on smoking. Conclusion This paper argues that understanding the underlying mechanisms associated with smoking in different societies will enable a platform for effective implementation of tobacco control policies that work in various settings. PMID:23561029

  5. Emergence of realism: Enhanced visual artistry and high accuracy of visual numerosity representation after left prefrontal damage.

    PubMed

    Takahata, Keisuke; Saito, Fumie; Muramatsu, Taro; Yamada, Makiko; Shirahase, Joichiro; Tabuchi, Hajime; Suhara, Tetsuya; Mimura, Masaru; Kato, Motoichiro

    2014-05-01

    Over the last two decades, evidence of enhancement of drawing and painting skills due to focal prefrontal damage has accumulated. It is of special interest that most artworks created by such patients were highly realistic ones, but the mechanism underlying this phenomenon remains to be understood. Our hypothesis is that enhanced tendency of realism was associated with accuracy of visual numerosity representation, which has been shown to be mediated predominantly by right parietal functions. Here, we report a case of left prefrontal stroke, where the patient showed enhancement of artistic skills of realistic painting after the onset of brain damage. We investigated cognitive, functional and esthetic characteristics of the patient׳s visual artistry and visual numerosity representation. Neuropsychological tests revealed impaired executive function after the stroke. Despite that, the patient׳s visual artistry related to realism was rather promoted across the onset of brain damage as demonstrated by blind evaluation of the paintings by professional art reviewers. On visual numerical cognition tasks, the patient showed higher performance in comparison with age-matched healthy controls. These results paralleled increased perfusion in the right parietal cortex including the precuneus and intraparietal sulcus. Our data provide new insight into mechanisms underlying change in artistic style due to focal prefrontal lesion.

  6. Critical realism: a practical ontology to explain the complexities of smoking and tobacco control in different resource settings.

    PubMed

    Oladele, Dunsi; Clark, Alexander M; Richter, Solina; Laing, Lory

    2013-01-01

    Background This paper presents critical realism (CR) as an innovative system for research in tobacco prevention and control. CR argues that underlying mechanisms are considered and explored to ensure effective implementation of any program/policy or intervention. Any intervention or program/policy that is transposed from one country to another or one setting to another is complex. Methods The research was undertaken and analyzed through a critical ethnography lens using CR as a philosophical underpinning. The study relied upon the following components: original fieldwork in Nigeria including participant observation of smokers, in-depth interviews and focus groups with smokers, and in-depth interviews with health professionals working in the area of tobacco control in Nigeria. Results Findings from this small ethnographic study in Nigeria, suggest that Critical Realism holds promise for addressing underlying mechanism that links complex influences on smoking. Conclusion This paper argues that understanding the underlying mechanisms associated with smoking in different societies will enable a platform for effective implementation of tobacco control policies that work in various settings.

  7. From home range dynamics to population cycles: validation and realism of a common vole population model for pesticide risk assessment.

    PubMed

    Wang, Magnus

    2013-04-01

    Despite various attempts to establish population models as standard tools in pesticide risk assessment, population models still receive limited acceptance by risk assessors and authorities in Europe. A main criticism of risk assessors is that population models are often not, or not sufficiently, validated. Hence the realism of population-level risk assessments conducted with such models remains uncertain. We therefore developed an individual-based population model for the common vole, Microtus arvalis, and demonstrate how population models can be validated in great detail based on published data. The model is developed for application in pesticide risk assessment, therefore, the validation covers all areas of the biology of the common vole that are relevant for the analysis of potential effects and recovery after application of pesticides. Our results indicate that reproduction, survival, age structure, spatial behavior, and population dynamics reproduced from the model are comparable to field observations. Also interannual population cycles, which are frequently observed in field studies of small mammals, emerge from the population model. These cycles were shown to be caused by the home range behavior and dispersal. As observed previously in the field, population cycles in the model were also stronger for longer breeding season length. Our results show how validation can help to evaluate the realism of population models, and we discuss the importance of taking field methodology and resulting bias into account. Our results also demonstrate how population models can help to test or understand biological mechanisms in population ecology.

  8. Is This Real Life? Is This Just Fantasy?: Realism and Representations in Learning with Technology

    NASA Astrophysics Data System (ADS)

    Sauter, Megan Patrice

    Students often engage in hands-on activities during science learning; however, financial and practical constraints often limit the availability of these activities. Recent advances in technology have led to increases in the use of simulations and remote labs, which attempt to recreate hands-on science learning via computer. Remote labs and simulations are interesting from a cognitive perspective because they allow for different relations between representations and their referents. Remote labs are unique in that they provide a yoked representation, meaning that the representation of the lab on the computer screen is actually linked to that which it represents: a real scientific device. Simulations merely represent the lab and are not connected to any real scientific devices. However, the type of visual representations used in the lab may modify the effects of the lab technology. The purpose of this dissertation is to examine the relation between representation and technology and its effects of students' psychological experiences using online science labs. Undergraduates participated in two studies that investigated the relation between technology and representation. In the first study, participants performed either a remote lab or a simulation incorporating one of two visual representations, either a static image or a video of the equipment. Although participants in both lab conditions learned, participants in the remote lab condition had more authentic experiences. However, effects were moderated by the realism of the visual representation. Participants who saw a video were more invested and felt the experience was more authentic. In a second study, participants performed a remote lab and either saw the same video as in the first study, an animation, or the video and an animation. Most participants had an authentic experience because both representations evoked strong feelings of presence. However, participants who saw the video were more likely to believe the

  9. Realism and Perspectivism: a Reevaluation of Rival Theories of Spatial Vision.

    NASA Astrophysics Data System (ADS)

    Thro, E. Broydrick

    1990-01-01

    My study reevaluates two theories of human space perception, a trigonometric surveying theory I call perspectivism and a "scene recognition" theory I call realism. Realists believe that retinal image geometry can supply no unambiguous information about an object's size and distance--and that, as a result, viewers can locate objects in space only by making discretionary interpretations based on familiar experience of object types. Perspectivists, in contrast, think viewers can disambiguate object sizes/distances on the basis of retinal image information alone. More specifically, they believe the eye responds to perspective image geometry with an automatic trigonometric calculation that not only fixes the directions and shapes, but also roughly fixes the sizes and distances of scene elements in space. Today this surveyor theory has been largely superceded by the realist approach, because most vision scientists believe retinal image geometry is ambiguous about the scale of space. However, I show that there is a considerable body of neglected evidence, both past and present, tending to call this scale ambiguity claim into question. I maintain that this evidence against scale ambiguity could hardly be more important, if one considers its subversive implications for the scene recognition theory that is not only today's reigning approach to spatial vision, but also the foundation for computer scientists' efforts to create space-perceiving robots. If viewers were deemed to be capable of automatic surveying calculations, the discretionary scene recognition theory would lose its main justification. Clearly, it would be difficult for realists to maintain that we viewers rely on scene recognition for space perception in spite of our ability to survey. And in reality, as I show, the surveyor theory does a much better job of describing the everyday space we viewers actually see--a space featuring stable, unambiguous relationships among scene elements, and a single horizon and

  10. State-to-state dynamics of H+c-RH→H 2( v', j')+c-R reactions: the influence of reactant stereochemistry

    NASA Astrophysics Data System (ADS)

    Srivastava, Abneesh; Picconatto, Carl A.; Valentini, James J.

    2002-03-01

    Rotational state distributions for the H2 v '=0 product from the H+c-C 4H 8 and H+c-C 5H 10 abstraction reactions are reported for 1.6 eV collision energy. These results are compared to those previously obtained by us for the H+c-C 6H 12 reaction. The H 2( v'=0, j') rotational state distributions from the H+c-C 5H 10 and H+c-C 6H 12 reactions are identical, within experimental uncertainty. In contrast, the H+c-C 4H 8 reaction produces an H 2( v'=0, j') distribution that is much warmer. These results are interpreted through a model of the reaction dynamics that invokes the characteristic stereochemistry of the reactants.

  11. Structural Reassignment and Absolute Stereochemistry of Madurastatin C1 (MBJ-0034) and the Related Aziridine Siderophores: Madurastatins A1, B1, and MBJ-0035.

    PubMed

    Tyler, Andrew R; Mosaei, Hamed; Morton, Stephanie; Waddell, Paul G; Wills, Corinne; McFarlane, William; Gray, Joe; Goodfellow, Michael; Errington, Jeff; Allenby, Nick; Zenkin, Nikolay; Hall, Michael J

    2017-04-11

    The madurastatins are pentapeptide siderophores originally described as containing an unusual salicylate-capped N-terminal aziridine ring. Isolation of madurastatin C1 (1) (also designated MBJ-0034), from Actinomadura sp. DEM31376 (itself isolated from a deep sea sediment), prompted structural reevaluation of the madurastatin siderophores, in line with the recent work of Thorson and Shaaban. NMR spectroscopy in combination with partial synthesis allowed confirmation of the structure of madurastatin C1 (1) as containing an N-terminal 2-(2-hydroxyphenyl)oxazoline in place of the originally postulated aziridine, while absolute stereochemistry was determined via Harada's advanced Marfey's method. Therefore, this work further supports Thorson and Shaaban's proposed structural revision of the madurastatin class of siderophores (madurastatins A1 (2), B1 (3), C1 (1), and MBJ-0036 (4)) as N-terminal 2-(2-hydroxyphenyl)oxazolines.

  12. Role of the side chain stereochemistry in the α-glucosidase inhibitory activity of kotalanol, a potent natural α-glucosidase inhibitor. Part 2.

    PubMed

    Tanabe, Genzoh; Matsuoka, Kanjyun; Yoshinaga, Masahiro; Xie, Weijia; Tsutsui, Nozomi; A Amer, Mumen F; Nakamura, Shinya; Nakanishi, Isao; Wu, Xiaoming; Yoshikawa, Masayuki; Muraoka, Osamu

    2012-11-01

    To examine the role of the side chain of kotalanol (2), a potent natural α-glucosidase inhibitor isolated from Salacia reticulata, on inhibitory activity, four diastereomers (11a-11d) with reversed configuration (S) at the C-4' position in the side chain were synthesized and evaluated. Two of the four (11b and 11d) significantly lost their inhibitory activity against both maltase and sucrase, while the other two (11a and 11c) sustained the inhibitory activity to a considerable extent, showing distinct activity in response to the change of stereochemistry of the hydroxyls at the 5'and 6' positions. Different activities were rationalized with reference to in silico docking studies on these inhibitors with hNtMGAM. Against isomaltase, all four analogs showed potent inhibitory activity as well as 2, and 11b and 11d exhibited enzyme selectivity.

  13. Structural determination of molecular stereochemistry using VCD spectroscopy and a conformational code: absolute configuration and solution conformation of a chiral liquid pesticide, (R)-(+)-malathion.

    PubMed

    Izumi, Hiroshi; Ogata, Atsushi; Nafie, Laurence A; Dukor, Rina K

    2009-01-01

    The absolute configuration and solution conformation of (R)-(+)-malathion were determined by using vibrational circular dichroism spectroscopy and a fragment-conformational search with a recently published conformational code. The determination of molecular stereochemistry was carried out without a conformational search using molecular mechanics calculations. Density functional theory calculations of the fragments of (R)-malathion, ethyl propionate, (R)-ethyl 2-(methylthio)propanoate, (R)-diethyl 2-(methylthio)succinate, and O,O,S-trimethyl phosphorodithioate were carried out, and the principal conformational features of the fragments were profiled. This fragment-conformational search reduces the time needed for the selection of the predominant conformations for (R)-malathion and significantly improves the accuracy of the determination of absolute configuration.

  14. Fate of diradicals in the caldera: stereochemistry of thermal stereomutation and ring enlargement in cis- and trans-1-cyano-2(E)-propenylcyclopropanes.

    PubMed

    von E Doering, William; Barsa, Edward Albert

    2004-10-06

    This study of thermally induced stereomutation and ring enlargement in both (-)-trans-1-cyano-2(E)-propenylcyclopropane [(-)-trans-1] and (+)-cis-1-cyano-2(E)-propenylcyclopropane [(+)-cis-1] to cyclopentenes definitively contraindicates the usefulness of Woodward-Hoffmann rules of orbital symmetry as a theoretical basis for predicting the stereochemistry of the products. From both diastereomers, the same (+)-trans-4-cyano-3-methylcyclopentene [(+)-trans-2] is the major product among the four diastereomeric products, "allowed" and formally the result of a single internal rotation of the cyano-bearing carbon atom from (-)-trans-1, "forbidden" and the result of zero internal rotations from (+)-cis-1. Stereomutation and ring enlargement are discussed in detail in terms of rotational propensity, thermodynamic preference, and the possible role of diradicals in transit and diradicals as intermediates in a caldera.

  15. Can Virtual Reality Increase the Realism of Role Plays Used to Teach College Women Sexual Coercion and Rape-Resistance Skills?

    ERIC Educational Resources Information Center

    Jouriles, Ernest N.; McDonald, Renee; Kullowatz, Antje; Rosenfield, David; Gomez, Gabriella S.; Cuevas, Anthony

    2009-01-01

    The present study evaluated whether virtual reality (VR) can enhance the realism of role plays designed to help college women resist sexual attacks. Sixty-two female undergraduate students were randomly assigned to either the Role Play (RP) or Virtual Role Play (VRP) conditions, which were differentiated only by the use of VR technology in the VRP…

  16. The effect of sugar stereochemistry on protein self-assembly: the case of β-casein micellization in different aldohexose solutions.

    PubMed

    Setter, Ofer; Livney, Yoav D

    2015-02-07

    Protein self-assembly applications, such as nanoencapsulation of drugs and nutraceuticals, require deep understanding of the parameters governing the micellization process, including the effects of ionic and non-ionic co-solutes, like salts and sugars respectively, which is often overlooked. Herein, with the aim of shedding light on the effect of nonionic cosolute stereochemistry on protein self-assembly, we studied the ternary system of water-protein-sugar by examining the concentration-dependent effects of three aldohexoses, d-glucose (Glu), d-galactose (Gal) and d-mannose (Man) and that of urea, on the micellization of beta casein (β-Cas), using pyrene as a fluorescent probe for the formation of hydrophobic domains. Pyrene's excitation spectra were recorded for several sets of samples with rising protein concentration (0-5 mg ml(-1)), each set with a different co-solute type and concentration. Critical micellization concentration (CMC) and cooperativity of micellization were evaluated according to changes in pyrene spectra as it partitioned from the aqueous environment to the hydrophobic cores of β-Cas micelles. All sugars examined lowered the CMC of β-Cas with increasing sugar concentration and with a diminishing degree of effectiveness (Glu > Gal > Man) which correlated well with the sugars' dynamic hydration number, defined by Uedaira, and correlated negatively with their hydrophobic to hydrophilic molecular surface ratio. These results support the hypothesis that sugars affect protein self-assembly through both changes in water structure and by hydrophobic interactions, both of which are evidenced to be highly sensitive to sugar stereochemistry.

  17. Chiral Cyclobutane β-Amino Acid-Based Amphiphiles: Influence of Cis/Trans Stereochemistry on Solution Self-Aggregation and Recognition.

    PubMed

    Sorrenti, Alessandro; Illa, Ona; Pons, Ramon; Ortuño, Rosa M

    2015-09-08

    Novel diastereomeric anionic amphiphiles based on the rigid cyclobutane β-amino acid scaffold have been synthesized and deeply investigated with the aim of generating new functional supramolecular architectures on the basis of the rational design of original amphiphilic molecules and the control of their self-assembly. The main interest has been focused on the effect that cis/trans stereochemistry exerts on their molecular organization and recognition. In diluted solutions, the relative stereochemistry mainly influences the headgroup solvation and anionic-charge stabilization, i.e., better stabilized in the cis diastereoisomer due to intramolecular hydrogen-bonding and/or charge-dipole interactions. This provokes differences in their physicochemical behavior (pKa, cmc, conductivity) as well as in the structural parameters of the spherical micelles formed. Although both diastereoisomers form fibers that evolve with time from the spherical micelles, they display markedly different morphology and kinetics of formation. In the lyotropic liquid crystal domain, the greatest differences are observed at the highest concentrations and can be ascribed to different hydrogen-bonding and molecular packing imposed by the stereochemical constraints. Remarkably, the spherical micelles of the two anionic surfactants show dramatically diverse enantioselection ability for bilirubin enantiomers. In addition, both the surfactants form heteroaggregates with bilirubin at submicellar concentrations but with a different expression of supramolecular chirality. This points out that the unlike relative configuration of the two surfactants influences their chiral recognition ability as well as the fashion in which chirality is expressed at the supramolecular level by controlling the molecular organization in both micellar aggregates and surfactant/bilirubin heteroaggregates. All these differential features can be appropriate and useful for the design and development of new soft materials with

  18. On the contributions of astroparticle physics to cosmology

    NASA Astrophysics Data System (ADS)

    Falkenburg, Brigitte

    2014-05-01

    Studying astroparticle physics sheds new light on scientific explanation and on the ways in which cosmology is empirically underdetermined or not. Astroparticle physics extends the empirical domain of cosmology from purely astronomical data to "multi-messenger astrophysics", i.e., measurements of all kinds of cosmic rays including very high energetic gamma rays, neutrinos, and charged particles. My paper investigates the ways in which these measurements contribute to cosmology and compares them with philosophical views about scientific explanation, the relation between theory and data, and scientific realism. The "standard models" of cosmology and particle physics lack of unified foundations. Both are "piecemeal physics" in Cartwright's sense, but contrary to her metaphysics of a "dappled world" the work in both fields of research aims at unification. Cosmology proceeds "top-down", from models to data and from large scale to small-scale structures of the universe. Astroparticle physics proceeds "bottom-up", from data taking to models and from subatomic particles to large-scale structures of the universe. In order to reconstruct the causal stories of cosmic rays and the nature of their sources, several pragmatic unifying strategies are employed. Standard views about scientific explanation and scientific realism do not cope with these "bottom-up" strategies and the way in which they contribute to cosmology. In addition it has to be noted that the shift to "multi-messenger astrophysics" transforms the relation between cosmological theory and astrophysical data in a mutually holistic way.

  19. On the Role of Mathematics in Physics

    NASA Astrophysics Data System (ADS)

    Quale, Andreas

    2011-03-01

    I examine the association between the observable physical world and the mathematical models of theoretical physics. These models will exhibit many entities that have no counterpart in the physical world, but which are still necessary for the mathematical description of physical systems. Moreover, when the model is applied to the analysis of a physical system, it will sometimes produce solutions that are unphysical—i.e. describe a physical system that simply cannot exist in the real world. It is argued that this poses a problem for the epistemic position of realism in physics: a mathematical theory that professes to give a correct description of physical reality should not contain such unrealistic objects. Some concrete examples are examined, and their implications for physics are discussed from a relativist epistemic perspective. I argue that the appearance of the unphysical entities and solutions also has significance for the teaching of physics. It is recommended that the students be exposed from the start to a relativist ontology, as advocated by the theory of radical constructivism; here the unphysical objects do not pose an epistemic problem.

  20. Effects of realism on extended violent and nonviolent video game play on aggressive thoughts, feelings, and physiological arousal.

    PubMed

    Barlett, Christopher P; Rodeheffer, Christopher

    2009-01-01

    Previous research has shown that playing violent video game exposure can increase aggressive thoughts, aggressive feelings, and physiological arousal. This study compared the effects that playing a realistic violent, unrealistic violent, or nonviolent video game for 45 min has on such variables. For the purpose of this study, realism was defined as the probability of seeing an event in real life. Participants (N=74; 39 male, 35 female) played either a realistic violent, unrealistic violent, or nonviolent video game for 45 min. Aggressive thoughts and aggressive feelings were measured four times (every 15 min), whereas arousal was measured continuously. The results showed that, though playing any violent game stimulated aggressive thoughts, playing a more realistic violent game stimulated significantly more aggressive feelings and arousal over the course of play.

  1. A Study for Visual Realism of Designed Pictures on Computer Screens by Investigation and Brain-Wave Analyses.

    PubMed

    Wang, Lan-Ting; Lee, Kun-Chou

    2016-08-01

    In this article, the visual realism of designed pictures on computer screens is studied by investigation and brain-wave analyses. The practical electroencephalogram (EEG) measurement is always time-varying and fluctuating so that conventional statistical techniques are not adequate for analyses. This study proposes a new scheme based on "fingerprinting" to analyze the EEG. Fingerprinting is a technique of probabilistic pattern recognition used in electrical engineering, very like the identification of human fingerprinting in a criminal investigation. The goal of this study was to assess whether subjective preference for pictures could be manifested physiologically by EEG fingerprinting analyses. The most important advantage of the fingerprinting technique is that it does not require accurate measurement. Instead, it uses probabilistic classification. Participants' preference for pictures can be assessed using fingerprinting analyses of physiological EEG measurements.

  2. Scientist's Idealism Vs. User's Realism for Orthorectification of Full Radarsat-2/Compact RCM Polarimetric Data with DSM

    NASA Astrophysics Data System (ADS)

    Toutin, Thierry; Wang, Huili; Charbonneau, Francois; Schmitt, Carla

    2013-08-01

    This paper presented two methods for the orthorectification of full/compact polarimetric SAR data: the polarimetric processing is performed in the image space (scientist's idealism) or in the ground space (user's realism) before or after the geometric processing, respectively. Radarsat-2 (R2) fine-quad and simulated very high-resolution RCM data acquired with different look angles over a hilly relief study site were processed using accurate lidar digital surface model. Quantitative evaluations between the two methods as a function of different geometric and radiometric parameters were performed to evaluate the impact during the orthorectification. The results demonstrated that the ground-space method can be safely applied to polarimetric R2 SAR data with an exception with the steep look angles and steep terrain slopes. On the other hand, the ground-space method cannot be applied to simulated compact RCM data due to 17dB noise floor and oversampling.

  3. On Physical Properties of Tetraether Lipid Membranes: Effects of Cyclopentane Rings

    PubMed Central

    Chong, Parkson Lee-Gau; Ayesa, Umme; Prakash Daswani, Varsha; Hur, Ellah Chay

    2012-01-01

    This paper reviews the recent findings related to the physical properties of tetraether lipid membranes, with special attention to the effects of the number, position, and configuration of cyclopentane rings on membrane properties. We discuss the findings obtained from liposomes and monolayers, composed of naturally occurring archaeal tetraether lipids and synthetic tetraethers as well as the results from computer simulations. It appears that the number, position, and stereochemistry of cyclopentane rings in the dibiphytanyl chains of tetraether lipids have significant influence on packing tightness, lipid conformation, membrane thickness and organization, and headgroup hydration/orientation. PMID:23028246

  4. Stereochemistry of Pd(II)-Catalyzed THF Ring Formation of ε-Hydroxy Allylic Alcohols and Synthesis of 2,3,5-Trisubstituted and 2,3,4,5-Tetrasubstituted Tetrahydrofurans.

    PubMed

    Murata, Yuki; Uenishi, Jun'ichi

    2016-09-02

    Pd(II)-catalyzed ring formation of 2,3,5-trisubstituted and 2,3,4,5-tetrasubstituted tetrahydrofurans is described. Oxypalladation of a chiral ε-hydroxy allylic alcohol provides a 5-alkenyltetrahydrofuran ring in excellent yields via a 5-exo-trigonal process. Nine substrates including six secondary allylic alcohols and three primary allylic alcohols with or without an additional secondary hydroxy substituent at the γ-position have been examined. Their structures are restricted by a 2,2,4,4-tetraisopropyl-1,3,5,2,4-trioxadisilocane ring. The stereochemistry of the resulting tetrahydrofuran products was determined by chemical transformation. The reaction mechanism is discussed on the basis of the stereochemical results. The steps in the chiral allylic alcohol directed or the nucleophilic alcohol directed facial selection for the formation of the alkene-Pd(II)-π-complex, the cis-oxypalladation, and a syn-elimination mechanism account for the observed stereochemistry of the reaction.

  5. Enantiomeric Free Radicals and Enzymatic Control of Stereochemistry in a Radical Mechanism: the Case of Lysine 2,3-aminomutases †

    PubMed Central

    Behshad, E.; Ruzicka, F.J; Mansoorabadi, S.; Chen, D.; Reed, G.H; Frey, P.A.

    2008-01-01

    The product of yjeK in Escherichia coli is a homolog of lysine 2,3-aminomutase (LAM) from Clostridium subterminale SB4, and both enzymes catalyze the isomerization of (S)- but not (R)-α-lysine by radical mechanisms. The turnover number for LAM from E. coli is 5.0 min−1, 0.1% of the value for clostridial LAM. The reaction of E. coli LAM with (S)-α-[3,3,4,4,5,5,6,6- 2H8]lysine proceeds with a kinetic isotope effect of kH/kD = 1.4, suggesting that hydrogen transfer is not rate limiting. The product of the E. coli enzyme is (R)-β-lysine, the enantiomer of the clostridial product. β-Lysine-related radicals are observed in the reactions of both enzymes by electron paramagnetic resonance (EPR). The radical in the reaction of clostridial LAM has the (S)- configuration, whereas that in the reaction of E. coli LAM has the (R)-configuration. Moreover, the conformations of the β-lysine-related radicals at the active sites of E. coli and clostridial LAM are different. The nuclear hyperfine splitting between the C3-hydrogen and the unpaired electron at C2 shows the dihedral angle to be 6°, unlike the 77° reported for the analogous radical bound to the clostridial enzyme. Reaction of (S)-4-thialysine produces a substrate-related radical in the steady state of E. coli LAM, as in the action of the clostridial enzyme. While (S)-β-lysine is not a substrate for E. coli LAM, it undergoes hydrogen abstraction to form an (S)-β-lysine-related radical with the same stereochemistry of hydrogen transfer from C2 of (S)-β-lysine to the 5′-deoxyadenosyl radical as in the action of the clostridial enzyme. The resulting β-lysyl radical has a different conformation than that at the active site of clostridial LAM. All evidence indicates that the opposite stereochemistry displayed by the E. coli LAM is determined by the conformation of the lysine side chain in the active site. Stereochemical models for the actions of LAM from C. subterminale and E. coli are presented. PMID:17042480

  6. What makes a message real? The effects of perceived realism of alcohol- and drug-related messages on personal probability estimation.

    PubMed

    Cho, Hyunyi; Shen, Lijiang; Wilson, Kari M

    2013-03-01

    Perceived lack of realism in alcohol advertising messages promising positive outcomes and antialcohol and antidrug messages portraying negative outcomes of alcohol consumption has been a cause for public health concern. This study examined the effects of perceived realism dimensions on personal probability estimation through identification and message minimization. Data collected from college students in U.S. Midwest in 2010 (N = 315) were analyzed with multilevel structural equation modeling. Plausibility and narrative consistency mitigated message minimization, but they did not influence identification. Factuality and perceptual quality influenced both message minimization and identification, but their effects were smaller than those of typicality. Typicality was the strongest predictor of probability estimation. Implications of the results and suggestions for future research are provided.

  7. Revolution or Realism? United States-Iran Relations in the Post-Cold War Era

    DTIC Science & Technology

    1993-12-01

    a onally, psychologically and physically emasculated by the revolution. As the principal group supportimg the monarchy, the armed forces were viewed...1130Hashum, p. 5. 131Adgo, p. 34. 13 2bA, p. 34. 135 133 FWipt from Researh Service quoted by Ahmed Hashim, "Is Iran a Milay Threatr, khan i, Fonnu on

  8. MMORPG escapism predicts decreased well-being: examination of gaming time, game realism beliefs, and online social support for offline problems.

    PubMed

    Kaczmarek, Lukasz D; Drążkowski, Dariusz

    2014-05-01

    Massively multiplayer online role-playing game (MMORPG) escapists are individuals who indulge in the MMORPG environment to avoid real world problems. Though a relationship between escapism and deteriorated well-being has been established, little is known about particular pathways that mediate this relationship. In the current study, we examined this topic by testing an integrative model of MMORPG escapism, which includes game realism beliefs, gaming time, offline social support, and online social support for offline problems. MMORPG players (N=1,056) completed measures of escapist motivation, game realism beliefs, social support, well-being, and reported gaming time. The tested structural equation model had a good fit to the data. We found that individuals with escapist motivation endorsed stronger game realism beliefs and spent more time playing MMORPGs, which, in turn, increased online support but decreased offline social support. Well-being was favorably affected by both online and offline social support, although offline social support had a stronger effect. The higher availability of online social support for offline problems did not compensate for the lower availability of offline support among MMORPG escapists. Understanding the psychological factors related to depletion of social resources in MMORPG players can help optimize MMORPGs as leisure activities.

  9. Differential effects of face-realism and emotion on event-related brain potentials and their implications for the uncanny valley theory

    NASA Astrophysics Data System (ADS)

    Schindler, Sebastian; Zell, Eduard; Botsch, Mario; Kissler, Johanna

    2017-03-01

    Cartoon characters are omnipresent in popular media. While few studies have scientifically investigated their processing, in computer graphics, efforts are made to increase realism. Yet, close approximations of reality have been suggested to evoke sometimes a feeling of eeriness, the “uncanny valley” effect. Here, we used high-density electroencephalography to investigate brain responses to professionally stylized happy, angry, and neutral character faces. We employed six face-stylization levels varying from abstract to realistic and investigated the N170, early posterior negativity (EPN), and late positive potential (LPP) event-related components. The face-specific N170 showed a u-shaped modulation, with stronger reactions towards both most abstract and most realistic compared to medium-stylized faces. For abstract faces, N170 was generated more occipitally than for real faces, implying stronger reliance on structural processing. Although emotional faces elicited highest amplitudes on both N170 and EPN, on the N170 realism and expression interacted. Finally, LPP increased linearly with face realism, reflecting activity increase in visual and parietal cortex for more realistic faces. Results reveal differential effects of face stylization on distinct face processing stages and suggest a perceptual basis to the uncanny valley hypothesis. They are discussed in relation to face perception, media design, and computer graphics.

  10. Differential effects of face-realism and emotion on event-related brain potentials and their implications for the uncanny valley theory

    PubMed Central

    Schindler, Sebastian; Zell, Eduard; Botsch, Mario; Kissler, Johanna

    2017-01-01

    Cartoon characters are omnipresent in popular media. While few studies have scientifically investigated their processing, in computer graphics, efforts are made to increase realism. Yet, close approximations of reality have been suggested to evoke sometimes a feeling of eeriness, the “uncanny valley” effect. Here, we used high-density electroencephalography to investigate brain responses to professionally stylized happy, angry, and neutral character faces. We employed six face-stylization levels varying from abstract to realistic and investigated the N170, early posterior negativity (EPN), and late positive potential (LPP) event-related components. The face-specific N170 showed a u-shaped modulation, with stronger reactions towards both most abstract and most realistic compared to medium-stylized faces. For abstract faces, N170 was generated more occipitally than for real faces, implying stronger reliance on structural processing. Although emotional faces elicited highest amplitudes on both N170 and EPN, on the N170 realism and expression interacted. Finally, LPP increased linearly with face realism, reflecting activity increase in visual and parietal cortex for more realistic faces. Results reveal differential effects of face stylization on distinct face processing stages and suggest a perceptual basis to the uncanny valley hypothesis. They are discussed in relation to face perception, media design, and computer graphics. PMID:28332557

  11. Differential effects of face-realism and emotion on event-related brain potentials and their implications for the uncanny valley theory.

    PubMed

    Schindler, Sebastian; Zell, Eduard; Botsch, Mario; Kissler, Johanna

    2017-03-23

    Cartoon characters are omnipresent in popular media. While few studies have scientifically investigated their processing, in computer graphics, efforts are made to increase realism. Yet, close approximations of reality have been suggested to evoke sometimes a feeling of eeriness, the "uncanny valley" effect. Here, we used high-density electroencephalography to investigate brain responses to professionally stylized happy, angry, and neutral character faces. We employed six face-stylization levels varying from abstract to realistic and investigated the N170, early posterior negativity (EPN), and late positive potential (LPP) event-related components. The face-specific N170 showed a u-shaped modulation, with stronger reactions towards both most abstract and most realistic compared to medium-stylized faces. For abstract faces, N170 was generated more occipitally than for real faces, implying stronger reliance on structural processing. Although emotional faces elicited highest amplitudes on both N170 and EPN, on the N170 realism and expression interacted. Finally, LPP increased linearly with face realism, reflecting activity increase in visual and parietal cortex for more realistic faces. Results reveal differential effects of face stylization on distinct face processing stages and suggest a perceptual basis to the uncanny valley hypothesis. They are discussed in relation to face perception, media design, and computer graphics.

  12. ns2np4 (n = 4, 5) lone pair triplets whirling in M*F2E3 (M* = Kr, Xe): Stereochemistry and ab initio analyses

    NASA Astrophysics Data System (ADS)

    Galy, Jean; Matar, Samir F.

    2017-02-01

    The stereochemistry of ns2np4 (n = 4, 5) lone pair LP characterizing noble gas Kr and Xe (labeled M*) in M*F2 difluorides is examined within coherent crystal chemistry and ab initio visualizations. M*2+ in such oxidation state brings three lone pairs (E) and difluorides are formulated M*F2E3. The analyses use electron localization function (ELF) obtained within density functional theory calculations showing the development of the LP triplets whirling {E3} quantified in the relevant chemical systems. Detailed ELF data analyses allowed showing that in α KrF2E3 and isostructural XeF2E3 difluorides the three E electronic clouds merge or hybridize into a torus and adopt a perfect gyration circle with an elliptical section, while in β KrF2 the network architecture deforms the whole torus into an ellipsoid shape. Original precise metrics are provided for the torus in the different compounds under study. In KrF2 the geometric changes upon β → α phase transition is schematized and mechanisms for the transformation with temperature or pressure are proposed. The results are further highlighted by electronic band structure calculations which show similar features of equal band gaps of 3 eV in both α and β KrF2 and a reorganization of frontier orbitals due to the different orientations of the F-Kr-F linear molecule in the two tetragonal structures.

  13. Effects of stereochemistry, saturation, and hydrocarbon chain length on the ability of synthetic constrained azacyclic sphingolipids to trigger nutrient transporter down-regulation, vacuolation, and cell death.

    PubMed

    Perryman, Michael S; Tessier, Jérémie; Wiher, Timothy; O'Donoghue, Heather; McCracken, Alison N; Kim, Seong M; Nguyen, Dean G; Simitian, Grigor S; Viana, Matheus; Rafelski, Susanne; Edinger, Aimee L; Hanessian, Stephen

    2016-09-15

    Constrained analogs containing a 2-hydroxymethylpyrrolidine core of the natural sphingolipids sphingosine, sphinganine, N,N-dimethylsphingosine and N-acetyl variants of sphingosine and sphinganine (C2-ceramide and dihydro-C2-ceramide) were synthesized and evaluated for their ability to down-regulate nutrient transporter proteins and trigger cytoplasmic vacuolation in mammalian cells. In cancer cells, the disruptions in intracellular trafficking produced by these sphingolipids lead to cancer cell death by starvation. Structure activity studies were conducted by varying the length of the hydrocarbon chain, the degree of unsaturation and the presence or absence of an aryl moiety on the appended chains, and stereochemistry at two stereogenic centers. In general, cytotoxicity was positively correlated with nutrient transporter down-regulation and vacuolation. This study was intended to identify structural and functional features in lead compounds that best contribute to potency, and to develop chemical biology tools that could be used to isolate the different protein targets responsible for nutrient transporter loss and cytoplasmic vacuolation. A molecule that produces maximal vacuolation and transporter loss is expected to have the maximal anti-cancer activity and would be a lead compound.

  14. Stereochemistry of amino acid spacers determines the pharmacokinetics of (111)In-DOTA-minigastrin analogues for targeting the CCK2/gastrin receptor.

    PubMed

    Kolenc Peitl, Petra; Tamma, MariaLuisa; Kroselj, Marko; Braun, Friederike; Waser, Beatrice; Reubi, Jean Claude; Sollner Dolenc, Marija; Maecke, Helmut R; Mansi, Rosalba

    2015-06-17

    The metabolic instability and high kidney retention of minigastrin (MG) analogues hamper their suitability for use in peptide-receptor radionuclide therapy of CCK2/gastrin receptor-expressing tumors. High kidney retention has been related to N-terminal glutamic acids and can be substantially reduced by coinjection of polyglutamic acids or gelofusine. The aim of the present study was to investigate the influence of the stereochemistry of the N-terminal amino acid spacer on the enzymatic stability and pharmacokinetics of (111)In-DOTA-(d-Glu)6-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 ((111)In-PP11-D) and (111)In-DOTA-(l-Glu)6-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2 ((111)In-PP11-L). Using circular dichroism measurements, we demonstrate the important role of secondary structure on the pharmacokinetics of the two MG analogues. The higher in vitro serum stability together with the improved tumor-to-kidney ratio of the (d-Glu)6 congener indicates that this MG analogue might be a good candidate for further clinical study.

  15. Dynamic NMR and Quantum-Chemical Study of the Stereochemistry and Stability of the Chiral MoO2(acac)2 Complex in Solution.

    PubMed

    Conte, Marco; Hippler, Michael

    2016-09-01

    The stereochemistry and dynamics of MoO2(acac)2 in benzene, chloroform, and toluene were investigated by variable temperature (1)H NMR, density functional theory (SOGGA11-X, B3LYP), and ab initio (MP2) methods. In solution, an equilibrium between two chiral enantiomers with C2 symmetry was identified, Λ-cis-MoO2(acac)2 and Δ-cis-MoO2(acac)2. The two enantiomers are connected via achiral cis transition states that switch the enantiomeric conformations via a Ray-Dutt, Bailar, and a newly described racemization twisting mechanism. All three mechanisms have similar calculated activation energies. Activation parameters Ea, ΔH(‡), and ΔS(‡) were experimentally determined for the exchange process, with a small, negative ΔS(‡), and a positive ΔH(‡) of 68.1 kJ mol(-1) in benzene, 54.9 kJ mol(-1) in chloroform, and 60.6 kJ mol(-1) in toluene, in reasonable general agreement with the calculations. Trans configurations of MoO2(acac)2 are very much higher in energy than cis and are not relevant in the temperature range experimentally studied, 243-340 K. The enantiomers interconvert within seconds near room temperature and much faster at elevated temperatures. Racemization will thus prevent the use of enantiomerically pure MoO2(acac)2 for chiral catalysis under practical conditions.

  16. Stereochemistry and solid-state structure of an intrinsically chiral meso-patterned porphyrin: case study by NMR and single-crystal X-ray diffraction analysis.

    PubMed

    Yang, Liguo; Zhou, Yang; Zhu, Mengliang; Zhao, Luyang; Wei, Liye; Bian, Yongzhong

    2013-10-04

    A C1-symmerical meso-substituted ABCD-type porphyrin, [5-phenyl-10-(2-hydroxynaphthyl)-15-(4-hydroxyphenyl)porphyrinato]zinc(II) (1), has been synthesized and characterized. The molecular structure of 1 has been determined by single-crystal X-ray diffraction analysis. The complex 1 crystallizes in a triclinic system with one pair of enantiomeric molecules per unit cell. Resolution of the racemic mixture has been achieved by chiral HPLC techniques. In particular, the absolute configurations of the enantiomers have been assigned from NMR spectroscopic analysis with L-Phe-OMe as the chiral solvating agent (CSA). The assignments have also been unambiguously confirmed by single-crystal X-ray diffraction analysis. The present results suggest that the CSA-NMR anisotropy strategy is applicable for the stereochemistry determination of chiral host-guest complexes with multiple intermolecular interactions. In addition, the multiple intermolecular interactions between the enantiomerically pure porphyrin S-1 and L-Phe-OMe are proved in the solid state by single-crystal X-ray diffraction analysis.

  17. The Relationship Between Realism in Air Force Exercises and Combat Readiness

    DTIC Science & Technology

    1994-09-01

    confronted with in a contingency or combat situation. Reality consists of numerous physical and psychological elements which include factors such as time...unsuccessful infantrymen in combat and simulated combat situations. Although developed as a psychological study of the individual behavior trait- which 2...Company, Inc., 31 December 1951. 3. Cicarelli , James. "The Future of Economics: A Delphi Study," Technological Forecasting and Social Change. 25: 139-!5

  18. Shock treatment: using immersive digital realism to restage and re-examine milgram's 'obedience to authority' research.

    PubMed

    Haslam, S Alexander; Reicher, Stephen D; Millard, Kathryn

    2015-01-01

    Attempts to revisit Milgram's 'Obedience to Authority' (OtA) paradigm present serious ethical challenges. In recent years new paradigms have been developed to circumvent these challenges but none involve using Milgram's own procedures and asking naïve participants to deliver the maximum level of shock. This was achieved in the present research by using Immersive Digital Realism (IDR) to revisit the OtA paradigm. IDR is a dramatic method that involves a director collaborating with professional actors to develop characters, the strategic withholding of contextual information, and immersion in a real-world environment. 14 actors took part in an IDR study in which they were assigned to conditions that restaged Milgrams's New Baseline ('Coronary') condition and four other variants. Post-experimental interviews also assessed participants' identification with Experimenter and Learner. Participants' behaviour closely resembled that observed in Milgram's original research. In particular, this was evidenced by (a) all being willing to administer shocks greater than 150 volts, (b) near-universal refusal to continue after being told by the Experimenter that "you have no other choice, you must continue" (Milgram's fourth prod and the one most resembling an order), and (c) a strong correlation between the maximum level of shock that participants administered and the mean maximum shock delivered in the corresponding variant in Milgram's own research. Consistent with an engaged follower account, relative identification with the Experimenter (vs. the Learner) was also a good predictor of the maximum shock that participants administered.

  19. Chiral Cyclobutane β-Amino Acid-Based Amphiphiles: Influence of Cis/Trans Stereochemistry on Condensed Phase and Monolayer Structure.

    PubMed

    Sorrenti, Alessandro; Illa, Ona; Ortuño, Rosa M; Pons, Ramon

    2016-07-12

    New diastereomeric nonionic amphiphiles, cis- and trans-1, based on an optically pure cyclobutane β-amino ester moiety have been investigated to gain insight into the influence exerted by cis/trans stereochemistry and stereochemical constraints on the physicochemical behavior, molecular organization, and morphology of their Langmuir monolayers and dry solid states. All these features are relevant to the rational design of functional materials. trans-1 showed a higher thermal stability than cis-1. For the latter, a higher fluidity of its monolayers was observed when compared with the films formed by trans-1 whose BAM images revealed the formation of condensed phase domains with a dendritic shape, which are chiral, and all of them feature the same chiral sign. Although the formation of LC phase domains was not observed by BAM for cis-1, compact dendritic crystals floating on a fluid subphase were observed beyond the collapse, which are attributable to multilayered 3D structures. These differences can be explained by the formation of hydrogen bonds between the amide groups of consecutive molecules allowing the formation of extended chains for trans-1 giving ordered arrangements. However, for cis-1, this alignment coexists with another one that allows the simultaneous formation of two hydrogen bonds between the amide and the ester groups of adjacent molecules. In addition, the propensity to form intramolecular hydrogen bonds must be considered to justify the formation of different patterns of hydrogen bonding and, consequently, the formation of less ordered phases. Those characteristics are congruent also with the results obtained from SAXS-WAXS experiments which suggest a more bent configuration for cis-1 than for trans-1.

  20. Stereochemistry of LinB-catalyzed biotransformation of δ-HBCD to 1R,2R,5S,6R,9R,10S-pentabromocyclododecanol.

    PubMed

    Heeb, Norbert V; Zindel, Daniel; Graf, Heidi; Azara, Valeria; Schweizer, W Bernd; Geueke, Birgit; Kohler, Hans-Peter E; Lienemann, Peter

    2013-02-01

    The haloalkane dehalogenase LinB from Sphingobium indicum B90A converts β-hexachlorocyclohexane (β-HCH), the most persistent HCH stereoisomer, to mono- and dihydroxylated metabolites. Recently, we reported that LinB also transforms α-, β- and γ-hexabromocyclododecanes (HBCDs), which are structurally related to HCHs. Here, we show that LinB catalyzes the hydroxylation of δ-HBCD to two pentabromocyclododecanols (PBCDOHs) and two tetrabromocyclododecadiols (TBCDDOHs). The stereochemistry of this enzymatic transformation was deduced from XRD crystal structure data of the substrate δ-HBCD and α(2)-PBCDOH, one of the biotransformation products. Five stereocenters of δ-HBCD are unchanged but the one at C6 is converted to an alcohol with inversion from S- to R-configuration in a nucleophilic, S(N)2-like substitution reaction. Only α(2)-PBCDOH with the 1R,2R,5S,6R,9R,10S-configuration is obtained but not its enantiomer. With only two of the 64 PBCDOHs formed, these transformations indeed are regio- and stereoselective. A conformational analysis revealed that the triple-turn motive, which is predominant in δ-HBCD and in several other HBCD stereoisomers, is also found in the product. This shows that LinB preferentially converted reactive bromine atoms but not those in the conserved triple-turn motive. The widespread contamination with HCHs triggered the bacterial evolution of dehalogenases which acquired the ability to convert these pollutants and their metabolites. We here demonstrate that LinB of S. indicum also transforms HBCDs regio- and stereoselectively following a similar mechanism.

  1. Stereochemistry of enzymatic transformations of (+)β- and (-)β-HBCD with LinA2--a HCH-degrading bacterial enzyme of Sphingobium indicum B90A.

    PubMed

    Heeb, Norbert V; Wyss, Simon A; Geueke, Birgit; Fleischmann, Thomas; Kohler, Hans-Peter E; Bernd Schweizer, W; Moor, Heidi; Lienemann, Peter

    2015-03-01

    LinA2, a bacterial enzyme expressed in various Sphingomonadaceae, catalyzes the elimination of HCl from hexachlorocyclohexanes (HCHs) and, as discussed here, the release of HBr from certain hexabromocyclododecanes (HBCDs). Both classes of compounds are persistent organic pollutants now regulated under the Stockholm Convention. LinA2 selectively catalyzes the transformation of β-HBCDs; other stereoisomers like α-, γ-, and δ-HBCDs are not converted. The transformation of (-)β-HBCD is considerably faster than that of its enantiomer. Here, we present the XRD crystal structure of 1E,5S,6S,9R,10S-pentabromocyclododecene (PBCDE) and demonstrate that its enantiomer with the 1E,5R,6R,9S,10R-configuration is the only metabolite formed during LinA2-catalyzed dehydrobromination of (-)β-HBCD. Formation of this product can be rationalized by HBr elimination at C5 and C6. A reasonable enzyme-substrate complex with the catalytic dyad His-73 and Asp-25 approaching the hydrogen at C6 and a cationic pocket of Lys-20, Try-42 and Arg-129 binding the leaving bromine at C5 was found from in silico docking experiments. A second PBCDE of yet unknown configuration was obtained from (+)β-HBCD. We predicted its stereochemistry to be 1E,5S,6S,9S,10R-PBCDE from docking experiments. The enzyme-substrate complex obtained from LinA2 and an activated conformation of (+)β-HBCD allows the HBr elimination at C9 and C10 leading to the predicted product. Both modeled enzyme-substrate complexes are in line with 1,2-diaxial HBr eliminations. In conclusion, LinA2, a bacterial enzyme of the HCH-degrading strain Sphingobium indicum B90A was able to stereoselectively convert β-HBCDs. Configurations of both PBCDE metabolites were predicted by molecular docking experiments and confirmed in one case by XRD data.

  2. Inversion of the stereochemistry around the sulfur atom of the axial methionine side chain through alteration of amino acid side chain packing in Hydrogenobacter thermophilus cytochrome C552 and its functional consequences.

    PubMed

    Tai, Hulin; Tonegawa, Ken; Shibata, Tomokazu; Hemmi, Hikaru; Kobayashi, Nagao; Yamamoto, Yasuhiko

    2013-07-16

    In cytochrome c, the coordination of the axial Met Sδ atom to the heme Fe atom occurs in one of two distinctly different stereochemical manners, i.e., R and S configurations, depending upon which of the two lone pairs of the Sδ atom is involved in the bond; hence, the Fe-coordinated Sδ atom becomes a chiral center. In this study, we demonstrated that an alteration of amino acid side chain packing induced by the mutation of a single amino acid residue, i.e., the A73V mutation, in Hydrogenobacter thermophilus cytochrome c552 (HT) forces the inversion of the stereochemistry around the Sδ atom from the R configuration [Travaglini-Allocatelli, C., et al. (2005) J. Biol. Chem. 280, 25729-25734] to the S configuration. Functional comparison between the wild-type HT and the A73V mutant possessing the R and S configurations as to the stereochemistry around the Sδ atom, respectively, demonstrated that the redox potential (Em) of the mutant at pH 6.00 and 25 °C exhibited a positive shift of ∼20 mV relative to that of the wild-type HT, i.e., 245 mV, in an entropic manner. Because these two proteins have similar enthalpically stabilizing interactions, the difference in the entropic contribution to the Em value between them is likely to be due to the effect of the conformational alteration of the axial Met side chain associated with the inversion of the stereochemistry around the Sδ atom due to the effect of mutation on the internal mobility of the loop bearing the axial Met. Thus, the present study demonstrated that the internal mobility of the loop bearing the axial Met, relevant to entropic control of the redox function of the protein, is affected quite sensitively by the contextual stereochemical packing of amino acid side chains in the proximity of the axial Met.

  3. Physical Development: Thinking Physically

    ERIC Educational Resources Information Center

    Strickland, Erik

    2005-01-01

    Children grow and develop physically according to their own experiences, characteristics, and abilities. Physical development is so important and the environment should allow each child to find her space in the sunshine. This can be done by: (1) creating the right outdoor environment; (2) allowing children time to use it; (3) encouraging movement…

  4. Total Synthesis of the GRP78-Downregulatory Macrolide (+)-Prunustatin A, the Immunosuppressant (+)-SW-163A, and a JBIR-04 Diastereoisomer That Confirms JBIR-04 Has Nonidentical Stereochemistry to (+)-Prunustatin A.

    PubMed

    Manaviazar, Soraya; Nockemann, Peter; Hale, Karl J

    2016-06-17

    A unified total synthesis of the GRP78-downregulator (+)-prunustatin A and the immunosuppressant (+)-SW-163A based upon [1 + 1 + 1 + 1]-fragment condensation and macrolactonization between O(4) and C(5) is herein described. Sharpless asymmetric dihydroxylation was used to set the C(2) stereocenter present in both targets. In like fashion, coupling of the (+)-prunustatin A macrolide amine with benzoic acid furnished a JBIR-04 diastereoisomer whose NMR spectra did not match those of JBIR-04, thus confirming that it has different stereochemistry than (+)-prunustatin A.

  5. Inversion of the Side-Chain Stereochemistry of Indvidual Thr or Ile Residues in a Protein Molecule: Impact on the Folding, Stability, and Structure of the ShK Toxin.

    PubMed

    Dang, Bobo; Shen, Rong; Kubota, Tomoya; Mandal, Kalyaneswar; Bezanilla, Francisco; Roux, Benoit; Kent, Stephen B H

    2017-03-13

    ShK toxin is a cysteine-rich 35-residue protein ion-channel ligand isolated from the sea anemone Stichodactyla helianthus. In this work, we studied the effect of inverting the side chain stereochemistry of individual Thr or Ile residues on the properties of the ShK protein. Molecular dynamics simulations were used to calculate the free energy cost of inverting the side-chain stereochemistry of individual Thr or Ile residues. Guided by the computational results, we used chemical protein synthesis to prepare three ShK polypeptide chain analogues, each containing either an allo-Thr or an allo-Ile residue. The three allo-Thr or allo-Ile-containing ShK polypeptides were able to fold into defined protein products, but with different folding propensities. Their relative thermal stabilities were measured and were consistent with the MD simulation data. Structures of the three ShK analogue proteins were determined by quasi-racemic X-ray crystallography and were similar to wild-type ShK. All three ShK analogues retained ion-channel blocking activity.

  6. Realism in Exercises

    DTIC Science & Technology

    1989-09-01

    me expand on this thesis just a bit. My contention is that in every exercise, even the ones like Wintex- Cimex which are supposed to test the logistics...Wintex- Cimex and Gallant Eagle, occur every other year and in the off-year there is a complimentary FTX. Addit-ionally, there is usually one big CPX...spares calculations, and other logistics concerns. 3-2 Observation and Participation The researcher observed the winter exercise known as Wintex- Cimex

  7. Critical Aesthetic Realism

    ERIC Educational Resources Information Center

    McMahon, Jennifer A.

    2011-01-01

    A clear-cut concept of the aesthetic is elusive. Kant's "Critique of Judgment" presents one of the more comprehensive aesthetic theories from which one can extract a set of features, some of which pertain to aesthetic experience and others to the logical structure of aesthetic judgment. When considered together, however, these features present a…

  8. Grasping the Concepts of Stereochemistry.

    ERIC Educational Resources Information Center

    Barta, Nancy S.; Stille, John R.

    1994-01-01

    Presents an effective means of determining the R or S configuration of chiral molecules using the Cahn Ingold Prelog (CIP) sequence rules to establish substituent priority and use of the ultimate model of chirality, the hands, to aid in the direct correlation and assignment of relative configuration. (ZWH)

  9. DFT Investigation of the Mechanism and Stereochemistry of Electrophilic Transannular Addition Reaction of Chlorine to Bisbenzotetracyclo[6.2.2.23,6 .02,7]tetradeca-4,9,11,13-tetraene.

    PubMed

    Abbasoglu, Rza

    2010-12-01

    The mechanism and stereochemistry of electrophilic addition of chlorine to bisbenzotetracyclo[6.2.2.23,6.02,7]tetradeca-4,9,11,13-tetraene (BBTT) molecule were investigated by DFT methods. The geometry and the electronic structure of BBTT molecule was studied by DFT/B3LYP method using the 6-311G(d) and 6-311++G(d,p) basis sets. The double bonds of BBTT molecule are endo-pyramidalized. The structure and stability of the cationic intermediates and products of the addition reaction were investigated by B3LYP/6-311G(d) and B3LYP/6-311+G(2d,p) methods. The solvent effect was evaluated using SCI-PCM method. The bridged chloronium cation is isomerized into the more stable nonclassical delocalized N- and U-type cations, and the difference between the stability of these cations is small. For the determination of the direction of addition reaction and the stereochemistry of the products, the stability of nonclassical delocalized N- and U-type ions and the structure of their cationic centres play a vital role for the determination of the direction of addition reaction and the stereochemistry of the products. Since the cationic centre of the N-type ion is in interaction with the benzene ring from the exo face, the nucleophilic attack of the chloride anion to this centre occurs from the endo face, and the exo,endo-isomer of the N-type product is obtained. The attack of chloride anion towards the cationic centre of U-type ion from the endo face is sterically hindered by the hydrogen atom, therefore the attack occurs from the exo face, which interacts with the benzene ring and the more stable exo,exo-isomer of U-type product is formed. Although, the U-type cation was 3.485 kcal mol-1 more stable than the N-type cation, the U-type product was 1.886 kcal mol-1 [SCI-PCM-B3LYP/6-311++G(2d,p)// B3LYP/6-311G(d)] less stable than the N-type product.

  10. A modified Wright-Fisher model that incorporates Ne: A variant of the standard model with increased biological realism and reduced computational complexity.

    PubMed

    Zhao, Lei; Gossmann, Toni I; Waxman, David

    2016-03-21

    The Wright-Fisher model is an important model in evolutionary biology and population genetics. It has been applied in numerous analyses of finite populations with discrete generations. It is recognised that real populations can behave, in some key aspects, as though their size that is not the census size, N, but rather a smaller size, namely the effective population size, Ne. However, in the Wright-Fisher model, there is no distinction between the effective and census population sizes. Equivalently, we can say that in this model, Ne coincides with N. The Wright-Fisher model therefore lacks an important aspect of biological realism. Here, we present a method that allows Ne to be directly incorporated into the Wright-Fisher model. The modified model involves matrices whose size is determined by Ne. Thus apart from increased biological realism, the modified model also has reduced computational complexity, particularly so when Ne⪡N. For complex problems, it may be hard or impossible to numerically analyse the most commonly-used approximation of the Wright-Fisher model that incorporates Ne, namely the diffusion approximation. An alternative approach is simulation. However, the simulations need to be sufficiently detailed that they yield an effective size that is different to the census size. Simulations may also be time consuming and have attendant statistical errors. The method presented in this work may then be the only alternative to simulations, when Ne differs from N. We illustrate the straightforward application of the method to some problems involving allele fixation and the determination of the equilibrium site frequency spectrum. We then apply the method to the problem of fixation when three alleles are segregating in a population. This latter problem is significantly more complex than a two allele problem and since the diffusion equation cannot be numerically solved, the only other way Ne can be incorporated into the analysis is by simulation. We have

  11. Sports physical

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000673.htm Sports physical To use the sharing features on this ... or routine checkups. Why do you Need a Sports Physical? The sports physical is done to: Find ...

  12. The influence of the stereochemistry of alanine residue on the solid state conformation and crystal packing of opioid peptides containing D-Ala or L-Ala in message domain--XRD and NMR study.

    PubMed

    Trzeciak-Karlikowska, Katarzyna; Bujacz, Anna; Ciesielski, Włodzimierz; Bujacz, Grzegorz D; Potrzebowski, Marek J

    2011-08-18

    In this work, an X-ray diffraction (XRD) and solid state NMR study of two tetrapeptides with different stereochemistry of alanine residue is presented using Tyr-(D-Ala)-Phe-Gly (1), an N-terminal sequence of opioid peptide dermorphin, and its biologically inactive analog Tyr-(L-Ala)-Phe-Gly (2). Single-crystal XRD proved that 1 crystallized under different conditions from exclusively one structure: a monoclinic crystal with P2(1) space group. In contrast, 2 very easily formed at least three crystallographic modifications, 2a (monoclinic P2(1)), 2b (orthorhombic P2(1)2(1)2) and 2c (tetragonal P4(1)2(1)2). Solid-state NMR spectroscopy was employed to investigate the structure and molecular dynamics of 1, 2a, and 2b. By employing different NMR experiments (dipolar dephasing and PILGRIM) and an analysis of the (13)C principal elements of the chemical shift tensor (CST), it was proven that the main skeleton of tetrapeptides is rigid, whereas significant differences in the molecular motion of the aromatic residues were observed. Comparing current data with those of previous studies (J. Phys. Chem. B2004, 108, 4535-4545 and Cryst. Growth Des. 2009, 9, 4050-4059), it can be assumed that an important preorganization mechanism anticipating the formation of peptide crystals containing D-Ala in sequence is the intramolecular CH-π interaction, which occurs for the amino acid with D stereochemistry. This effect may be responsible for the formation of only one crystallographic form of D-Ala peptides.

  13. Direct bis-arylation of cyclobutanecarboxamide via double C-H activation: an auxiliary-aided diastereoselective Pd-catalyzed access to trisubstituted cyclobutane scaffolds having three contiguous stereocenters and an all-cis stereochemistry.

    PubMed

    Parella, Ramarao; Gopalakrishnan, Bojan; Babu, Srinivasarao Arulananda

    2013-12-06

    An auxiliary-aided Pd-catalyzed highly diastereoselective double C-H activation and direct bis-arylation of methylene C(sp(3))-H bonds of cyclobutanecarboxamides and the syntheses of several novel trisubstituted cyclobutanecarboxamide scaffolds having an all-cis stereochemistry are reported. Extensive screening of various auxiliaries and reaction conditions was performed to firmly establish the optimized reaction conditions required for effecting the mono- or double C-H arylation of cyclobutanecarboxamides. The auxiliary-attached cyclobutanecarboxamides 15a, 15g, and 15h, prepared from the auxiliaries such as, 8-aminoquinoline, 2-(methylthio)aniline, and N',N'-dimethylethane-1,2-diamine were found to undergo an efficient direct bis-arylation. The Pd-catalyzed arylation reaction of N-(quinolin-8-yl)cyclobutanecarboxamide 15a with one equivalent or more of aryl iodides, afforded the corresponding bis-arylated cyclobutanecarboxamides 16a-y. Nevertheless, the Pd-catalyzed arylation of 15a with just 0.5 equiv of the aryl iodides 13a, 13b, 13e, and 13m, selectively gave the corresponding monoarylated cyclobutanecarboxamides 17a-17d. The Pd-catalyzed arylation of 15g or 15h with one equivalent or more of aryl iodides afforded the bis-arylated cyclobutanecarboxamides 19a-19c and 21a-21m, respectively. However, the Pd-catalyzed arylations of compounds 15g or 15h with just 0.5 equiv of aryl iodides were ineffective. The stereochemistry of compounds obtained in this work was unambiguously assigned from the X-ray structures of representative products.

  14. Actuality of transcendental æsthetics for modern physics

    NASA Astrophysics Data System (ADS)

    Petitot, Jean

    1. The more mathematics and physics unify themselves in the physico-mathematical modern theories, the more an objective epistemology becomes necessary. Only such a transcendental epistemology is able to thematize correctly the status of the mathematical determination of physical reality. 2. There exists a transcendental history of the synthetic a priori and of the construction of physical categories. 3. The transcendental approach allows to supersed Wittgenstein's and Carnap's antiplatonist thesis according to which pure mathematics are physically applicable only if they lack any descriptive, cognitive or objective, content and reduce to mere prescriptive and normative devices. In fact, pure mathematics are prescriptive-normative in physics because: (i) the categories of physical objectivity are prescriptive-normative, and (ii) their categorial content is mathematically “constructed” through a Transcendental Aesthetics. Only a transcendental approach make compatible, in the one hand, a grammatical conventionalism of Wittgensteinian or Carnapian type and, on the other hand, a platonist realism of Gödelian type. Mathematics are not a grammar of the world but a mathematical hermeneutics of the intuitive forms and of the categorial grammar of the world.

  15. Using the PhysX engine for Physics-based Virtual Surgery with Force Feedback

    PubMed Central

    Maciel, Anderson; Halic, Tansel; Lu, Zhonghua; Nedel, Luciana P.; De, Suvranu

    2010-01-01

    Background The development of modern surgical simulators is highly challenging as they must support complex simulation environments. The demand for higher realism in such simulators has driven researchers to adopt physics-based models which are computationally very demanding. This poses a major problem since real time interactions must permit graphical updates of 30 Hz and a much higher rate of 1 kHz for force feedback (haptics). Recently several physics engines have been developed which offer multi-physics simulation capabilities including rigid and deformable bodies, cloth and fluids. While such physics engines provide unique opportunities for the development of surgical simulators, their higher latencies, compared to what is necessary for real time graphics and haptics, offer significant barriers to their use in interactive simulation environments. Methods In this work, we propose solutions to this problem and demonstrate how a multimodal surgical simulation environment may be developed based on NVIDIA’s PhysX physics library. Hence, models that are undergoing relatively low frequency updates in PhysX can exist in an environment that demands much higher frequency updates for haptics. We use a collision handling layer to interface between the physical response provided by PhysX and the haptic rendering device to provide both real time tissue response and force feedback. Results Our simulator integrates a bimanual haptic interface for force-feedback and per-pixel shaders for graphics realism in real time. To demonstrate the effectiveness of our approach, we present the simulation of the Laparoscopic Adjustable Gastric Banding (LAGB) procedure as a case study. Conclusions To develop complex and realistic surgical trainers with realistic organ geometries and tissue properties demands stable physics-based deformation methods which are not always compatible with the interaction level required for such trainers. We have shown that combining different modeling

  16. Tevatron physics

    SciTech Connect

    John Womersley

    2003-01-03

    These lectures form a personal, and not necessarily comprehensive, survey of physics at the Fermilab Tevatron proton-antiproton collider. They cover detectors, analysis issues, and physics prospects for the current Tevatron run.

  17. Physical Allergy

    MedlinePlus

    ... physical stimulus. Physical stimuli include the following: Cold Sunlight Heat or other stimuli that cause sweating (such ... a foreign substance and attacks it. Sensitivity to sunlight (photosensitivity) is an example. Ultraviolet light changes proteins ...

  18. Physics Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Seventeen experiments in physics are described to demonstrate various physical phenomena. These include the areas of velocity of sound, damped oscillations, plastic deformation of wires, materials, testing, air resistance, spectrum optical filtering, and some new improvised apparatus. (PS)

  19. Physical Therapists

    MedlinePlus

    ... specific educational prerequisites, such as classes in anatomy, physiology, biology, chemistry, and physics. Some programs admit college ... therapist programs often include courses in biomechanics, anatomy, physiology, neuroscience, and pharmacology. Physical therapist students also complete ...

  20. Sports Physicals

    MedlinePlus

    ... season. What Is a Sports Physical? In the sports medicine field, the sports physical exam is known as ... to consider possible conditions you may have. Most sports medicine doctors believe the medical history is the most ...

  1. Physics Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Described are 13 physics experiments/demonstrations applicable to introductory physics courses. Activities include: improved current balance, division circuits, liquid pressure, convection, siphons, oscillators and modulation, electrical resistance, soap films, Helmholtz coils, radioactive decay, and springs. (SL)

  2. Sports Physicals

    MedlinePlus

    ... stronger athlete. previous continue When & Where Should I Go for a Sports Physical? Some people go to their own doctor for a sports physical; ... one at school. During school physicals, you may go to half a dozen or so "stations" set ...

  3. On the Role of Mathematics in Physics: A Constructivist Epistemic Perspective

    NASA Astrophysics Data System (ADS)

    Quale, Andreas

    2011-07-01

    The association between the observable physical world and the mathematical models used in theoretical physics to describe this world is examined. Such models will frequently exhibit solutions that are unexpected, in the sense that they describe physical situations which are different from that which the physicist may initially have had in mind when the model is employed. It will then often be the case that such an unexpected solution actually represents a physically realisable situation. However, this solution may also, in some cases, describe a system that is unphysical—i.e. a system that, according to our physical intuition, simply cannot exist. It is argued that this latter fact poses a problem for the epistemic position of realism in physics: a mathematical theory that professes to give a correct description of physical reality should not give rise to such unrealistic solutions. Some concrete examples are examined, and their implications are discussed from the relativist epistemic perspective that is implicit in the theory of radical constructivism. It is suggested that the occurrence of these unphysical solutions also has significance for the teaching of physics. In conclusion, it is advocated that the students be exposed, from the start of their physics education (mainly in secondary school), to the relativist ontology that is advocated by radical constructivism; here the appearance of unphysical solutions does not pose an epistemic problem.

  4. Neutrino physics

    SciTech Connect

    Harris, Deborah A.; /Fermilab

    2008-09-01

    The field of neutrino physics has expanded greatly in recent years with the discovery that neutrinos change flavor and therefore have mass. Although there are many neutrino physics results since the last DIS workshop, these proceedings concentrate on recent neutrino physics results that either add to or depend on the understanding of Deep Inelastic Scattering. They also describe the short and longer term future of neutrino DIS experiments.

  5. Action physics

    NASA Astrophysics Data System (ADS)

    McGinness, Lachlan P.; Savage, C. M.

    2016-09-01

    More than a decade ago, Edwin Taylor issued a "call to action" that presented the case for basing introductory university mechanics teaching around the principle of stationary action [E. F. Taylor, Am. J. Phys. 71, 423-425 (2003)]. We report on our response to that call in the form of an investigation of the teaching and learning of the stationary action formulation of physics in a first-year university course. Our action physics instruction proceeded from the many-paths approach to quantum physics to ray optics, classical mechanics, and relativity. Despite the challenges presented by action physics, students reported it to be accessible, interesting, motivational, and valuable.

  6. Physical composition

    NASA Astrophysics Data System (ADS)

    Healey, Richard

    2013-02-01

    Atomistic metaphysics motivated an explanatory strategy which science has pursued with great success since the scientific revolution. By decomposing matter into its atomic and subatomic parts physics gave us powerful explanations and accurate predictions as well as providing a unifying framework for the rest of science. The success of the decompositional strategy has encouraged a widespread conviction that the physical world forms a compositional hierarchy that physics and other sciences are progressively articulating. But this conviction does not stand up to a closer examination of how physics has treated composition, as a variety of case studies will show.

  7. The paradox of realism and "authenticity" in entertainment-education: a study of adolescents' views about anti-drug abuse dramas.

    PubMed

    Guttman, Nurit; Gesser-Edelsburg, Anat; Israelashvili, Moshe

    2008-01-01

    The successful use of drama as a vehicle to influence health-related attitudes and behaviors is credited to its ability to elicit an emotional experience and identification among audience members. This study investigated the views of adolescents regarding an entertainment-education (EE) component of their school's anti-drug program - a live performance of a professionally produced anti-drug abuse drama. The analysis draws mainly on data collected from 64 focus groups, conducted in 24 schools across Israel, and open-ended responses to questionnaires administered to more than 1,700 adolescents. The adolescents were generally entertained by the anti-drug abuse drama and moved by its "authenticity," which emerged as a central construct in this study. Yet only a fraction identified with the characters and many remained unwilling to "tell" on a friend who uses drugs. Drawing on these findings, implications to EE theory and practice are discussed, particularly as they relate to the drama's perceived realism or "authenticity," and its unintended effects.

  8. Climate Physics

    ERIC Educational Resources Information Center

    Space, William

    2007-01-01

    Numerous connections exist between climate science and topics normally covered in physics and physical science courses. For instance, lessons on heat and light can be used to introduce basic climate science, and the study of electric circuits provides a context for studying the relationship between electricity consumption and carbon pollution. To…

  9. Playful Physics

    NASA Technical Reports Server (NTRS)

    Weaver, David

    2008-01-01

    Effectively communicate qualitative and quantitative information orally and in writing. Explain the application of fundamental physical principles to various physical phenomena. Apply appropriate problem-solving techniques to practical and meaningful problems using graphical, mathematical, and written modeling tools. Work effectively in collaborative groups.

  10. Physics Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Describes equipment, activities, and experiments useful in physics instruction, including among others, a list of articles relating to physics topics, computer interface that makes a computer cost effective, use of a guitar in vibrating string experiments, and photoelectric aids to the measurement of distance, speed, velocity, and acceleration.…

  11. Getting Physical.

    ERIC Educational Resources Information Center

    Peterson, Erin

    1998-01-01

    Discusses how high schools are responding to the decline in student physical fitness with new facilities that attract students to fitness. Use of alternative sports, e.g., hiking, climbing, and in-line skating is discussed; as are creating new facilities that encourage student use through technology; and integrating physical education with other…

  12. Determination of the absolute configuration of (-)-(2R)-succinic-2-d acid by neutron diffraction study: Unambiguous proof of the absolute stereochemistry of the NAD/sup +//NADH interconversion

    SciTech Connect

    Yuan, H.S.H.; Stevens, R.C.; Fujita, S.; Watkins, M.I.; Koetzle, T.F.; Bau, R.

    1988-05-01

    The absolute configuration of the CHD group (D = deuterium) in (-)-(2R)-succinic-2-d acid, as prepared from (-)-(2S,3R)-malic-3-d acid, has been shown unambiguously to be R by the technique of single-crystal neutron diffraction. The optically active cation (+)-phenylethylammonium was used as the chiral reference. The structure of (C/sub 6/H/sub 5/CH/sub 3/CHNH/sub 3/)/sup +/(HOOCCH/sub 2/CHDCOOO)/sup -/ has been studied with x-ray diffraction at room temperature and neutron diffraction at room temperature and neutron diffraction at 100 K. Crystal data from the neutron diffraction analysis of the phenylethylammonium slat of the title compound at 100 K: space group P2/sub 1/; a = 8.407 /angstrom/, b = 8.300 /angstrom/, c = 8.614 /angstrom/, ..beta.. = 91.20/degrees/; unit cell volume = 600.9 /angstrom//sup 3/, Z = 2. The result confirms the stereochemistry of the malate/succinate transformation, as well as the NAD/sup +//NADH interconversion, and demonstrates the usefulness of the single-crystal neutron diffraction method for determining the absolute configuration of molecules having a chiral monodeuteriomethylene group.

  13. Physics Phridays

    NASA Astrophysics Data System (ADS)

    Falbo, Maria

    2007-12-01

    Teaching high school physics involves cheerleading, coaching, and acting (in addition to course preparation, equipment maintenance/construction, and grading). One is like a performer that has to be "on" all the time to keep the attention and interest of students in order to engage them in the content. But what happens once the course is over? We hope that we have sparked some interest in physics that will continue and that our students take what they've learned with them, but the reality is often disappointing. Can we do better than hope? "Physics Phridays" might be a starting point.

  14. Physics Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Presents activities, experiments, demonstrations, and equipment for physics instruction, including computer applications of sports biomechanics, vibrating magnetometer, alternative uses for an environmental comparator, CMOS integrated circuit logic tutor, and an activity demonstrating positive and negative leakage. (JN)

  15. Physics Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Twelve ideas are presented for physics teachers to implement in the laboratory or classroom. Topics covered include electromagnetic induction, microbalance, capacitors, determination of light velocity, and the compound pendulum. Information regarding laboratory equipment is also provided. (PS)

  16. Physics olympiad

    NASA Astrophysics Data System (ADS)

    Five high school physics students will represent the U.S. at the 20th International Physics Olympiad, July 14-25 in Warsaw, Poland. The Olympiad has been held annually since 1967; this is the fourth year the U.S. will compete. The American Association of Physics Teachers administers the U.S. program; AGU is a principal sponsoring organization of the Olympiad, as is the American Institute of Physics.The students are Derrick Bass, North Miami Beach High School, Miami Beach, Fla.; Steven Gubser, Cherry Creek High School, Englewood, Colo.; Jason Jacobs, Baldwin Senior High School, Baldwin, N.Y.; Jessica Millar, West High School, Madison, Wise; and James Sarvis, Thomas Jefferson High School, Alexandria, Va.

  17. Physics Notes

    ERIC Educational Resources Information Center

    School Science Review, 1973

    1973-01-01

    Ideas are proposed for physics teachers to use in their classrooms. Subjects include: alpha particles, spectrometer experiments, refractive index of glass, measurement of surface tension, projectile motion, and radiant heat. (PS)

  18. Contest Physics.

    ERIC Educational Resources Information Center

    Moehnke, Randy

    1994-01-01

    Discusses the use of contests to keep physics interesting and exciting for the students. Includes: balloon car, egg drop, tennis ball catapult, bridge building, mousetrap vehicle, musical instrument, slide photo, electric junk dissection, windmill generator, and solar heater. (MVL)

  19. Supercollider physics

    SciTech Connect

    Quigg, C.

    1985-03-01

    The physics that can be explored with multi-TeV supercolliders is reviewed, including parton distributions, hadron jet production, the standard electroweak theory and minimal extensions to it, technicolor, supersymmetry, and compositeness. 19 refs., 11 figs. (LEW)

  20. Environmental Physics

    ERIC Educational Resources Information Center

    Saperstein, Alvin M.

    1976-01-01

    Describes a one quarter introductory college physics course for nonscience majors which concentrates upon energy, energy systems, and relevant practical situations exemplifying energy laws. Results indicate the course is also suitable as a preparatory course for preprofessional students. (SL)

  1. Physical Abuse

    MedlinePlus

    ... seniors who are not abused. What are the indicators? Indicators are signs or clues that abuse has ... clusters of indicators that suggest a problem. Physical indicators Sprains, dislocations, fractures, or broken bones Burns from ...

  2. Magic Physics?

    ERIC Educational Resources Information Center

    Featonby, David

    2010-01-01

    This article examines several readily available "magic tricks" which base their "trickery" on physics principles, and questions the use of the word "magic" in the 21st century, both in popular children's science and in everyday language. (Contains 18 figures.)

  3. Physics Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Describes physics experiments and apparatus construction for studies in astronomy, electricity, wave measurement and speed, the behavior of steel, and intermolecular forces. Includes a detailed description of how to simulate apparent trajectories of the moon and sun. (CS)

  4. Charm physics

    NASA Astrophysics Data System (ADS)

    van Tilburg, J.

    2013-11-01

    Charm physics is an active and productive field at hadron colliders. In these proceedings an overview of recent results in charm physics from the Tevatron and LHC experiments is given. Highlighted are the measurements of open charm production and production asymmetries, the recent precision measurements of the D masses, the confirmation of mixing in the D0 system, the searches for CP violation in the charm system and the searches for rare charm decays.

  5. Ultrasound physics.

    PubMed

    Shriki, Jesse

    2014-01-01

    Bedside ultrasound has become an important modality for obtaining critical information in the acute care of patients. It is important to understand the physics of ultrasound in order to perform and interpret images at the bedside. The physics of both continuous wave and pulsed wave sound underlies diagnostic ultrasound. The instrumentation, including transducers and image processing, is important in the acquisition of appropriate sonographic images. Understanding how these concepts interplay with each other enables practitioners to obtain the best possible images.

  6. Constructing the principles: Method and metaphysics in the progress of theoretical physics

    NASA Astrophysics Data System (ADS)

    Glass, Lawrence C.

    This thesis presents a new framework for the philosophy of physics focused on methodological differences found in the practice of modern theoretical physics. The starting point for this investigation is the longstanding debate over scientific realism. Some philosophers have argued that it is the aim of science to produce an accurate description of the world including explanations for observable phenomena. These scientific realists hold that our best confirmed theories are approximately true and that the entities they propose actually populate the world, whether or not they have been observed. Others have argued that science achieves only frameworks for the prediction and manipulation of observable phenomena. These anti-realists argue that truth is a misleading concept when applied to empirical knowledge. Instead, focus should be on the empirical adequacy of scientific theories. This thesis argues that the fundamental distinction at issue, a division between true scientific theories and ones which are empirically adequate, is best explored in terms of methodological differences. In analogy with the realism debate, there are at least two methodological strategies. Rather than focusing on scientific theories as wholes, this thesis takes as units of analysis physical principles which are systematic empirical generalizations. The first possible strategy, the conservative, takes the assumption that the empirical adequacy of a theory in one domain serves as good evidence for such adequacy in other domains. This then motivates the application of the principle to new domains. The second strategy, the innovative, assumes that empirical adequacy in one domain does not justify the expectation of adequacy in other domains. New principles are offered as explanations in the new domain. The final part of the thesis is the application of this framework to two examples. On the first, Lorentz's use of the aether is reconstructed in terms of the conservative strategy with respect to

  7. Testing the realism of a topography-driven model (FLEX-Topo) in the nested catchments of the Upper Heihe, China

    NASA Astrophysics Data System (ADS)

    Gao, H.; Hrachowitz, M.; Fenicia, F.; Gharari, S.; Savenije, H. H. G.

    2014-05-01

    Although elevation data are globally available and used in many existing hydrological models, their information content is still underexploited. Topography is closely related to geology, soil, climate and land cover. As a result, it may reflect the dominant hydrological processes in a catchment. In this study, we evaluated this hypothesis through four progressively more complex conceptual rainfall-runoff models. The first model (FLEXL) is lumped, and it does not make use of elevation data. The second model (FLEXD) is semi-distributed with different parameter sets for different units. This model uses elevation data indirectly, taking spatially variable drivers into account. The third model (FLEXT0), also semi-distributed, makes explicit use of topography information. The structure of FLEXT0 consists of four parallel components representing the distinct hydrological function of different landscape elements. These elements were determined based on a topography-based landscape classification approach. The fourth model (FLEXT) has the same model structure and parameterization as FLEXT0 but uses realism constraints on parameters and fluxes. All models have been calibrated and validated at the catchment outlet. Additionally, the models were evaluated at two sub-catchments. It was found that FLEXT0 and FLEXT perform better than the other models in nested sub-catchment validation and they are therefore better spatially transferable. Among these two models, FLEXT performs better than FLEXT0 in transferability. This supports the following hypotheses: (1) topography can be used as an integrated indicator to distinguish between landscape elements with different hydrological functions; (2) FLEXT0 and FLEXT are much better equipped to represent the heterogeneity of hydrological functions than a lumped or semi-distributed model, and hence they have a more realistic model structure and parameterization; (3) the soft data used to constrain the model parameters and fluxes in FLEXT

  8. Shock Treatment: Using Immersive Digital Realism to Restage and Re-examine Milgram’s ‘Obedience to Authority’ Research

    PubMed Central

    Haslam, S. Alexander; Reicher, Stephen D.; Millard, Kathryn

    2015-01-01

    Attempts to revisit Milgram’s ‘Obedience to Authority’ (OtA) paradigm present serious ethical challenges. In recent years new paradigms have been developed to circumvent these challenges but none involve using Milgram’s own procedures and asking naïve participants to deliver the maximum level of shock. This was achieved in the present research by using Immersive Digital Realism (IDR) to revisit the OtA paradigm. IDR is a dramatic method that involves a director collaborating with professional actors to develop characters, the strategic withholding of contextual information, and immersion in a real-world environment. 14 actors took part in an IDR study in which they were assigned to conditions that restaged Milgrams’s New Baseline (‘Coronary’) condition and four other variants. Post-experimental interviews also assessed participants’ identification with Experimenter and Learner. Participants’ behaviour closely resembled that observed in Milgram’s original research. In particular, this was evidenced by (a) all being willing to administer shocks greater than 150 volts, (b) near-universal refusal to continue after being told by the Experimenter that “you have no other choice, you must continue” (Milgram’s fourth prod and the one most resembling an order), and (c) a strong correlation between the maximum level of shock that participants administered and the mean maximum shock delivered in the corresponding variant in Milgram’s own research. Consistent with an engaged follower account, relative identification with the Experimenter (vs. the Learner) was also a good predictor of the maximum shock that participants administered. PMID:25730318

  9. A dose of realism for healthy urban policy: lessons from area-based initiatives in the UK.

    PubMed

    Thomson, H

    2008-10-01

    Many urban policies aim to improve areas and address socioeconomic deprivation. The resulting investment is often delivered through area-based programmes which incorporate initiatives to improve the physical, social and economic environment. Hypotheses that these investments can contribute to wider public health strategies are based on epidemiological data and used to support the concept of healthy urban policy. However, there is little evidence on their ability to generate positive impacts on socioeconomic or health outcomes. The lack of validating evidence on actual impacts raises two important questions: (1) Is area-based investment an effective strategy to tackle socioeconomic deprivation? (2) What is the prospect for new and improved evaluations to provide stronger evidence? Both the programmes of area investment and their accompanying evaluations have been criticised for being overly ambitious in what can be achieved by the investment and what can be measured by an evaluation. Area-based approaches to tackling deprivation have their advantages but a mix of area and individual-level targeting is likely to be needed. While there is scope to improve the utility of evaluation data there are also inevitable constraints on assessing and attributing impacts from urban investment. The inherent limitations to an area-based approach and the ongoing constraints on impact evaluation will inevitably temper expectations of what healthy urban policy can achieve. However, lack of evidence is not grounds to abandon the concept of healthy urban policy; adoption of more realistic expectations together with improved evaluation data may help to increase its credibility.

  10. [Physical urticarias].

    PubMed

    Barbaud, A

    2003-05-01

    Ten percent of chronic urticarias are physical urticarias. Patients suffering from physical urticaria all have a suggestive history with specific eliciting stimuli (cold, heat, water, sun.) and wheals in the areas where the stimulus acts. The involved pathomechanisms are not well known. An unknown allergen (related to a cold or a heat injury, a polar molecule contained in the stratum corneum and soluble into water, a photoallergen) could induce a mast cell mediator release, followed by an infiltration by eosinophil then neutrophils polymorphonuclears. T-cells are not highly involved. Dermographism, the most frequent can be cured by anti-H1. In diagnosing cholinergic urticaria physical exercise has to be done by the patient (jogging, running, riding), anti-H1 are efficient. In other physical urticarias (delayed-pressure, cold, solar, heat, vibratory urticarias) as to be managed as follows: (1) to perform specific tests with respectively (weights; ice cube; UVA, UVB and visible light exposure; hot water contained in a tube; a vortex mixer); (2) to avoid eliciting stimuli; (3) to treat the associated diseases e.g. in secondary cold urticaria; (4) to try to induce a physical tolerance, a review is enclosed concerning cold, solar, heat and aquagenic urticarias; (5) to associate or not non sedative 2(nd) generation antihistamines. All the other alternative treatments are discussed but none of them has been evaluated.

  11. Physics Olympics

    NASA Astrophysics Data System (ADS)

    Bush, Susan M.

    Academics, not athletics, were the game in the 1988 International Physics Olympiad held in Bad Ischl, Austria, June 23 to July 1. AGU was one of about 20 principal sponsoring organizations that helped send 135 students from 27 countries to compete; the American Institute of Physics was another. The U.S. team brought home three of the 22 silver medals for 12th, 17th, 26th, 79th, and 90th places.The 20 members ot the U.S. Physics Olympiad Team attended a week-long training camp at the University of Maryland, College Park. University professors, high school teachers, and physicists from private industry coached the students through intensive problem solving, laboratory investigation, and testing. Students heard guest lecturers and constantly supplied one another with problem challenges for practice.

  12. PHYSICS TODAY--INTRODUCTORY PHYSICS EDUCATION.

    ERIC Educational Resources Information Center

    1967

    THIS SPECIAL ISSUE OF "PHYSICS TODAY" REVIEWS THE STATUS OF SECONDARY SCHOOL PHYSICS, AS WELL AS COLLEGE PHYSICS AND PHYSICAL SCIENCE. SECONDARY LEVEL PROJECTS INCLUDE PHYSICAL SCIENCE STUDY COMMITTEE PHYSICS, HARVARD PROJECT PHYSICS, THE ENGINEERING CONCEPTS CURRICULUM PROJECT, AND THE NUFFIELD PROJECT. THOSE AT THE COLLEGE LEVEL…

  13. Magnetotail physics

    SciTech Connect

    Lui, A.T.Y.

    1987-01-01

    Recent theoretical and experimental investigations of magnetotails (MTs) are examined in reviews and reports based on papers presented at the Chapman Conference on Magnetotail Physics, held at the Johns Hopkins University Applied Physics Laboratory in October 1985. Topics addressed include the MT configuration, fluid and kinetic aspects of MT dynamics, active diagnosis of the earth MT, and the MTs of celestial objects. Also provided are an overview of the conference findings and summaries of panel discussions on injection-layer and Alfven-layer models, reconnection and viscous-interaction models of solar-wind/magnetosphere energy transfer, and phenomenological models of MT substorms.

  14. The stereochemistry of chlorophyll-c₃ from the haptophyte Emiliania huxleyi: the (13²R)-enantiomers of chlorophylls-c are exclusively selected as the photosynthetically active pigments in chromophyte algae.

    PubMed

    Mizoguchi, Tadashi; Kimura, Yuki; Yoshitomi, Taichi; Tamiaki, Hitoshi

    2011-11-01

    Chlorophyll(Chl)-c pigments in algae, diatoms and some prokaryotes are characterized by the fully conjugated porphyrin π-system as well as the acrylate residue at the 17-position. The precise structural characterization of Chl-c(3) from the haptophyte Emiliania huxleyi was performed. The conformations of the π-conjugated peripheral substituents, the 3-/8-vinyl, 7-methoxycarbonyl and 17-acrylate moieties were evaluated, in a solution, using nuclear Overhauser enhancement correlations and molecular modeling calculations. The rotation of the 17-acrylate residue was considerably restricted, whereas the other three substituents readily rotated at ambient temperature. Moreover, the stereochemistry at the 13²-position was determined by combination of chiral high-performance liquid chromatography (HPLC) with circular dichroism (CD) spectroscopy. Compared with the CD spectra of the structurally related, synthetic (13²R)- and (13²S)-protochlorophyllide(PChlide)-a, naturally occurring Chl-c₃ had exclusively the (13²R)-configuration. To elucidate this natural selection of a single enantiomer, we analyzed the three major Chl-c pigments (Chl-c₁, c₂ and c₃) in four phylogenetically distinct classes of Chl-c containing algae, i.e., heterokontophyta, dinophyta, cryptophyta and haptophyta using chiral HPLC. All the photosynthetic organisms contained only the (13²R)-enantiomerically pure Chls-c, and lacked the corresponding enantiomeric (13²S)-forms. Additionally, Chl-c₂ was found in all the organisms as the common Chl-c. These results throw a light on the biosynthesis as well as photosynthetic function of Chl-c pigments: Chl-c₂ is derived from 8-vinyl-PChlide-a by dehydrogenation of the 17-propionate to acrylate residues as generally proposed, and the (13²R)-enantiomers of Chls-c function as photosynthetically active, light-harvesting pigments together with the principal Chl-a and carotenoids.

  15. Complex systems: physics beyond physics

    NASA Astrophysics Data System (ADS)

    Holovatch, Yurij; Kenna, Ralph; Thurner, Stefan

    2017-03-01

    Complex systems are characterised by specific time-dependent interactions among their many constituents. As a consequence they often manifest rich, non-trivial and unexpected behaviour. Examples arise both in the physical and non-physical worlds. The study of complex systems forms a new interdisciplinary research area that cuts across physics, biology, ecology, economics, sociology, and the humanities. In this paper we review the essence of complex systems from a physicists' point of view, and try to clarify what makes them conceptually different from systems that are traditionally studied in physics. Our goal is to demonstrate how the dynamics of such systems may be conceptualised in quantitative and predictive terms by extending notions from statistical physics and how they can often be captured in a framework of co-evolving multiplex network structures. We mention three areas of complex-systems science that are currently studied extensively, the science of cities, dynamics of societies, and the representation of texts as evolutionary objects. We discuss why these areas form complex systems in the above sense. We argue that there exists plenty of new ground for physicists to explore and that methodical and conceptual progress is needed most.

  16. Physics Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Demonstrations, procedures, games, teaching suggestions and information on a variety of physics topics are presented, including hydraulic rams, units and formulae, static electric motors, a computer graphics program, diffraction, adaptation of a basic meter, photoelasticity, photo-diodes, radioactive decay, and analog-digital conversions. (DC)

  17. DOING Physics.

    ERIC Educational Resources Information Center

    Zwicker, Earl, Ed.

    1983-01-01

    Several good features of a projectile motion experiment (students fire their own rockets) are described, including accuracy achieved, low cost and relative safety. Also described is a simple novelty toy (originally distributed by McDonalds foods) illustrating physics concepts. Blowing on this toy pipe propels a thread around in a loop. (JN)

  18. Flipped Physics

    ERIC Educational Resources Information Center

    Kettle, Maria

    2013-01-01

    This paper defines flipped learning and then examines its practical implementation in AS and A2 level physics classes, that is, classes for 16-18 year olds. The effect of this teaching style on student learning behaviour and its impact on test results are evaluated. The paper recounts the difficulties of implementing it and evaluates student…

  19. Physical Security

    SciTech Connect

    2008-01-01

    The future of physical security at government facilities and national laboratories is rapidly progressing beyond the cliché of gates, guns and guards, and is quickly being replaced by radars, sensors and cameras. Learn more about INL's security research at http://www.facebook.com/idahonationallaboratory.

  20. Reliability physics

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Ross, R. G., Jr.

    1984-01-01

    Speakers whose topics relate to the reliability physics of solar arrays are listed and their topics briefly reviewed. Nine reports are reviewed ranging in subjects from studies of photothermal degradation in encapsulants and polymerizable ultraviolet stabilizers to interface bonding stability to electrochemical degradation of photovoltaic modules.

  1. "Explosive" Physics.

    ERIC Educational Resources Information Center

    Kienzynski, Mark J.

    1998-01-01

    Describes a physics demonstration in which two-liter plastic bottles can be used to show how force relates to pressure and area. Identical drinking straws are launched out of similar plastic bottles with different-sized openings. This demonstration proves qualitatively that pressure is inversely proportional to the area exposed to an object when a…

  2. Computational Physics.

    ERIC Educational Resources Information Center

    Borcherds, P. H.

    1986-01-01

    Describes an optional course in "computational physics" offered at the University of Birmingham. Includes an introduction to numerical methods and presents exercises involving fast-Fourier transforms, non-linear least-squares, Monte Carlo methods, and the three-body problem. Recommends adding laboratory work into the course in the…

  3. Physics Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Laboratory procedures, equipment, teaching ideas, and resource materials related to physics are discussed. Topics include the construction of a liquid-metal pump, a hydraulic jack, and an apparatus which helps teach time/velocity graphs; current/voltage characteristics of a tungsten filament lamp; and an electric circuit game. (DC)

  4. Physics Portfolios

    ERIC Educational Resources Information Center

    Whitworth, Brooke A.; Bell, Randy L.

    2013-01-01

    Traditionally, teachers assess students' physics understanding through lab activities, responses to open-ended word problems, and tests. But there is another way to measure student understanding, one in which students apply their learning to the world around them. This article shows how to implement student portfolios, which allow students to…

  5. Zombie physics

    NASA Astrophysics Data System (ADS)

    Ornes, Stephen

    2016-05-01

    What makes for a fun student project that provides useful results, a journal publication and a high-profile conference talk? Stephen Ornes describes how Alex Alemi and Matt Bierbaum spiced up their learning by mixing statistical physics with their love of zombie tales.

  6. Physical Linguistics.

    ERIC Educational Resources Information Center

    Tice, Bradley S.

    Physical linguistics is defined as the use of treatments from the field of speech pathology to enhance first and second language production in healthy individuals, resulting in increased quality and strength of phonation and articulation. A series of exercises for treating dysarthria (weakness, paralysis, discoordination, primary and secondary…

  7. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2009-11-01

    1. Physics competitions: aims and realizations One aim of physics competitions is to increase the interest of young students, primarily at upper secondary level, to physics and natural sciences in general. A competition has motivational aspects known usually from sports events or games—comparing one's own ability with others, of course with the desire to be better and to win. If competitions reach nationwide and even international levels, additional stimulation is created. Competitions provide greatest attraction to possible winners, to the group of gifted people in a particular field. This implies that science contests are excellent tools for the promotion of talented students. Traditional teaching has been shown to have problems in supporting this group of students. Very often teachers are overstretched with the demands of teaching both low- and high-level students. Extracurricular activities are therefore a good chance to relieve the teacher, and to give talented students the opportunity for appropriate training and challenge. The competitions, however, have a broader impact and address more young people than one might guess from the statements above. Training courses and selection at school level give a larger group of students extra and, to some extent, complimentary education in physics. The degree of complexity of the tasks corresponds very often to the standards of the next level of education in the school system. Interestingly, many physics competitions have their origin in countries beyond the former Iron Curtain. They started as regional and national tournaments, were joined by neighbouring countries and have grown, in some cases, to events with participants from more than 80 countries. Although the features mentioned above are common to the different competitions, there are distinct differences between them [1]. The International Physics Olympiad (IPhO) is the oldest international physics competition for students at upper secondary level [2]. It dates

  8. Interactive physically-based sound simulation

    NASA Astrophysics Data System (ADS)

    Raghuvanshi, Nikunj

    The realization of interactive, immersive virtual worlds requires the ability to present a realistic audio experience that convincingly compliments their visual rendering. Physical simulation is a natural way to achieve such realism, enabling deeply immersive virtual worlds. However, physically-based sound simulation is very computationally expensive owing to the high-frequency, transient oscillations underlying audible sounds. The increasing computational power of desktop computers has served to reduce the gap between required and available computation, and it has become possible to bridge this gap further by using a combination of algorithmic improvements that exploit the physical, as well as perceptual properties of audible sounds. My thesis is a step in this direction. My dissertation concentrates on developing real-time techniques for both sub-problems of sound simulation: synthesis and propagation. Sound synthesis is concerned with generating the sounds produced by objects due to elastic surface vibrations upon interaction with the environment, such as collisions. I present novel techniques that exploit human auditory perception to simulate scenes with hundreds of sounding objects undergoing impact and rolling in real time. Sound propagation is the complementary problem of modeling the high-order scattering and diffraction of sound in an environment as it travels from source to listener. I discuss my work on a novel numerical acoustic simulator (ARD) that is hundred times faster and consumes ten times less memory than a high-accuracy finite-difference technique, allowing acoustic simulations on previously-intractable spaces, such as a cathedral, on a desktop computer. Lastly, I present my work on interactive sound propagation that leverages my ARD simulator to render the acoustics of arbitrary static scenes for multiple moving sources and listener in real time, while accounting for scene-dependent effects such as low-pass filtering and smooth attenuation

  9. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2011-07-01

    International tests on competences, such as TIMSS or PISA, and knowledge of young students have revealed low average scores in many countries, often unexpectedly. One effective measure to increase the average standard of a population is to bring the last third of the group to a higher level. Therefore, many nations put some effort into this activity. This brings the danger that not enough attention is paid to students at the other end, those who are talented. Indeed, it is a very difficult task for a teacher to support the less able and at the same time challenge the gifted students, to lead them to the limits of their abilities and provide for a smooth transition to university study. Physics competitions have been proven to fulfil these last demands to a large degree, and therefore are an important additional and, to some extent, complementary tool for the promotion of talented students. This third special section on physics competitions in European Journal of Physics contains three papers, each dealing with a different form of science contest. The first continues the series of presentations of tasks performed at the International Young Physicists' Tournament, which was held in Vienna in 2011. First place went to the team from Singapore, and they have put their investigation on vertical oscillations of coupled magnets into written form (not required by the tournament, where an oral presentation and a defence and discussion are the central aspects). Their paper shows how rich in physics this problem is, and what level of solutions high-school students can already achieve. Sadly, those responsible for the organization of last year's International Physics Olympiad did not provide us with a report on this competition. This is unfortunate, since the Olympiad in Zagreb was very successful and, in particular, the experimental tasks were creative and demanding. Very similar to the aims and the execution of the Physics Olympiad is the International Olympiad on Astronomy

  10. Positron Physics

    NASA Technical Reports Server (NTRS)

    Drachman, Richard J.

    2003-01-01

    I will give a review of the history of low-energy positron physics, experimental and theoretical, concentrating on the type of work pioneered by John Humberston and the positronics group at University College. This subject became a legitimate subfield of atomic physics under the enthusiastic direction of the late Sir Harrie Massey, and it attracted a diverse following throughout the world. At first purely theoretical, the subject has now expanded to include high brightness beams of low-energy positrons, positronium beams, and, lately, experiments involving anti-hydrogen atoms. The theory requires a certain type of persistence in its practitioners, as well as an eagerness to try new mathematical and numerical techniques. I will conclude with a short summary of some of the most interesting recent advances.

  11. Physical Impairment

    NASA Astrophysics Data System (ADS)

    Trewin, Shari

    Many health conditions can lead to physical impairments that impact computer and Web access. Musculoskeletal conditions such as arthritis and cumulative trauma disorders can make movement stiff and painful. Movement disorders such as tremor, Parkinsonism and dystonia affect the ability to control movement, or to prevent unwanted movements. Often, the same underlying health condition also has sensory or cognitive effects. People with dexterity impairments may use a standard keyboard and mouse, or any of a wide range of alternative input mechanisms. Examples are given of the diverse ways that specific dexterity impairments and input mechanisms affect the fundamental actions of Web browsing. As the Web becomes increasingly sophisticated, and physically demanding, new access features at the Web browser and page level will be necessary.

  12. Astroparticle physics

    NASA Astrophysics Data System (ADS)

    Ong, Rene A.

    2013-12-01

    Astroparticle physics is a rapidly developing field that has a high degree of overlap with particle physics and astronomy. This paper summarizes recent results and leading experiments in two selected areas: very high energy astrophysics and dark matter. Both areas have made great progress in the last 5 years due to improved instrumentation and a growing community. In very high energy astrophysics, many sources of GeV and TeV radiation have been detected and the challenge now is to fully understand the processes involved at these sites of extreme particle acceleration. In the area of dark matter, there is a close scientific connection between astroparticle experiments and the Large Hadron Collider (LHC). The combination of the LHC, direct-detection and indirect-detection experiments provide critical complementarity and unprecedented sensitivity in the quest to understand this deep mystery.

  13. Youtube Physics

    NASA Astrophysics Data System (ADS)

    Riendeau, Diane

    2012-02-01

    Through the use of YouTube, we can show our students demos that we do not have the capability of doing in class. We can use these videos to inspire them and show them some of the cutting-edge discoveries in our field. We can also show them videos from around the world. Students need to realize that the physics community is global, not just national. They should learn to marvel in the discoveries made by physicists from all nations.

  14. b Physics

    SciTech Connect

    Perret, Pascal

    1998-10-19

    A summary of the most recent and important measurements in b physics is presented. The production of beauty particles in Z decays, b quark couplings, lifetimes, B{sup 0}-B{sup 0} oscillations, semileptonic b decays and studies of the number of charm quarks produced in b decays are reviewed. Extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |V{sub td}|, |V{sub cb}|, |V{sub ub}| and implication for |V{sub ts}| are discussed.

  15. Solar Physics

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    The areas of emphasis are: (1) develop theoretical models of the transient release of magnetic energy in the solar atmosphere, e.g., in solar flares, eruptive prominences, coronal mass ejections, etc.; (2) investigate the role of the Sun's magnetic field in the structuring of solar corona by the development of three-dimensional numerical models that describe the field configuration at various heights in the solar atmosphere by extrapolating the field at the photospheric level; (3) develop numerical models to investigate the physical parameters obtained by the ULYSSES mission; (4) develop numerical and theoretical models to investigate solar activity effects on the solar wind characteristics for the establishment of the solar-interplanetary transmission line; and (5) develop new instruments to measure solar magnetic fields and other features in the photosphere, chromosphere transition region and corona. We focused our investigation on the fundamental physical processes in solar atmosphere which directly effect our Planet Earth. The overall goal is to establish the physical process for the Sun-Earth connections.

  16. Solar Physics - Plasma Physics Workshop

    NASA Technical Reports Server (NTRS)

    Baum, P. J.; Beckers, J. M.; Newman, C. E.; Priest, E. R.; Rosenberg, H.; Smith, D. F.; Sturrock, P. A.; Wentzel, D. G.

    1974-01-01

    A summary of the proceedings of a conference whose purpose was to explore plasma physics problems which arise in the study of solar physics is provided. Sessions were concerned with specific questions including the following: (1) whether the solar plasma is thermal or non-themal; (2) what spectroscopic data is required; (3) what types of magnetic field structures exist; (4) whether magnetohydrodynamic instabilities occur; (5) whether resistive or non-magnetohydrodynamic instabilities occur; (6) what mechanisms of particle acceleration have been proposed; and (7) what information is available concerning shock waves. Very few questions were answered categorically but, for each question, there was discussion concerning the observational evidence, theoretical analyses, and existing or potential laboratory and numerical experiments.

  17. Women in Physics.

    ERIC Educational Resources Information Center

    Roth, Laura M.; O'Fallon, Nancy M.

    This booklet presents information about career opportunities for women in physics. Included are summaries of research areas in physics (optical physics, solid-state physics, materials science, nuclear physics, high-energy physics, astrophysics, cryogenics, plasma physics, biophysics, atmospheric physics) and differences between theory and…

  18. [Laser physics].

    PubMed

    Banús Gassol, J M

    2008-11-01

    The commission of this article plunged me into doubt. First I should confess that I don't find excuse to escape this part if somebody wants to minimally deepen in the knowledge of the biological effects of this energy source. Secondly, when we talk about results, we use terms made and defined by Physics. Often we have polemics about results, and what really happens is that we don't reach agreements because we refer to different terms to explain the same observation; in conclusion we cannot understand each other because we do not know the adequate terms; for example, hypoxemia as oxygen deficit, which is true in an anemic patient as well as in a low oxygen saturation rate. In consequence, a good review of these concepts seems necessary to me. The third reason is the confusion that exists in our environment, I think sometimes of interest, about properties and effects of different types of laser. Only a minimal knowledge of physics will help us to state the scientific basis for understanding. The problems, nevertheless, accumulate due to the fact that the universe to which this article is directed is formed by urologists. What Physics education should we suppose they have? Superficial? Medium? Is it a collective with a uniform knowledge, being it whatever it is? The implication is clear. The article depth will depend on the answers to these questions. Nevertheless, the aim of the authors is to give a base enough to know what the laser is and how it acts. For that, the answer I gave to my questions is that the reader should understand the article and have enough base for, at least, reading critically the articles about laser published in urological journals.

  19. Hadron physics

    SciTech Connect

    Bunce, G.

    1984-05-30

    Is all hadronic physics ultimately describable by QCD. Certainly, many disparate phenomena can be understood within the QCD framework. Also certainly, there are important questions which are open, both theoretically (little guidance, as yet) and experimentally, regarding confinement. Are there dibaryons, baryonium, glueballs. In addition, there are experimental results which at present do not have an explanation. This talk, after a short section on QCD successes and difficulties, will emphasize two experimental topics which have recent results - glueball spectroscopy and exclusive reactions at large momentum transfer. Both are experimentally accessible in the AGS/LAMPF II/AGS II/TRIUMF II/SIN II energy domain.

  20. EDITORIAL: Physics competitions Physics competitions

    NASA Astrophysics Data System (ADS)

    Jordens, H.; Mathelitsch, L.

    2010-07-01

    This editorial opens the second special section on physics competitions in European Journal of Physics. In the first section last year, we asked for feedback on the idea of such a section and on the content of the articles. We received no answer whatsoever, which can be interpreted in two ways: the section is not interesting enough to raise motivation for feedback, or the reader is satisfied. Having no indication which scenario is the correct one, we are optimistic and favour the second. The section at hand contains three articles. Again, as last year, the organizer of the annual Olympiad reports on tasks and outcomes of this competition. The Olympiad took place in Merida, Mexico, and was by far the largest event with 316 contestants from 68 countries. Again, the predominance of Asian/Chinese students was manifest, showing how serious the training is taken by both their authorities and students. Unfortunately, the winners of the last International Young Physicists' Tournament (IYPT), the team from Korea, did not accept the offer to report on their prize-winning contribution. We are thankful that two students from Austria, who achieved second place with their team, took over and reported on the task which they presented in the finals of the competition. It connects the fields of sport and physics and explains a special move in skateboarding. The third contribution introduces a different competition, 'International Conference of Young Scientists'. On one hand, as in the Olympiad, it addresses individuals, not teams. On the other, as in the IYPT, students have several months to prepare and also the quality of the presentation is an important element of the judgment. In fact, this competition comes closer to real scientific research compared to the other events. Finally and again, we hope that this section will serve several purposes: To show the competitions as a very important tool in the support of gifted students. To raise awareness amongst university teachers, and

  1. Physical Activity (Exercise)

    MedlinePlus

    ... Physical activity (exercise) fact sheet ePublications Physical activity (exercise) fact sheet How can physical activity improve my ... recent hip surgery More information on physical activity (exercise) For more information about physical activity (exercise), call ...

  2. For Realism in Children's Fiction.

    ERIC Educational Resources Information Center

    Stibbs, Andrew

    1980-01-01

    Points out the sometimes excessive lengths that authors carry the suspension of reality in children's fiction. Advocates a more disciplined imagination, and rejection of untrue or impossible worlds. (HTH)

  3. Death: Realism in Children's Books.

    ERIC Educational Resources Information Center

    Danielson, Kathy Everts

    In the past, books for children treated death fearfully, morbidly, and didactically, but now children's literature treats death in a more realistic manner and is sensitive to its emotional aspects. Current theories suggest that children perceive death differently at various ages. G. P. Koocher (1973) used J. Piaget's cognitive stages as the basis…

  4. Dynamical Realism and Uncertainty Propagation

    NASA Astrophysics Data System (ADS)

    Park, Inkwan

    In recent years, Space Situational Awareness (SSA) has become increasingly important as the number of tracked Resident Space Objects (RSOs) continues their growth. One of the most significant technical discussions in SSA is how to propagate state uncertainty in a consistent way with the highly nonlinear dynamical environment. In order to keep pace with this situation, various methods have been proposed to propagate uncertainty accurately by capturing the nonlinearity of the dynamical system. We notice that all of the methods commonly focus on a way to describe the dynamical system as precisely as possible based on a mathematical perspective. This study proposes a new perspective based on understanding dynamics of the evolution of uncertainty itself. We expect that profound insights of the dynamical system could present the possibility to develop a new method for accurate uncertainty propagation. These approaches are naturally concluded in goals of the study. At first, we investigate the most dominant factors in the evolution of uncertainty to realize the dynamical system more rigorously. Second, we aim at developing the new method based on the first investigation enabling orbit uncertainty propagation efficiently while maintaining accuracy. We eliminate the short-period variations from the dynamical system, called a simplified dynamical system (SDS), to investigate the most dominant factors. In order to achieve this goal, the Lie transformation method is introduced since this transformation can define the solutions for each variation separately. From the first investigation, we conclude that the secular variations, including the long-period variations, are dominant for the propagation of uncertainty, i.e., short-period variations are negligible. Then, we develop the new method by combining the SDS and the higher-order nonlinear expansion method, called state transition tensors (STTs). The new method retains advantages of the SDS and the STTs and propagates uncertainty analytically and nonlinearly.

  5. Applying Realism Theory in Afghanistan

    DTIC Science & Technology

    2011-06-01

    the Afghanistan strategy in order to meet changing national strategic objectives. Most recently the Obama Administration, following a nine month...Administration and the Obama Administration adjusted and modified the Afghanistan strategy in order to meet changing national strategic objectives. Most...modified the Afghanistan strategy in order to meet changing national strategic objectives. Unfortunately for the United States, the Bush

  6. Tumour physics.

    PubMed

    Drechsel, Willy Dieter

    2008-06-01

    During the cell division dynamic processes take place, the origin of which are to find in the physical characteristics of cell components. The most important characteristics are the electrical charge and the energy of the moving base components in a viscous cytoplasm. The interactions between the components lead as well known, to the emergence of hydrogen bonds between two DNA strands. The computations show that the strength of these bindings depends on three factors: first it is dependent on the length of a monotonous sequence, second it is dependent on the viscosity of the cytoplasm, and third it is dependent on the replication speed. In the study in detail is stated, how it affects the effectiveness of the DNA repair mechanism, mutation susceptibility, and thus also affects the cancer susceptibility.

  7. DUNE Physics

    SciTech Connect

    Strait, James

    2015-08-01

    The Deep Underground Neutrino Experiment is a worldwide effort to build a next-generation long-baseline neutrino experiment with a neutrino beam and near detector at Fermilab and a far detector at the Sanford Underground Research Facility 1,300 km from Fermilab. It is a merger of previous efforts and other interested parties to build, operate and exploit a staged 40-kt liquid argon detector and a high precision near detector exposed to a high-power, broad-band neutrino beam. The goals of the experiment are precision oscillation measurements, including CP violation and neutrino mass hierarchy determination, search for nucleon decay, and neutrino astrophysics, as well as precision neutrino physics at the near site.

  8. Atomic physics

    SciTech Connect

    Livingston, A.E.; Kukla, K.; Cheng, S.

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  9. From Dualism to Unity in Quantum Physics

    NASA Astrophysics Data System (ADS)

    Landé, Alfred

    2016-02-01

    Preface; Introduction; 1. Causality, chance, continuity; 2. States, observables, probabilities; 3. The metric law of probabilities; 4. Quantum dynamics; 5. Quantum fact and fiction; Retrospect. From dualism to unity, from positivism to realism; Appendix 1. Survey of elementary postulates; Appendix 2. Two problems of uniqueness; References; Index.

  10. Quantifying the Relationship between Dynamical Cores and Physical Parameterizations by Geostatistical Methods

    NASA Astrophysics Data System (ADS)

    Yorgun, M. S.; Rood, R. B.

    2010-12-01

    The behavior of atmospheric models is sensitive to the algorithms that are used to represent the equations of motion. Typically, comprehensive models are conceived in terms of the resolved fluid dynamics (i.e. the dynamical core) and subgrid, unresolved physics represented by parameterizations. Deterministic weather predictions are often validated with feature-by-feature comparison. Probabilistic weather forecasts and climate projects are evaluated with statistical methods. We seek to develop model evaluation strategies that identify like “objects” - coherent systems with an associated set of measurable parameters. This makes it possible to evaluate processes in models without needing to reproduce the time and location of, for example, a particular observed cloud system. Process- and object-based evaluation preserves information in the observations by avoiding the need for extensive spatial and temporal averaging. As a concrete example, we focus on analyzing how the choice of dynamical core impacts the representation of precipitation in the Pacific Northwest of the United States, Western Canada, and Alaska; this brings attention to the interaction of the resolved and the parameterized components of the model. Two dynamical cores are considered within the Community Atmosphere Model. These are the Spectral (Eulerian), which relies on global basis functions and the Finite Volume (FV), which uses only local information. We introduce the concept of "meteorological realism" that is, do local representations of large-scale phenomena, for example, fronts and orographic precipitation, look like the observations? A follow on question is, does the representation of these phenomena improve with resolution? Our approach to quantify meteorological realism starts with methods of geospatial statistics. Specifically, we employ variography, which is a geostatistical method which is used to measure the spatial continuity of a regionalized variable, and principle component

  11. Physics-10

    NASA Astrophysics Data System (ADS)

    Marinciuc, Mihai; Rusu, Spiridon

    The textbook is designated for the 10-th class of real and humanitarian lyceums, according the curriculum of the Ministry of Education of the Republic of Moldova for lyceums. It encomprises mechanics in 5 chapters (Kynematics (Trajectory, Relativity of the Motion, Circular Motion and other); Dynamics and the Forces in Nature (The mass and Force, Universal attraction, Elastic Forces, Friction, The motion of the Bodies under the action of many forces, The relativity Principle of Galilei and other); Statics; Mechanical Impuls and its conservation; Mechanical work and Mechanical Energy and its conservation( Mechanical work and Power, Kynetic Energy, The mechanical work of the Elastic Force, The conservation laws) and Molecular Physics and Thermdynamics in 5 chapters (The structure of the Matter; Gases and their properties (Simplest transformations, The molecular-kynetic theory, Real gases) ; Solids and Liquids (The Hook's law, Superficial tension, Dilatation and other); Phase transitions (including sublimation); (Calorimetry; Thermal machines; The second law of thermodynamics and other). The textbook includes also 8 laboratory (experimental) works, a number of questions for control and a number of 300 problems, half of which have answers. Short biographies of about 15 physicists are included. The textbook is illustrated with diagrames, paintings and portrets in black and white.

  12. [Physical therapy].

    PubMed

    Chohnabayashi, Naohiko

    2008-01-01

    Recently, pulmonary rehabilitation program is widely considered one of the most effective and evidence-based treatment for not only chronic obstructive pulmonary disease (COPD) but many clinical situations including neuro-muscular disease, post-operative status and weaning period from the ventilator, etc. The essential components of a pulmonary rehabilitation program are team assessment, patient training, psycho-social intervention, exercise, and follow-up. In 2003, Japanese medical societies (J. Thoracic Society, J. Pul. Rehabilitation Society and J. Physiotherapist Society) made a new guideline for pulmonary rehabilitation, especially how to aproach the execise training. As for the duration after surgical operation, airway cleaning is the important technique to prevent post-operative complications including pneumonia. Postural dranage technique is well known for such condition, at the same time, several instruments (flutter vulve, positive expiratory mask, high frequecy oscillation, etc) were also used for the patient to expectrate airway mucus easier. Lung transplantation is a new method of treatment for the critically-ill patients with chronic respiratoy failure. Several techniques of physical therapy are must be needed before and after lung transplantation to prevent both pulmonary infection and osteoporosis.

  13. Physics Based University Courses

    ERIC Educational Resources Information Center

    Beeby, J. L.

    1974-01-01

    Two physics courses which serve as alternatives to general college courses in physics are outlined: physics with astrophysics and physics with electronics. Details are given of the structure of the courses and third year options are specified. (DT)

  14. On the Stereochemistry of 2-Hydroxyethylphosphonate Dioxygenase

    PubMed Central

    2011-01-01

    Stereochemical investigations have shown that the conversion of 2-hydroxyethylphosphonate to hydroxymethylphosphonate by the enzyme HEPD involves removal of the pro-S hydrogen at C2 and, surprisingly, the loss of stereochemical information at C1. As a result, the mechanisms previously proposed for HEPD must be re-evaluated. PMID:21381767

  15. How Stereochemistry Considerations can Improve Pesticide Safety

    EPA Science Inventory

    About 30% of pesticides are chiral molecules and therefore exist as two or more stereoisomers, which can differ significantly in their toxicity, biodegradation, and persistence. Such differences can impact their relative safety to humans and environmental species. Enantiomers, mi...

  16. Bioorganic Chemistry. A Natural Reunion of the Physical and Life Sciences

    PubMed Central

    Poulter, C. Dale

    2009-01-01

    Organic substances were conceived as those found in living organisms. Although the definition was soon broadened to include all carbon-containing compounds, naturally occurring molecules have always held a special fascination for organic chemists. From these beginnings, molecules from nature were indespensible tools as generations of organic chemists developed new techniques for determining structures, analyzed the mechanisms of reactions, explored the effects conformation and stereochemistry on reactions, and found challenging new targets to synthesize. Only recently have organic chemists harnessed the powerful techniques of organic chemistry to study the functions of organic molecules in their biological hosts, the enzymes that synthesize molecules and the complex processes that occur in a cell. In this Perspective, I present a personal account my entrée into bioorganic chemistry as a physical organic chemist and subsequent work to understand the chemical mechanisms of enzyme-catalyzed reactions, to develop techniques to identify and assign hydrogen bonds in tRNAs through NMR studies with isotopically labeled molecules, and to study how structure determines function in biosynthetic enzymes with proteins obtained by genetic engineering. PMID:19323569

  17. Bioorganic chemistry. A natural reunion of the physical and life sciences.

    PubMed

    Poulter, C Dale

    2009-04-03

    Organic substances were conceived as those found in living organisms. Although the definition was soon broadened to include all carbon-containing compounds, naturally occurring molecules have always held a special fascination for organic chemists. From these beginnings, molecules from nature were indespensible tools as generations of organic chemists developed new techniques for determining structures, analyzed the mechanisms of reactions, explored the effects conformation and stereochemistry on reactions, and found challenging new targets to synthesize. Only recently have organic chemists harnessed the powerful techniques of organic chemistry to study the functions of organic molecules in their biological hosts, the enzymes that synthesize molecules and the complex processes that occur in a cell. In this Perspective, I present a personal account of my entree into bioorganic chemistry as a physical organic chemist and subsequent work to understand the chemical mechanisms of enzyme-catalyzed reactions, to develop techniques to identify and assign hydrogen bonds in tRNAs through NMR studies with isotopically labeled molecules, and to study how structure determines function in biosynthetic enzymes with proteins obtained by genetic engineering.

  18. Modeling and Reality in Early Twentieth-Century Physics

    NASA Astrophysics Data System (ADS)

    Seth, Suman

    2011-04-01

    Towards the end of 1913, Arnold Sommerfeld, Professor of theoretical physics at Munich University, sent a letter of congratulations to a young Niels Bohr. The Dane's now-classic trilogy of papers, which coupled Rutherford's conception of the atom with a ``planetary'' configuration of electrons, had just appeared. Sommerfeld saw the calculation of the Rydberg constant as a singular triumph and immediately spotted an opportunity to try to explain the Zeeman effect. Yet he also sounded a note of caution, confessing that he remained ``somewhat skeptical'' of atomic models in general. In this, of course, he was hardly alone. Bohr's atom was a particularly egregious example of a peculiar model, one requiring what even its creator considered ``horrid assumptions.'' Nonetheless, success bred conviction. Expanding upon Bohr's original ideas, Sommerfeld soon produced the so-called ``Bohr-Sommerfeld quantization conditions,'' using them to calculate a myriad of results. Experimental evidence, Sommerfeld argued in 1915, showed that quantised electron-paths ``correspond exactly to reality'' and possess ``real existence.'' This kind of realism would not, of course, last long. In 1925, Werner Heisenberg (earlier a student of Sommerfeld's) made scepticism about the details of the Bohr model into a methodological dictum, one later enshrined in the ``Copenhagen interpretation'' of quantum mechanics. This paper uses Sommerfeld's work from the turn of the twentieth century to the mid-1920s as a window onto a landscape involving multiple contestations over the legitimacy of atomic modelling. The surprise that greeted Heisenberg's and others' phenomenological insistences, we will see, can only be understood with reference to what should be considered a ``realist interlude'' in the history of twentieth century atomic physics, one inspired by the astonishing successes of Rutherford's and Bohr's imaginings.

  19. Physics Laboratory in UEC

    NASA Astrophysics Data System (ADS)

    Takada, Tohru; Nakamura, Jin; Suzuki, Masaru

    All the first-year students in the University of Electro-Communications (UEC) take "Basic Physics I", "Basic Physics II" and "Physics Laboratory" as required subjects; Basic Physics I and Basic Physics II are calculus-based physics of mechanics, wave and oscillation, thermal physics and electromagnetics. Physics Laboratory is designed mainly aiming at learning the skill of basic experimental technique and technical writing. Although 95% students have taken physics in the senior high school, they poorly understand it by connecting with experience, and it is difficult to learn Physics Laboratory in the university. For this reason, we introduced two ICT (Information and Communication Technology) systems of Physics Laboratory to support students'learning and staff's teaching. By using quantitative data obtained from the ICT systems, we can easily check understanding of physics contents in students, and can improve physics education.

  20. Physical basis for materials synthesis using biomineralization

    SciTech Connect

    De Yoreo, J; Orme, C; Dove, P; Teng, H

    2000-05-16

    -structured materials, the fundamental physical controls on carbonate biomineral formation remain poorly understood. Carbonates are formed in diverse environments almost exclusively by living organisms. These naturally occurring marine and fresh water minerals most commonly occur as the polymorphs of calcite, aragonite and vaterite which are nucleated and grown in the exoskeletons and tissues of marine and freshwater organisms ranging from simple bacteria and algae to crustaceans, molluscs, or sponges. It is known that the soluble fraction associated with mineralizing parts of organisms plays a primary role in crystal formation. In the formation of molluscan shells, this fraction is distinguished by the common presence of aspartic acid rich amino acid mixtures. It is also known that carbonates exposed to different polyamino acids exhibit different crystal habits. Belcher et al. showed that exposing growing CaCO{sub 3} crystals alternately to solutions containing polyanionic proteins associated with the aragonitic and calcitic layers of mollusc shells led to sequential switching of the crystal structure of the newly grown material between that of aragonite and calcite. Further work has demonstrated that these protein mixtures alter the morphology of the calcite growth surface and that they contain two fractions effecting growth: a step-binding fraction that inhibits step advancement on calcite surfaces, and a surface binding fraction that appears to lead to the subsequent nucleation of aragonite. Wierzbicki et al. found that polyaspartate molecules (ASP{sub 20}) bind to calcite surfaces. Finally, modeling of ASP{sub 15} binding to calcite planes predicts large binding energies for well defined orientations. This and related evidence shows that systematic relationships between crystal morphology and surface interactions with the reactive groups of the organic molecules must exist. However, the interplay between surface chemistry and the physical processes of nucleation and crystal growth

  1. Vietnamese women love physics

    NASA Astrophysics Data System (ADS)

    Anh, Kim Tran; Vu, Thi Bich; Nguyen, Ngoc Toan; Do, Tran Cat; Vo, Thach Son

    2013-03-01

    More and more females are studying physics and applying their physics knowledge in Vietnam. Women are well represented in physics in Vietnam, occupy high positions in the field, and win many national and international science awards. Overwhelmingly, women in physics in Vietnam have happy families with children who love physics.

  2. The physical therapy prescription.

    PubMed

    Onks, Cayce A; Wawrzyniak, John

    2014-07-01

    Physical therapy was first noted in the time of Hippocrates. The physical therapy visit includes a complete history, physical examination, and development of a treatment plan. Health care providers usually initiate a referral based on physical examination, symptoms, or a specific diagnosis. Physical therapy has been shown to be particularly helpful for musculoskeletal ailments, and has a growing body of evidence for use.

  3. Physics News in 1983.

    ERIC Educational Resources Information Center

    Schewe, Phillip F., Ed.

    Information is provided on some of the interesting and newsworthy developments in physics and its related fields during 1983. Areas considered include: (1) acoustics; (2) astrophysics; (3) condensed matter physics; (4) crystallography; (5) physics education; (6) electron and atomic physics; (7) elementary particle physics; (8) fluid dynamics; (9)…

  4. Some Physics Not in the Physical Review.

    ERIC Educational Resources Information Center

    Varney, Robert N.

    1982-01-01

    Discusses how physics was done at the University of California at Berkeley in the 1930s, focusing on the faculty and their accomplishments, physics experiments, physics instruments/equipment (cyclotron and rhumbatron), and research problems and their solutions. Includes reminiscences about lectures on thermodynamics presented by Otto Stern during…

  5. Physical Development: Taking Time for Physical Play

    ERIC Educational Resources Information Center

    Strickland, Eric

    2004-01-01

    This article discusses children's physical development through physical play. Here, the author gives ways to incorporate opportunities for physical play. For infants, time for play may have to revolve around nap schedules. This may mean allowing for different wake-sleep cycles for different infants. Teachers can divide the infants into groups so…

  6. [Approaching Physically Inactive Elderly for Physical Activity].

    PubMed

    Allmer, H; Allmer, M; Euskirchen, J; Froböse, I; Wallmann, B; Walter, T; Walschek, R

    2015-09-01

    The majority of elderly persons are still not sufficiently physically active. Therefore the aim of this study was to investigate different approaches (physical activity courses, poster, online-survey) for activating elderly to participate in physical activity. The most effective approach was target group physical activity courses with which higher course participation rates in men as well as in people with lower levels of education were achieved. Referring to the transtheoretical model (TTM) it is necessary for future analyses of target group approaches to consider more intensely the initial motivational position of physically inactive elderly.

  7. Guide to Physical Activity

    MedlinePlus

    ... Families ( We Can! ) Health Professional Resources Guide to Physical Activity Physical activity is an important part of your ... to injury. Examples of moderate-intensity amounts of physical activity Common Chores Washing and waxing a car for ...

  8. Quantum Physics for Beginners.

    ERIC Educational Resources Information Center

    Strand, J.

    1981-01-01

    Suggests a new approach for teaching secondary school quantum physics. Reviews traditional approaches and presents some characteristics of the three-part "Quantum Physics for Beginners" project, including: quantum physics, quantum mechanics, and a short historical survey. (SK)

  9. Physical Activity Assessment

    Cancer.gov

    Current evidence convincingly indicates that physical activity reduces the risk of colon and breast cancer. Physical activity may also reduce risk of prostate cancer. Scientists are also evaluating potential relationships between physical activity and other cancers.

  10. Physics For All -- yes, it's real physics

    NASA Astrophysics Data System (ADS)

    Eisenkraft, Arthur

    2012-02-01

    Can ``all'' students learn ``real'' physics? We want to provide instruction to a wider segment of the population including those students who will not go into STEM (Science, Technology, Engineering, Math) careers. We also want to maintain the integrity of physics, challenge all students, and not compromise the rigor of our courses. Accomplishing this requires a research guided approach to instruction, curriculum and assessment. Physics First and Physics for All have become a success story for thousands of students in urban, suburban, and rural districts. At the same time, the International Physics Olympiad and other competitions have raised the expectation of what the most motivated students can achieve. Many physics educators are exploring ways to set higher goals for our most gifted students while also providing physics instruction to students previously excluded from our physics classes. Many of the same issues that K-12 educators are struggling with are equally important to the college community as colleges try to educate both future physicists and an educated citizenry. Great novels and symphonies are accessible to people of different backgrounds and levels of expertise. We should develop strategies that enable us to share an understanding of physics with all students because everyone deserves an opportunity to reflect on the wondrous workings of our universe.

  11. History of Physics.

    ERIC Educational Resources Information Center

    Moyer, Albert E.

    1985-01-01

    Discusses the history of American physics, indicating that much effort has been on the atomic bond and high-energy physics, to the detriment of other topics and areas. To offset this tendency, significant research is going on in the history of solid-state physics, with glimmerings in the history of physics education. (JN)

  12. The Physics Plus Project.

    ERIC Educational Resources Information Center

    McKim, F. R.

    1983-01-01

    The Physics Plus Project is producing a series of pamphlets designed to supplement existing curricula with physics application topics (such as physics of sports, motor cars, weather, medical physics, energy). Discusses rationale for the projects, pamphlet production, distribution to schools, and use of pamphlet material on examinations. (JM)

  13. Physics and theology

    NASA Astrophysics Data System (ADS)

    Polkinghorne, John

    2014-01-01

    The role of theology in relation to science is not to try to tell physics how to answer its own proper questions. We have every reason to believe that physics questions will eventually receive physics answers. However there are meaningful and necessary questions which arise from considering the results of physics but which exceed its selflimited power to address.

  14. Doll's House Physics

    ERIC Educational Resources Information Center

    Kibble, Bob

    2009-01-01

    School physics rarely stands still for long. Environmental physics is now an option in some post-16 courses in England. The physics of environments, and in particular the built environment, offers a recognizable context in which to see the applications of physics at work. This article considers how a model doll's house might be used to help…

  15. History of Medical Physics.

    ERIC Educational Resources Information Center

    Laughlin, John S.

    1983-01-01

    Traces the development of basic radiation physics that underlies much of today's medical physics and looks separately at the historical development of two major subfields of medical physics: radiation therapy and nuclear medicine. Indicates that radiation physics has made important contributions to solving biomedical problems in medical…

  16. Nuclear winter - Physics and physical mechanisms

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Toon, O. B.; Pollack, J. B.; Ackerman, T. P.; Sagan, C.

    1991-01-01

    The basic physics of the environmental perturbations caused by multiple nuclear detonations is explored, summarizing current knowledge of the possible physical, chemical, and biological impacts of nuclear war. Emphasis is given to the impact of the bomb-generated smoke (soot) particles. General classes of models that have been used to simulate nuclear winter are examined, using specific models as examples.

  17. Training College Physics and Physical Science Teachers

    ERIC Educational Resources Information Center

    Henderson, R. B.; And Others

    1974-01-01

    Summarizes survey data about the need and appropriate character of graduate degree programs designed to prepare two-year and four-year college physics and physical science teachers. Indicates that future employment favors two-year college teachers with a master's degree in the region west of the Mississippi River. (CC)

  18. General Physics, Physics 12 [Science Curriculum Materials].

    ERIC Educational Resources Information Center

    Rochester City School District, NY.

    The Physics 12 curriculum guide represents one in a series of science guides especially designed to provide for the pupil whose primary interests are in non-science fields. The program provides study in physics in which fundamental concepts and understandings are developed, mathematical concepts are limited, and students are encouraged to relate…

  19. Physics through the 1990s: Nuclear physics

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The volume begins with a non-mathematical introduction to nuclear physics. A description of the major advances in the field follows, with chapters on nuclear structure and dynamics, fundamental forces in the nucleus, and nuclei under extreme conditions of temperature, density, and spin. Impacts of nuclear physics on astrophysics and the scientific and societal benefits of nuclear physics are then discussed. Another section deals with scientific frontiers, describing research into the realm of the quark-gluon plasma; the changing description of nuclear matter, specifically the use of the quark model; and the implications of the standard model and grand unified theories of elementary-particle physics; and finishes with recommendations and priorities for nuclear physics research facilities, instrumentation, accelerators, theory, education, and data bases. Appended are a list of national accelerator facilities, a list of reviewers, a bibliography, and a glossary.

  20. Physics and Skiing.

    ERIC Educational Resources Information Center

    Swinson, Derek B.

    1992-01-01

    Presents examples of physics as applied to the sport of skiing. Examples examine the physics of sliding, unweighting, ski turning, wind resistance, the parabolic and circular motion of aerial skiers, and the aerial maneuvers of ski jumpers. (MDH)